I'm contemplating replacing the flooded house batteries in my (new to me) Destiny, as the ones that came with it are toast due to the sellers not realizing they were no longer being charged by the alternator while driving. I've been kicking around if I should replace with new flooded or, bite the bullet and upgrade to AGMs? So, I've been doing a lot of research on AGMs and after reading Trojan's literature, I have what I believe may be a really dumb question.
Trojan publishes the following recommendation for temperature compensation for their AGMs. For every degree below 77 degrees F, increase your charging voltage by .0028 volts. For every degree above 77 degrees F, decrease the charging voltage by the same .0028 volts. In a hypothetical case, let's assume a battery is subjected to a temperature variation from 17 degrees F to 107 degrees F. That's 60 degrees below and 30 degrees above 77 degrees F. At 77 degrees Trojan recommends a 13.5 volt charge as a float voltage. If the temperature dropped to 17 degrees, the voltage increase would equal .165 volts. This brings the charge voltage to 13.665 volts. Using the same .0028 volts per degree of change, the decrease in voltage at 107 degrees would be .084 volts, which would equal 13.416 volts. Accordingly, the charge voltage would fluctuate a total of only .249 volts, for that temperature swing. That's just under 1/4 of one volt.
I find it highly unlikely that any of us can accurately determine if we are actually charging within those parameters, taking into consideration the inaccuracy from one volt meter to the next and the inaccuracy from one thermometer to the next unless, we are talking, laboratory grade instruments here. Add to this, the voltage drop that may occur from the charging circuit or the variation that might occur in the feedback to the charger from the battery temperature sensing probe, due to a lack of conductivity between the battery case or terminal and the probe.
I would like to ask anyone who knows the ins and outs on this subject, please comment and tell me why this whole temperature compensation thing isn't in reality, connected in some way with the guys selling the batteries or the chargers making an unwarranted, extra buck at the consumer's expense. (END OF DUMB QUESTION & RANT)
HELP!!! AGM Batteries (DUMB QUESTION & RANT)
-
HereComesTrouble
- Posts: 28
- Joined: June 19th, 2016, 9:16 pm
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
Hi Trouble,
I don't think your question sounds dumb at all. And to my mind, the thing about batteries, is that it's like they're like 85% science and 15%.... art? What I mean is, it's not just totally simple and clear like saying if I have five oranges and take away two I'll have three left.
Anyway, can we trust the battery manufacturers? Well, I don't know, but I guess at some point you (or I anyway) have to assume the engineers know what they are talking about and do want the best for the batteries. With the cost of, say, Lifeline AGM's I don't think they 're going to make more money by giving people wrong information just so they'll ruin batteries sooner and come back for more -- because considering the cost, who would if they didn't get good life out of them? Plus, they don't make money from us buying better charging equipment since they only make batteries, not chargers and etc.
One thing that really surprised me as I learned more about batteries and charging is how tenths of a volt make a difference. What?! And what do you mean 12 volts isn't a fully charged 12-volt battery? I mean, it just sounds weird at first. Heck, it still sounds weird but I now just accept it as true and act accordingly. I'm still no chemist or expert.
Fifteen years ago, when it wasn't just so easy to find information on the Internet, and when I was totally new at it, a friend and I bought what was then (to us) a HUGELY expensive battery bank of AGM batteries. And we pretty much trashed them within a year. We didn't have a proper charger, didn't know how to monitor them, and .... basically made every mistake you can make. We used them until the Sony car stereo beeped that the voltage was too low (I'm cringing just thinking about that). Poor, poor batteries! Now I know that in our situation then, AGM's were not a good choice. We'd have been better off with a set of flooded 6-volts (except we really weren't able to properly vent them -- it's hard on a boat -- so that was a good reason for AGM's). We just didn't have the knowledge or infrastructure to take care of them.
So anyway, I simply accept that they want what they want in the charging department, and I give it to them. I treat them royally, right down to the tenth of a volt, and so far (nowadays), they treat me well in return.
Now, as to your question on how do we know we are charging them that accurately? Well for starters, a good, adjustable, temperature-compensated charger WILL give them those very precise voltages. For example, my solar controller has a 30-day log of its charging data. I was just looking back at the log from last January, and I can see which were the coldest days - because the solar controller (which is a charger) was putting in over 15 volts in the absorption stage early in the day. Why 15 volts? Because the batteries want 14.4 volts at 77ºF, plus a certain fraction of added volts for every degree below that. It was probably around 30ºF that day, and so 15.x volts WAS the equivalent of the 14.4.
Measuring the voltage of the batteries ourselves (by "hand") is a bit trickier, because unless they are in the resting state (no power going in or out for 4-12 hours), the voltage you see is not that accurate. Because if the batteries are giving out power, or taking in power (charging), the voltage somewhat reflects that. But you CAN super accurately see what voltage your charger (shore or solar or alternator) is putting in. And if you have a good charger, programmed correctly, it will charge the batteries really precisely even when you aren't watching
You are also on the ball to realize how voltage drop can ruin these charging parameters. I mean so you get a super slick charger, set it up just so, and then..... lose a bunch of your precious voltage to voltage drop? Horrors! There are a couple of ways to help get around this.
1) Some chargers have the capability to run what is called a voltage sense wire. This is a small wire that constantly measures the batteries' voltage and reports it back to the charger. You still don't want a bunch of voltage drop in the "real" cables, but it can help by at least reporting a really accurate voltage to the charger.
2) Wire for as little voltage drop as you can. I *detest* giving anything away to voltage drop. There are a few ways to help avoid it:
a) Put the charging source and the batteries as close together as possible. The lower the voltage (and 12-volt system charging is pretty low) the worse voltage drop is. So what you DON'T want, for example, is a charger that is 28' of one-way wire distance from the batteries (looking at you here, Chinook!). You'd need fire hose to fix that. But put the charger four feet from the batteries and you can cut the voltage drop immensely and not have to use super gigantic wire.
b) Run higher voltage when possible, if appropriate. And example of this is my solar panels that I use as "ground panels." Since I want to have a decent amount of wire so that I can get them to the sun when I'm camped in the shade (but not have it be the diameter of garden hose), I run the two panels in series. This means that instead of 17.5 volts, they are running at 35 volts. Now I can have 30' of 8 gauge wire and still very little voltage drop (also, any drop here is before the charger, so it's lost power but doesn't affect the correct voltage number going the battery).
c) Once you have done a) and b) as much as possible, then the only thing left is to up the wire size until you have eliminated as much voltage drop as you want to. For charging sources I like to keep it close to 1%.
The alternator is never going to be a great charging source (unless you put a fancy DC to DC charger on it). It's not programmed to give three-stage charging or really any specific voltage, the wire run is long (and the amps can be large), and there is no temperature compensation. That's why I have mine on a manual combine switch and only use it once in a blue moon. Since I can stay charged up 95% of the time with my solar panels (and their charger/controller is giving the batteries precisely set voltage), why should I let "stupid charging" into the picture unless I have to? Of course sometimes it's nice, because it's a source of big amps that you can supply at will. One thing I found from boating is that you need options for different scenarios, and what's best at one time, may not be best at another time. So the alternator option is good to have, but not "great" in terms of smart charging.
Does that help? Hopefully not too rambly or tangential. And I don't know enough on a technical/engineering level to really answer your questions in any sort of scientific/chemical way.
BG
PS: And now just watch as lithium become more mainstream. Talk about a mind bender (because what they want in terms of charging is different yet again!).
I don't think your question sounds dumb at all. And to my mind, the thing about batteries, is that it's like they're like 85% science and 15%.... art? What I mean is, it's not just totally simple and clear like saying if I have five oranges and take away two I'll have three left.
Anyway, can we trust the battery manufacturers? Well, I don't know, but I guess at some point you (or I anyway) have to assume the engineers know what they are talking about and do want the best for the batteries. With the cost of, say, Lifeline AGM's I don't think they 're going to make more money by giving people wrong information just so they'll ruin batteries sooner and come back for more -- because considering the cost, who would if they didn't get good life out of them? Plus, they don't make money from us buying better charging equipment since they only make batteries, not chargers and etc.
One thing that really surprised me as I learned more about batteries and charging is how tenths of a volt make a difference. What?! And what do you mean 12 volts isn't a fully charged 12-volt battery? I mean, it just sounds weird at first. Heck, it still sounds weird but I now just accept it as true and act accordingly. I'm still no chemist or expert.
Fifteen years ago, when it wasn't just so easy to find information on the Internet, and when I was totally new at it, a friend and I bought what was then (to us) a HUGELY expensive battery bank of AGM batteries. And we pretty much trashed them within a year. We didn't have a proper charger, didn't know how to monitor them, and .... basically made every mistake you can make. We used them until the Sony car stereo beeped that the voltage was too low (I'm cringing just thinking about that). Poor, poor batteries! Now I know that in our situation then, AGM's were not a good choice. We'd have been better off with a set of flooded 6-volts (except we really weren't able to properly vent them -- it's hard on a boat -- so that was a good reason for AGM's). We just didn't have the knowledge or infrastructure to take care of them.
So anyway, I simply accept that they want what they want in the charging department, and I give it to them. I treat them royally, right down to the tenth of a volt, and so far (nowadays), they treat me well in return.
Now, as to your question on how do we know we are charging them that accurately? Well for starters, a good, adjustable, temperature-compensated charger WILL give them those very precise voltages. For example, my solar controller has a 30-day log of its charging data. I was just looking back at the log from last January, and I can see which were the coldest days - because the solar controller (which is a charger) was putting in over 15 volts in the absorption stage early in the day. Why 15 volts? Because the batteries want 14.4 volts at 77ºF, plus a certain fraction of added volts for every degree below that. It was probably around 30ºF that day, and so 15.x volts WAS the equivalent of the 14.4.
Measuring the voltage of the batteries ourselves (by "hand") is a bit trickier, because unless they are in the resting state (no power going in or out for 4-12 hours), the voltage you see is not that accurate. Because if the batteries are giving out power, or taking in power (charging), the voltage somewhat reflects that. But you CAN super accurately see what voltage your charger (shore or solar or alternator) is putting in. And if you have a good charger, programmed correctly, it will charge the batteries really precisely even when you aren't watching
You are also on the ball to realize how voltage drop can ruin these charging parameters. I mean so you get a super slick charger, set it up just so, and then..... lose a bunch of your precious voltage to voltage drop? Horrors! There are a couple of ways to help get around this.
1) Some chargers have the capability to run what is called a voltage sense wire. This is a small wire that constantly measures the batteries' voltage and reports it back to the charger. You still don't want a bunch of voltage drop in the "real" cables, but it can help by at least reporting a really accurate voltage to the charger.
2) Wire for as little voltage drop as you can. I *detest* giving anything away to voltage drop. There are a few ways to help avoid it:
a) Put the charging source and the batteries as close together as possible. The lower the voltage (and 12-volt system charging is pretty low) the worse voltage drop is. So what you DON'T want, for example, is a charger that is 28' of one-way wire distance from the batteries (looking at you here, Chinook!). You'd need fire hose to fix that. But put the charger four feet from the batteries and you can cut the voltage drop immensely and not have to use super gigantic wire.
b) Run higher voltage when possible, if appropriate. And example of this is my solar panels that I use as "ground panels." Since I want to have a decent amount of wire so that I can get them to the sun when I'm camped in the shade (but not have it be the diameter of garden hose), I run the two panels in series. This means that instead of 17.5 volts, they are running at 35 volts. Now I can have 30' of 8 gauge wire and still very little voltage drop (also, any drop here is before the charger, so it's lost power but doesn't affect the correct voltage number going the battery).
c) Once you have done a) and b) as much as possible, then the only thing left is to up the wire size until you have eliminated as much voltage drop as you want to. For charging sources I like to keep it close to 1%.
The alternator is never going to be a great charging source (unless you put a fancy DC to DC charger on it). It's not programmed to give three-stage charging or really any specific voltage, the wire run is long (and the amps can be large), and there is no temperature compensation. That's why I have mine on a manual combine switch and only use it once in a blue moon. Since I can stay charged up 95% of the time with my solar panels (and their charger/controller is giving the batteries precisely set voltage), why should I let "stupid charging" into the picture unless I have to? Of course sometimes it's nice, because it's a source of big amps that you can supply at will. One thing I found from boating is that you need options for different scenarios, and what's best at one time, may not be best at another time. So the alternator option is good to have, but not "great" in terms of smart charging.
Does that help? Hopefully not too rambly or tangential. And I don't know enough on a technical/engineering level to really answer your questions in any sort of scientific/chemical way.
BG
PS: And now just watch as lithium become more mainstream. Talk about a mind bender (because what they want in terms of charging is different yet again!).
1999 Concourse
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
I apply a strategy,or philosophy of charging,suggested by Ralph the electrical Maven of Bogart engineering.....It has performed well for me.....It goes like this...You have 3 sources of charging the batteries,alternator,charger that runs off shore or generator,Solar......notion: Batteries are typically damaged by undercharging,overcharging,(poor attention to water levels in the case of flooded cells and lack of equalization) notion:as batteries get full they offer resistance(not ohms) it gets harder to get that last 5% or more of charge into the battery.,Why is that important?concord who makes lifeline states batteries that are not fully charged will eventually walk down to the level they are being charged at.Conclusion:(here comes the philosophy) That important 5-10percent of battery charge,which is the amount I typically use boondocking overnight,is the most challenging to replace and where batteries get picky.
I rarely if ever plugin or run the generator,but I have read that battery maintainers run long enough can trickle in that last amount.So,though I replaced my charger/converter to a unprogramable multi stage smart charger I rarely ever use it to charge,
I also read and bought the philosophy about the alternator,but now for me,I am not so sure,I noticed my alternators output reduced itself to 13.2 volts once my batteries got full,which is a float charge.I assume the of the voltage regulator at the alternator.
I rely totally on my 150 watt solar panel,and the bogart trimetric connected to their charge controller to fully charge my batteries to 100 percent.It is programmable to tenths of a volt and temperature compensated.so it feeds my batteries when they get picky at the end,just the diet of volts they desire.
I run 6 gauge wire from the fixed roof panels to the controller adjacent to the battery compartment,the battery compartment itself is vented because Agm batteries are vented and can still gas a small amount.from the controller to a breaker and from there to the battery I run a larger gauge wire.just because I want to and figure it doesn't hurt.
THis setup is not for all people regardless of how they travel,But for me so far it has worked splendidly
I do think that for most travelers,the first and best upgrade is Adequate solar,and a really really good programmable temperature compensated charge controller. Rooney
I rarely if ever plugin or run the generator,but I have read that battery maintainers run long enough can trickle in that last amount.So,though I replaced my charger/converter to a unprogramable multi stage smart charger I rarely ever use it to charge,
I also read and bought the philosophy about the alternator,but now for me,I am not so sure,I noticed my alternators output reduced itself to 13.2 volts once my batteries got full,which is a float charge.I assume the of the voltage regulator at the alternator.
I rely totally on my 150 watt solar panel,and the bogart trimetric connected to their charge controller to fully charge my batteries to 100 percent.It is programmable to tenths of a volt and temperature compensated.so it feeds my batteries when they get picky at the end,just the diet of volts they desire.
I run 6 gauge wire from the fixed roof panels to the controller adjacent to the battery compartment,the battery compartment itself is vented because Agm batteries are vented and can still gas a small amount.from the controller to a breaker and from there to the battery I run a larger gauge wire.just because I want to and figure it doesn't hurt.
THis setup is not for all people regardless of how they travel,But for me so far it has worked splendidly
I do think that for most travelers,the first and best upgrade is Adequate solar,and a really really good programmable temperature compensated charge controller. Rooney
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
Sounds like we basically do the same thing: Have a highly programmable and temperature compensated solar controller (i.e. solar charger), it charges the batteries to 100% about 99% of the time, and the other 1% we use other means.
In my case I do have a similarly good 110 volt charger (programmable, temperature compensated) but... I haven't once used it. If I were to do it over again, given my usage pattern, I wouldn't even buy it. But then I don't tend to plug in or use the generator. If I did, it would charge my batteries just as "correctly" as the solar controller does.
Instead, for the two days in the past year that I have needed a little more charging, I have turned on the switch that combines my alternator/start battery with the house bank, and let that charge things up (less precisely, but workably). With the Scan Gauge, I can see that the voltage coming from the alternator varies between about 13.6 and 14.1 volts on my rig. It works for the bulk charge, which is fine for helping the solar panels from time to time.
And really, once I put my roof solar panels on, I don't see myself needing even that but once in a blue moon. Reason is that it's never that my solar panels can't keep up with my use; but rather it is because since I only have ground panels right now, they are not set out when I'm driving, and/or when I'm in say, a Wal-Mart parking lot, or if I'm stopping for just one night (lazy). Once I have roof panels I don't see needing the alternator charge (but I'll keep the switch in place, in case I want to use it that way and/or for self jump starting).
It might vary for others (less sunny climate, like to use generator/110 loads and charging).
One note on the alternator charge voltage: If you still have the stock wire connecting the two (I think it was 6AWG), there will be a fair amount of voltage drop, so what you see on something like a Scan Gauge will not actually be getting to the batteries. Also, the stock type of separator (e.g. Sure Power 1314 or 1315 is of a type that induces some voltage drop by virtue of its construction (vs. something like a Blue Sea 7622 that does not induce a voltage drop). Just something to keep in mind vis-a-vis alternator charging voltage.
I replaced my separator with a switch, since 99% of the time I *don't* want the alternator charging the AGM house bank. This way I only switch it "on" once in a blue moon (charging help, and/or self jump starting). This amounted to three days over the past year, for example. I have two small LED lights wired to the switch that come on when it is in combined position ("on"). One is a green light by the dash, and the other is a flashing red light in the coach. This way I don't forget and leave it combined (but as mentioned, I leave it "off" 99% of the time).
If I wanted them to automatically combine all the time by default, then I'd put in a Blue Sea 7622.
In my case I do have a similarly good 110 volt charger (programmable, temperature compensated) but... I haven't once used it. If I were to do it over again, given my usage pattern, I wouldn't even buy it. But then I don't tend to plug in or use the generator. If I did, it would charge my batteries just as "correctly" as the solar controller does.
Instead, for the two days in the past year that I have needed a little more charging, I have turned on the switch that combines my alternator/start battery with the house bank, and let that charge things up (less precisely, but workably). With the Scan Gauge, I can see that the voltage coming from the alternator varies between about 13.6 and 14.1 volts on my rig. It works for the bulk charge, which is fine for helping the solar panels from time to time.
And really, once I put my roof solar panels on, I don't see myself needing even that but once in a blue moon. Reason is that it's never that my solar panels can't keep up with my use; but rather it is because since I only have ground panels right now, they are not set out when I'm driving, and/or when I'm in say, a Wal-Mart parking lot, or if I'm stopping for just one night (lazy). Once I have roof panels I don't see needing the alternator charge (but I'll keep the switch in place, in case I want to use it that way and/or for self jump starting).
It might vary for others (less sunny climate, like to use generator/110 loads and charging).
One note on the alternator charge voltage: If you still have the stock wire connecting the two (I think it was 6AWG), there will be a fair amount of voltage drop, so what you see on something like a Scan Gauge will not actually be getting to the batteries. Also, the stock type of separator (e.g. Sure Power 1314 or 1315 is of a type that induces some voltage drop by virtue of its construction (vs. something like a Blue Sea 7622 that does not induce a voltage drop). Just something to keep in mind vis-a-vis alternator charging voltage.
I replaced my separator with a switch, since 99% of the time I *don't* want the alternator charging the AGM house bank. This way I only switch it "on" once in a blue moon (charging help, and/or self jump starting). This amounted to three days over the past year, for example. I have two small LED lights wired to the switch that come on when it is in combined position ("on"). One is a green light by the dash, and the other is a flashing red light in the coach. This way I don't forget and leave it combined (but as mentioned, I leave it "off" 99% of the time).
If I wanted them to automatically combine all the time by default, then I'd put in a Blue Sea 7622.
1999 Concourse
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
at the beginning,
I bought my Chinook,then,somewhat like Vivien Leigh(in A Street Car named Desire) relied on the expertise of Strangers,First) The original electrical engineers at TrailWagons Second)The other members of a Users Group (like this one) So I can appreciate inquiring minds,questioning.
Not every post,here (or there) is worth following ( even my own ).When I say a particular setup,works for me splendidly,I should qualify that by saying "it has so far" 2 years of positive use does not constitute success.
I suppose I also subscribe to the idea of "part science part art"when it comes to charging batteries.I read a good deal on the internet about batteries,when after buying my rig and taking my first trip,I heard the low battery alarm.I shook my fist at the sky and swore (This time like Vivien Leigh in Gone With the Wind)"I will never be without battery power again"
All of the experts I read whose posts educated me on the mysteries,and confusion surrounding battery charging,universally deferred to the quality and veracity of the info posted on The Trojan battery,and Lifeline battery websites......
Instead of setting up my own lab like Edison or Tesla,and letting the sparks fly in my lab coat and wild hair,I decided to accept the value of what was posted there.
I started my own inquiry by reading a reference to Handybobs Solar blog buried deep in the archives of the other chinook group...I googled it,read it and went from there.
I want to tread softly,in any of my dissent here,Firstly) because I am convinced that the standards created for Boats,are a superior paradigm than those found on a typical rv,(after all it's life or death not a call to roadside assistance). And Secondly)because I am hands down,shut my mouth astonished at the general quality of info posted on this forum,as opposed to other places. Rooney
I bought my Chinook,then,somewhat like Vivien Leigh(in A Street Car named Desire) relied on the expertise of Strangers,First) The original electrical engineers at TrailWagons Second)The other members of a Users Group (like this one) So I can appreciate inquiring minds,questioning.
Not every post,here (or there) is worth following ( even my own ).When I say a particular setup,works for me splendidly,I should qualify that by saying "it has so far" 2 years of positive use does not constitute success.
I suppose I also subscribe to the idea of "part science part art"when it comes to charging batteries.I read a good deal on the internet about batteries,when after buying my rig and taking my first trip,I heard the low battery alarm.I shook my fist at the sky and swore (This time like Vivien Leigh in Gone With the Wind)"I will never be without battery power again"
All of the experts I read whose posts educated me on the mysteries,and confusion surrounding battery charging,universally deferred to the quality and veracity of the info posted on The Trojan battery,and Lifeline battery websites......
Instead of setting up my own lab like Edison or Tesla,and letting the sparks fly in my lab coat and wild hair,I decided to accept the value of what was posted there.
I started my own inquiry by reading a reference to Handybobs Solar blog buried deep in the archives of the other chinook group...I googled it,read it and went from there.
I want to tread softly,in any of my dissent here,Firstly) because I am convinced that the standards created for Boats,are a superior paradigm than those found on a typical rv,(after all it's life or death not a call to roadside assistance). And Secondly)because I am hands down,shut my mouth astonished at the general quality of info posted on this forum,as opposed to other places. Rooney
-
HereComesTrouble
- Posts: 28
- Joined: June 19th, 2016, 9:16 pm
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
Hello Blue. Haven't posted back in a while. Too many projects going on at the same time. Getting ready to pull the trigger on that morningstar MPPT 15L, the remote meter and the remote temp sensor with cable for $305.09. Just wondering where and how you mounted this unit (a picture would be most helpful.) I have no idea how much heat it generates so, I hesitate to put it under the dinette seating, which would be closest to the battery bank on the passenger side. I'm concerned that items stored in that compartment might interfere with proper air circulation. Next thought was to place it behind the passenger seat on the back of the lower portion of the dinette seat. However, I'm wondering about the cooling fins sinking into the fabric and reducing the airflow. Maybe, I should place a piece of aluminum plate there first. Is there any way to flush mount so, this doesn't look like a growth on the wall? Any and all recommendations are appreciated. - TroubleBlue~Go wrote:Sounds like we basically do the same thing: Have a highly programmable and temperature compensated solar controller (i.e. solar charger), it charges the batteries to 100% about 99% of the time, and the other 1% we use other means.
In my case I do have a similarly good 110 volt charger (programmable, temperature compensated) but... I haven't once used it. If I were to do it over again, given my usage pattern, I wouldn't even buy it. But then I don't tend to plug in or use the generator. If I did, it would charge my batteries just as "correctly" as the solar controller does.
Instead, for the two days in the past year that I have needed a little more charging, I have turned on the switch that combines my alternator/start battery with the house bank, and let that charge things up (less precisely, but workably). With the Scan Gauge, I can see that the voltage coming from the alternator varies between about 13.6 and 14.1 volts on my rig. It works for the bulk charge, which is fine for helping the solar panels from time to time.
And really, once I put my roof solar panels on, I don't see myself needing even that but once in a blue moon. Reason is that it's never that my solar panels can't keep up with my use; but rather it is because since I only have ground panels right now, they are not set out when I'm driving, and/or when I'm in say, a Wal-Mart parking lot, or if I'm stopping for just one night (lazy). Once I have roof panels I don't see needing the alternator charge (but I'll keep the switch in place, in case I want to use it that way and/or for self jump starting).
It might vary for others (less sunny climate, like to use generator/110 loads and charging).
One note on the alternator charge voltage: If you still have the stock wire connecting the two (I think it was 6AWG), there will be a fair amount of voltage drop, so what you see on something like a Scan Gauge will not actually be getting to the batteries. Also, the stock type of separator (e.g. Sure Power 1314 or 1315 is of a type that induces some voltage drop by virtue of its construction (vs. something like a Blue Sea 7622 that does not induce a voltage drop). Just something to keep in mind vis-a-vis alternator charging voltage.
I replaced my separator with a switch, since 99% of the time I *don't* want the alternator charging the AGM house bank. This way I only switch it "on" once in a blue moon (charging help, and/or self jump starting). This amounted to three days over the past year, for example. I have two small LED lights wired to the switch that come on when it is in combined position ("on"). One is a green light by the dash, and the other is a flashing red light in the coach. This way I don't forget and leave it combined (but as mentioned, I leave it "off" 99% of the time).
If I wanted them to automatically combine all the time by default, then I'd put in a Blue Sea 7622.
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
Hi,
I have mounted a couple of these (one in my Chinook, and one in a friend's van). While they do/can generate heat, it's not like they are burning hot, in my experience. Each time I mounted them on a hard surface. I also placed some washers behind them so that they stand slightly proud of the surface. Why not let a little bit of air flow behind them, I figured.
In the Chinook I moved my batteries to under the couch, where they are in a battery box I made. The controller is mounted to the outside "wall" of the battery box. So it's very close to the batteries (good), but not right in with them or over them (would be bad). I have around 5" below and above the controller. I don't store anything in such a way that it could fall on the controller (one could put something like hardware cloth or etc. around it if that were a risk). By the way, the meter will show the temperature of the controller. Mine is rarely above "room temperature" - or not by much anyway. Not that you want to dismiss heat dissipation, but it probably won't be hot enough to fry eggs, based on my experience. I have never had an overtemp alarm (it keeps data).
Since the output of the controller is between 13 and 14 volts (or so), it's good to have it as close as possible to the batteries. If you have it further away, that can work too, but the cables would have to be a lot thicker to keep to the same level of voltage drop. I try to keep that leg especially under 1%. Why throw away power, is my feeling, and plus you want the very specific voltage that you paid good money for your controller to produce to get to the batteries at the specified level. (On the leg of wiring from the panels to the controller, if you have voltage drop you are throwing away power, but NOT changing the voltage that your batteries see, since that power just never even gets to the controller. But on the leg from the controller to the batteries, any voltage drop will reduce the precision of the voltage the controller is trying to send to the batteries.)
Since the landing points on the controller will only take up to 10AWG ring terminals (this is a common fault with controllers, I find), you have a couple of choices in the wiring going to the controller (since 10AWG will probably mean too much voltage drop, depending on your setup). You can go right to the controller with a large wire, then "whittle it down" a bit to make it fit into a 10AWG (yellow) ring terminal (then heat shrink over that). Or you can go to a power post of sorts and step down there. That may work out nicely if you already want a switch or a fuse there. So a lot depends on how things lay out.
The meter can be far away and that's no problem.
Does that help? If not, or if I missed something, just shout (I think your battery layout may not be the same as the older Chinooks).
BG
PS: When you are setting up the controller with the custom set points (at least all the batteries I have had required them because something was always not correct with the default choices), there is one setting that is easy to overlook. This is the rate of temperature compensation. For Lifelines, the default was not correct so I had to change it. What I mean by this is that for every degree over or under 77ºF, the controller will change the voltage by X amount. The X factor in the default settings was not the one Lifeline wants. It's easy enough to change, but also fairly easy to miss.
I have mounted a couple of these (one in my Chinook, and one in a friend's van). While they do/can generate heat, it's not like they are burning hot, in my experience. Each time I mounted them on a hard surface. I also placed some washers behind them so that they stand slightly proud of the surface. Why not let a little bit of air flow behind them, I figured.
In the Chinook I moved my batteries to under the couch, where they are in a battery box I made. The controller is mounted to the outside "wall" of the battery box. So it's very close to the batteries (good), but not right in with them or over them (would be bad). I have around 5" below and above the controller. I don't store anything in such a way that it could fall on the controller (one could put something like hardware cloth or etc. around it if that were a risk). By the way, the meter will show the temperature of the controller. Mine is rarely above "room temperature" - or not by much anyway. Not that you want to dismiss heat dissipation, but it probably won't be hot enough to fry eggs, based on my experience. I have never had an overtemp alarm (it keeps data).
Since the output of the controller is between 13 and 14 volts (or so), it's good to have it as close as possible to the batteries. If you have it further away, that can work too, but the cables would have to be a lot thicker to keep to the same level of voltage drop. I try to keep that leg especially under 1%. Why throw away power, is my feeling, and plus you want the very specific voltage that you paid good money for your controller to produce to get to the batteries at the specified level. (On the leg of wiring from the panels to the controller, if you have voltage drop you are throwing away power, but NOT changing the voltage that your batteries see, since that power just never even gets to the controller. But on the leg from the controller to the batteries, any voltage drop will reduce the precision of the voltage the controller is trying to send to the batteries.)
Since the landing points on the controller will only take up to 10AWG ring terminals (this is a common fault with controllers, I find), you have a couple of choices in the wiring going to the controller (since 10AWG will probably mean too much voltage drop, depending on your setup). You can go right to the controller with a large wire, then "whittle it down" a bit to make it fit into a 10AWG (yellow) ring terminal (then heat shrink over that). Or you can go to a power post of sorts and step down there. That may work out nicely if you already want a switch or a fuse there. So a lot depends on how things lay out.
The meter can be far away and that's no problem.
Does that help? If not, or if I missed something, just shout (I think your battery layout may not be the same as the older Chinooks).
BG
PS: When you are setting up the controller with the custom set points (at least all the batteries I have had required them because something was always not correct with the default choices), there is one setting that is easy to overlook. This is the rate of temperature compensation. For Lifelines, the default was not correct so I had to change it. What I mean by this is that for every degree over or under 77ºF, the controller will change the voltage by X amount. The X factor in the default settings was not the one Lifeline wants. It's easy enough to change, but also fairly easy to miss.
1999 Concourse
-
HereComesTrouble
- Posts: 28
- Joined: June 19th, 2016, 9:16 pm
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
I want to make certain I've chosen all of the correct components before I start to make any purchases. Interested in opinions of the Blue Sky 3000i in comparison to the Morningstar. As I see it, the nice thing about the Blue Sky is, it could easily be blended into the location of the original unit and not look like an afterthought, like the Morningstar.
My 2 batteries are located in the left half of an exterior drawer located on the passenger side and just aft of the propane tank. There is enough room in the front half of that drawer for 2 more batteries if desired. Also, is there a trick to removing that drawer? One side acts like it will come out but the other side acts like there is a stop installed like a normal drawer slide.
It also appears that Grape GS-S-100-TS solar panels are no longer available. They seemed to have been the narrowest panel and, would only overhang the top tier of the wedding cake by about 2 inches. Lengthwise, they also allowed an upgrade from 200 watts to 400 watts if needed in the future. I would love to know if there is anything as compact or more compact with a frame, available today (at a reasonable price) Suggestions appreciated.
My 2 batteries are located in the left half of an exterior drawer located on the passenger side and just aft of the propane tank. There is enough room in the front half of that drawer for 2 more batteries if desired. Also, is there a trick to removing that drawer? One side acts like it will come out but the other side acts like there is a stop installed like a normal drawer slide.
It also appears that Grape GS-S-100-TS solar panels are no longer available. They seemed to have been the narrowest panel and, would only overhang the top tier of the wedding cake by about 2 inches. Lengthwise, they also allowed an upgrade from 200 watts to 400 watts if needed in the future. I would love to know if there is anything as compact or more compact with a frame, available today (at a reasonable price) Suggestions appreciated.
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
Good move to make sure your whole "kit' fits together well and to think about potential expansion. I'm not a big fan of the 3000i for a few reasons, but the main one is that because it's an "all in one," in order to be able to see the display, you are forced to put the controller a long way from the batteries. This is a big downside because voltage drop between the controller and the battery bank is a big negative, and the way around it (if the display were up where you show it) would be to use LARGE wire. Large, heavy, expensive wire. Now don't get me wrong, I'll use 4/0 wire where needed, but in this case why?
I can see wanting it where the original was, but I'd find something else to put there (built in cubby?) if it were me (actually, it was me, and I filled that hole in with fiberglass, plus cut out the TV/VCR holes to make a large square cupboard matching the one on the TV side. Not that I'm saying you should do that.
So anyway, I have my controller about 2' from the batteries, and that's a good distance. With it up where the original was, you'd be looking at something like 12-15'. Ouch. It IS doable though, and if you measure (I use a hunk of rope) and let me know just how long it is, I could let you know what size wire you'd need to keep a low voltage drop. Of course if you later add panels, then you'd have to have even larger wire (more amps going from controller to battery).
IIRC, there are some other limitations to the 3000i. I researched it when I set up and installed a 300 watt system on a friend's van. I don't remember all the other things though because that one thing (distance) stopped us from using it.
You can get panels that are almost exactly the GS100 panels (I have two of the GS100's from a couple of years ago). They are now the Eclipse panel from Renogy. The only difference I see is the frame is black not silver, and they mentioned something about thicker glass adding a couple of pounds (I don't see the need, but the size of those panels is KEY). They are around $200-$225 apiece. They are different than the usual Renogy 100 watt panel which is larger.
If you think you will be adding two more panels, then you have some decisions to make (or not make) now. Basically something like the Morningstar Sunsaver 15 MPPT will handle 200 watts (or a bit more if flat on the roof, but never 400 watts). Two identical controllers with same panels should "play nice" together, but in some ways one controller is better. When I researched all the controllers I could, I found that they all had something I didn't like and there was no perfect one. But you have to choose your flaws
For my current 200 watts, the Sunsaver has been great. The only bad points are that you need a Windows computer (or emulator) to program it and to look at the extensive log files, and that the display only shows one thing at a time. Despite that it's a great controller.
So now I'm going to have 200 watts on the ground (what I have now) and then add two panels to the roof. Not that I need 400+ watts, but I want roof panels so that I don't have to put out the ground panels on quick stops, plus they will work when I'm driving. OTOH, I don't want to give up ground panels, because I love to park in the shade and they are easily tilted as well. So I'm going to have some of each.
So, options:
1) Buy another Sunsaver 15 MPPT. Easy, and they are a good controller. I like that it takes ring terminals. If one goes south, all my eggs are not in one basket. But, I'd need another display (they are not able to both run on one display like their bigger sisters are). Also, although two should play nicely together, it's still not one.
2) Buy one or two Blue Sky controllers and their IPN remote. Plusses are that they can be programmed right from the remote, the remote is set up such that it makes the two controllers play as one (for real not just side by side), and (if one doesn't already have one, but I do) the remote is also a battery monitor (coulomb counter type). And they have good ways for the controller to control the charging (end amps, etc.) But of course none are perfect. Blue Sky seems to favor lower voltage setups (i.e. parallel) so I'd be running right on the edge of their voltage limits (I have my panels set up in series). I also dislike how they have their terminals (really hard to get anything larger than tiny wires into them). And it'd be expensive for me since I'd be buying one small and one larger controller (to handle the voltage) plus the fancy remote (when I already have a battery monitor). But if those things don't apply to you, you could check them out. You could potentially run two 15 amp ones (one for now) and one IPN remote.
3) Buy one controller that can handle it all. Such as the new Morningstar MPPT 40. Plus is that it can be programmed right from the very nice display, can handle all the voltage one can throw at it, and they just make great controllers. Negative is they don't have a remote display for this controller, so you'd have to be bending down into a compartment to see it. Boo! The old MPPT 45 is huge, and needs Windows again, but does have a remote display.
Victron makes some really slick solar controllers (and battery monitors and inverters and etc. etc.). I love their overall company vision. BUT, I had to rule their controllers out because they don't have remote temperature compensation. It's only built into the controller. Even though my controller is less than 2' from the batteries, it's ALWAYS a different temperature (the Sunsaver monitor shows both temps). So my charging voltages would be off. Too bad because they are great otherwise.
Something I alluded to above is running panels in series or parallel. The conventional wisdom on RV's has always been to run in parallel. This means the amps add up and the voltage stays the same (on the way from panels to controller). The plus is that if one panel is shaded, the other still works. The minus is that with lower voltage running along the wires, they have to be thicker for the same distance.
Running in series the voltage adds up, and the amperage stays the same (either way the controller sorts it out so what comes out of the controller is the correct voltage either way). Now you can run much thinner wires (or the same wires longer distances in the case of ground panels). Also I think (but have not proven) that the higher voltage might net you a bit more power earlier and later in the day. I ran some experiments and still did okay withe one panel shaded, so for me the benefits outweigh the negatives. Also on the ground panels this allows me to have 35' of 8AWG wire, and still have very minimal voltage drop. I'd be running garden hose if they were in parallel.
On the roof? Less of a huge plus to running in series, but still nice to have two 10AWG wires coming in vs. four 8AWG ones (or two 6AWG and a combiner box on the roof). So I'm going to try my roof panels in series first. Why am I mentioning this? Because it relates to expansion. IF I wanted to run my roof panels and parallel and my ground panels in series, then I'd have to have two controllers, not just one big one. This may not affect you.
On the other hand, if 200 watts turns out to be enough, you'd be sitting pretty with the Sunsaver 15 MPPT. And you *could* add another one if you wanted to. Or go with two Blue Skys. This allows you to not have to buy a huge controller now.
Either way, I wouldn't go with the "all in one" controller such as the 3000i. The run from controller to battery would just be too long (or huge/heavy) for me. Also I don't think it's very expandable. And not sure you could run panels in series (I forget since I ruled it out for the other reason). Also one thing to do with Blue Sky is read the fine print. Many of their controllers are rated for X amps, but then if you have this or that other factor, they reduce the rating. Just something to read up on.
BTW, most Chinooks (Concourse and Premier) have the batteries on the driver's side under the water heater, starting around 1997. So basically under the front of the couch, only beneath the floor. I know they changed the compartments around at the very end (say 2005-2006) so that's why yours are on the passenger side. So our stock solar wire run was REALLY long from that controller!
I'm sure not all of this made sense, so feel free to keep replying
I can see wanting it where the original was, but I'd find something else to put there (built in cubby?) if it were me (actually, it was me, and I filled that hole in with fiberglass, plus cut out the TV/VCR holes to make a large square cupboard matching the one on the TV side. Not that I'm saying you should do that.
So anyway, I have my controller about 2' from the batteries, and that's a good distance. With it up where the original was, you'd be looking at something like 12-15'. Ouch. It IS doable though, and if you measure (I use a hunk of rope) and let me know just how long it is, I could let you know what size wire you'd need to keep a low voltage drop. Of course if you later add panels, then you'd have to have even larger wire (more amps going from controller to battery).
IIRC, there are some other limitations to the 3000i. I researched it when I set up and installed a 300 watt system on a friend's van. I don't remember all the other things though because that one thing (distance) stopped us from using it.
You can get panels that are almost exactly the GS100 panels (I have two of the GS100's from a couple of years ago). They are now the Eclipse panel from Renogy. The only difference I see is the frame is black not silver, and they mentioned something about thicker glass adding a couple of pounds (I don't see the need, but the size of those panels is KEY). They are around $200-$225 apiece. They are different than the usual Renogy 100 watt panel which is larger.
If you think you will be adding two more panels, then you have some decisions to make (or not make) now. Basically something like the Morningstar Sunsaver 15 MPPT will handle 200 watts (or a bit more if flat on the roof, but never 400 watts). Two identical controllers with same panels should "play nice" together, but in some ways one controller is better. When I researched all the controllers I could, I found that they all had something I didn't like and there was no perfect one. But you have to choose your flaws
For my current 200 watts, the Sunsaver has been great. The only bad points are that you need a Windows computer (or emulator) to program it and to look at the extensive log files, and that the display only shows one thing at a time. Despite that it's a great controller.
So now I'm going to have 200 watts on the ground (what I have now) and then add two panels to the roof. Not that I need 400+ watts, but I want roof panels so that I don't have to put out the ground panels on quick stops, plus they will work when I'm driving. OTOH, I don't want to give up ground panels, because I love to park in the shade and they are easily tilted as well. So I'm going to have some of each.
So, options:
1) Buy another Sunsaver 15 MPPT. Easy, and they are a good controller. I like that it takes ring terminals. If one goes south, all my eggs are not in one basket. But, I'd need another display (they are not able to both run on one display like their bigger sisters are). Also, although two should play nicely together, it's still not one.
2) Buy one or two Blue Sky controllers and their IPN remote. Plusses are that they can be programmed right from the remote, the remote is set up such that it makes the two controllers play as one (for real not just side by side), and (if one doesn't already have one, but I do) the remote is also a battery monitor (coulomb counter type). And they have good ways for the controller to control the charging (end amps, etc.) But of course none are perfect. Blue Sky seems to favor lower voltage setups (i.e. parallel) so I'd be running right on the edge of their voltage limits (I have my panels set up in series). I also dislike how they have their terminals (really hard to get anything larger than tiny wires into them). And it'd be expensive for me since I'd be buying one small and one larger controller (to handle the voltage) plus the fancy remote (when I already have a battery monitor). But if those things don't apply to you, you could check them out. You could potentially run two 15 amp ones (one for now) and one IPN remote.
3) Buy one controller that can handle it all. Such as the new Morningstar MPPT 40. Plus is that it can be programmed right from the very nice display, can handle all the voltage one can throw at it, and they just make great controllers. Negative is they don't have a remote display for this controller, so you'd have to be bending down into a compartment to see it. Boo! The old MPPT 45 is huge, and needs Windows again, but does have a remote display.
Victron makes some really slick solar controllers (and battery monitors and inverters and etc. etc.). I love their overall company vision. BUT, I had to rule their controllers out because they don't have remote temperature compensation. It's only built into the controller. Even though my controller is less than 2' from the batteries, it's ALWAYS a different temperature (the Sunsaver monitor shows both temps). So my charging voltages would be off. Too bad because they are great otherwise.
Something I alluded to above is running panels in series or parallel. The conventional wisdom on RV's has always been to run in parallel. This means the amps add up and the voltage stays the same (on the way from panels to controller). The plus is that if one panel is shaded, the other still works. The minus is that with lower voltage running along the wires, they have to be thicker for the same distance.
Running in series the voltage adds up, and the amperage stays the same (either way the controller sorts it out so what comes out of the controller is the correct voltage either way). Now you can run much thinner wires (or the same wires longer distances in the case of ground panels). Also I think (but have not proven) that the higher voltage might net you a bit more power earlier and later in the day. I ran some experiments and still did okay withe one panel shaded, so for me the benefits outweigh the negatives. Also on the ground panels this allows me to have 35' of 8AWG wire, and still have very minimal voltage drop. I'd be running garden hose if they were in parallel.
On the roof? Less of a huge plus to running in series, but still nice to have two 10AWG wires coming in vs. four 8AWG ones (or two 6AWG and a combiner box on the roof). So I'm going to try my roof panels in series first. Why am I mentioning this? Because it relates to expansion. IF I wanted to run my roof panels and parallel and my ground panels in series, then I'd have to have two controllers, not just one big one. This may not affect you.
On the other hand, if 200 watts turns out to be enough, you'd be sitting pretty with the Sunsaver 15 MPPT. And you *could* add another one if you wanted to. Or go with two Blue Skys. This allows you to not have to buy a huge controller now.
Either way, I wouldn't go with the "all in one" controller such as the 3000i. The run from controller to battery would just be too long (or huge/heavy) for me. Also I don't think it's very expandable. And not sure you could run panels in series (I forget since I ruled it out for the other reason). Also one thing to do with Blue Sky is read the fine print. Many of their controllers are rated for X amps, but then if you have this or that other factor, they reduce the rating. Just something to read up on.
BTW, most Chinooks (Concourse and Premier) have the batteries on the driver's side under the water heater, starting around 1997. So basically under the front of the couch, only beneath the floor. I know they changed the compartments around at the very end (say 2005-2006) so that's why yours are on the passenger side. So our stock solar wire run was REALLY long from that controller!
I'm sure not all of this made sense, so feel free to keep replying
1999 Concourse
-
HereComesTrouble
- Posts: 28
- Joined: June 19th, 2016, 9:16 pm
Re: HELP!!! AGM Batteries (DUMB QUESTION & RANT)
Thanks for your very thoughtful and detailed response. Generally speaking, I think you are probably correct. Two 100 Ah batteries will most likely meet all my needs. My previous RV was a 21 footer with only one house battery and I never really had a problem with running short on power unless we were using the furnace at night. The solution there was to set the thermostat to 55 degrees and bundle up.
I hadn't thought about doubling up on controllers for my solar if needed. It sounds like Morningstar has won this round. The last item I'm trying to decide on is the charger/converter that runs off of shore power. I would prefer one that has a remote panel as my charger is a floor mounted, standalone unit that sits back under the galley cabinet and is bolted to the wheel well. It plugs into an AC outlet in the back of the AC panel, which is under the drawers in the galley base cabinet.
By the way, the real reason my batteries are on the passenger side is, mine is a Destiny, not a Concourse or a Premier. The pictures below are not of my RV but, ones I found online.
I hadn't thought about doubling up on controllers for my solar if needed. It sounds like Morningstar has won this round. The last item I'm trying to decide on is the charger/converter that runs off of shore power. I would prefer one that has a remote panel as my charger is a floor mounted, standalone unit that sits back under the galley cabinet and is bolted to the wheel well. It plugs into an AC outlet in the back of the AC panel, which is under the drawers in the galley base cabinet.
By the way, the real reason my batteries are on the passenger side is, mine is a Destiny, not a Concourse or a Premier. The pictures below are not of my RV but, ones I found online.