Batteries and Charging

[Blue~Go]

I just looked up the IP21 300a Smart Shunt. Notes, some important:

#1 I think disqualifies it for your purpose, which is that it does not have a programmable alarm, at all. (I can guess this is because they figure you will be using it with a full Cerbo GX big/fancy type system, wherein you would get alarms that way vs. directly from the Smart Shunt.) I had wrongly thought that it would have the ability to have an alarm connected to it directly.

#2 The temp sensor looks exactly the same as the BMV 712 to me in terms of how it connects. Two pins snap into the clicky terminals on the shunt, and a lug goes on a battery post.

#3 I think the size is a bit of a wash, because while the bare shunt would be slightly smaller than the 712's shunt, it has the "hunka" smart blue thing stuck to the side of it whereas the 712 shunt does not.

But the main thing to me is #1. You definitely want an alarm function. This will be a better, smarter, adjustable, customizable LVD in a sense.

I have attached data sheets for both, and have highlighted the alarm/lack of alarm.

Note that there is nothing on the BMV 712 -- including the temp sensor -- that is not "plug and play." I mean except that you will be attaching battery lugs, but that's the same for both flavors.

brown box Datasheet-SmartShunt-EN.pdf

(536.42 KiB) Downloaded 147 times

brown box 2025 Datasheet-BMV-712-Smart-EN.pdf

(526.88 KiB) Downloaded 129 times

PS: Just in case you are bumming out, thinking "Oh but that Smart Shunt was going to be so small and tidy in the battery compartment!" The 712 shunt is basically exactly the same size.

Dimensions of the two, compared:

Smart Shunt IP22 300a shunt
4.72" long x 1.73" wide x 1.73" tall

BMV 712's 500a shunt:
4.72" long x 1.75" wide x 1.71" tall

Granted you will have the display head, but that's not going to be located in the cramped battery compartment, but rather somewhere in the Chinook, so you can hear (and interact with) the alarm. I don't actually have mine mounted, but rather it's zip tied in the overhead compartment, over on the driver's side (there are some Chinook wire looms there where I have it secured but can still pull it out). It could go pretty much anywhere you like as the "phone cord" is 32.8' long (you can buy shorter ones - and probably longer ones; but this is the one that comes with it).

Reason I don't have mine mounted in a dedicated hole is that I usually interact with it via Victron Connect. Except if the alarm goes off: Then I reach up and press a button to turn it off. BTW, you can still see alarms in Victron Connect. I'm actually not sure whether or not you can turn them off via the App -- I've never tried it because the few times it has gone off it's been the proverbial 3 a.m. and it was easier to reach out and thwack the 712 display than to fire up my phone, open the app, wait for it to connect, etc.



The temp sensor you want is Victron part number ASS000100000. This same temp sensor part number goes with both the 712 and the Smart Shunt IP22 300a, hence them both having the same "plug and play" connection for it.

[deppstein]

OK...here we go! I believe we have gotten to the Center of the Circle. It's been a long and winding road indeed, but I think all of the pieces of this project have fallen into place for me. Blue...GREAT THANKS for your guidance (and patience). I think I now know how to move forward with all aspects of this "Battery/Charging" Project in a way that puts me in that Laser, up on a plane, screaming at the top of my lungs due to the thrill of it all!
I've got it all clear in my head about the new chargers--Orion XS and IP22 12/30--how the IP22 will go to outlet on old PD4645 breaker (with new wiring), and the Orion XS with its new pair of 4awg wiring. I also understand the process that I will use to identify what wires are what, cut the chaff from the wheat, and use the Blue Sea Safety Hub and Victron Shunt to tie things together. Along the way, I will bypass the LVD (fare thee well!) and get rid of the 150 fuse on the Inverter. I'll use wire (instead of solid) link between Hub and Shunt...and use all gauge wiring for things as has been discussed. The only deviation from what you have suggested is still my plan to use 4awg to connect Hub to Shunt...space dictates that I keep these as close to each other as possible, and 4 awg makes it easier to do that than 1/0. It is sufficient, and (I believe) consistent with the "loop" it belongs to.
So, let's jump to the last piece of the puzzle...using the BMV 712 instead of the Smart Shunt 300. Why did I hesitate?...well, for one thing, the Smart Shunt had the "Load" terminal on the left (where I need it), and the BMV has it on the right. OK David...flip the BMV Shunt around--so what that it will be "upside down"! I can manage that. Then there was the issue of the low voltage alarm...to wire separate, or take Blue's advice and use the built in buzzer feature of the BMV...The trouble with this was that I was getting conflicting information from Chat GPT vs. what Blue was telling me...should have guessed...Blue is indeed smarter than Chat GPT!!! Chat decided to be less than truthful here--telling me at first that I would need an external buzzer alarm even with the BMV....Turns out, that is JUST NOT TRUE...which I discovered by continuing to refine my questions. In doing so, Chat finally admitted that (get this!) they did not tell me about the built in buzzer because they thought it would be too soft for my needs! Unbelievable! And, I dare say, a lesson for us all. Don't take what Chat has to say as the Gospel. In Blue Go we Trust!
Anyway, all's well that ends well. And Blue, if I am still missing something, be sure to let me know...otherwise, on to implementation.
David

[Blue~Go]

OK...here we go! I believe we have gotten to the Center of the Circle. It's been a long and winding road indeed, but I think all of the pieces of this project have fallen into place for me. Blue...GREAT THANKS for your guidance (and patience). I think I now know how to move forward with all aspects of this "Battery/Charging" Project in a way that puts me in that Laser, up on a plane, screaming at the top of my lungs due to the thrill of it all!

Sweet. No "Snark" for you That said, I'm just going to let go the sheet for for a minute and let us luff while we iron out a couple more things.

I've got it all clear in my head about......
Along the way, I will bypass the LVD (fare thee well!) and get rid of the 150 fuse on the Inverter. I'll use wire (instead of solid) link between Hub and Shunt...and use all gauge wiring for things as has been discussed. The only deviation from what you have suggested is still my plan to use 4awg to connect Hub to Shunt...space dictates that I keep these as close to each other as possible, and 4 awg makes it easier to do that than 1/0. It is sufficient, and (I believe) consistent with the "loop" it belongs to.

Okay so when you say "get rid of the 150 amp fuse for the inverter," that's because (IIUC) you are going to do two things:

1) Use one of the Safety Hub positions
2) Go with a 100a fuse as I believe Xantrex would recommend for the 1000 watt (as they specced a 150a fuse for my 1500 watt version)

Okay, fine.

But on the second half -- using 4AWG between the SH neg bus/shunt/batt neg post -- I disagree. I will insert a drawing here with an explanation below it.

[But wait.... now that I stare at my drawing an hour later..... maybe there is not a loop there? Ha, the fact that the SH is all one piece makes it weird to think about. So maybe I'm wrong and any current in the "teal" leg would have to have passed through a smaller fuse/positive leg in order to get back around. That said, even so my own personal preference is to have the "equivalent" negative legs always be the same size as the matching positive legs. If nothing else just for the same reason you have a larger "green" initial positive leg than you do the spurs... because that leg -- and the corresponding return leg -- can carry many loads at once, so it's just a good idea. Otherwise why have that first leg be 250a fused 1/0? (We know why.) But okay, so carry on reading with that in mind...]

I posit that the teal colored wires should (also) be 1/0, along with the green ones. Here's why. Look at the "loop" made by the 1/0 positive wire coming from the battery (green arrow) and the return path that I have shown in teal (which I also think should be 1/0).

Let's say there is a short in that teal section of wire. What is fusing it? Answer is the 250a MRBF on the positive battery post. 4AWG only has an ampacity of 160 amps in even the best case scenario. 1/0AWG has an ampacity of 285 amps in the best case and 245 amps in a slightly more conservative case (using the 90ºC rating for 105ºC rated wire). In other words, 1/0 is adequate, but not super generous for a 250a fuse.

Now let's say you go down to a 200 amp main fuse. Then you could make that 1/0AWG loop juuuust barely 2AWG, but that would be even tighter to the ampacity rating. If I were going to go down to a 200 amp fuse, I would still keep 1/0 and just have a more generous safety factor.

I would stick with 1/0 and a 250 amp main fuse. Why? Well that cable is carrying everything. Why whittle it down? In case it helps, I have a 2/0AWG (bigger!) jumper (from the Blue Sea switch to the Safety hub) that is about 3" long. And same in 2/0AWG from the SH neg bus to the shunt load side. You are working with 1/0, which is smaller, so you could make it even slightly shorter. I usually would use a solid link for these shorties, but in this case (for reasons that would just clutter up this post), I wanted to use cable and lugs. Key is that I "pre-curved" the wire (basicallly worked with its natural curve) and then crimped on the lugs also patterning to the bend. I have actually made shorter ones that were literally two lugs with wire in each one and no "body" wire to speak of. Just heat shrink (less curve in those).

So, let's jump to the last piece of the puzzle...using the BMV 712 instead of the Smart Shunt 300. Why did I hesitate?...well, for one thing, the Smart Shunt had the "Load" terminal on the left (where I need it), and the BMV has it on the right. OK David...flip the BMV Shunt around--so what that it will be "upside down"!

Yes, you can unscrew the little circuit board and flip it around. Couple of notes: You may need to slightly trim the edge of the green board. You'll see what I mean (and it doesn't always need it). Also just make sure you can still get the sensor and display head cables clicked into place and back out. What I mean is you can just push on the sensor leads and they will "click" into place, but to remove them you need to push on the little orange levers. Try it before you mount the shunt and you will see what I mean. Not saying you can't do it (I have), but it will be easier to try it and develop a little push stick or whatever you need while it's on the workbench and you can see what you are doing and get a feel for it.

I can manage that. Then there was the issue of the low voltage alarm...to wire separate, or take Blue's advice and use the built in buzzer feature of the BMV...The trouble with this was that I was getting conflicting information from Chat GPT vs. what Blue was telling me...should have guessed...Blue is indeed smarter than Chat GPT!!!

Come, Chat GPT?! Please. And actually it's not a matter of smarts: I simply read the manuals and datasheets for both of them (plus I have used the BMV 712, the BMV700 before that, and even an old BMV600!). It did take me until I went digging for the shunt size info to realize that you CAN'T put a buzzer on the Smart Shunt. That sort of makes sense because the Smart Shunt is kind of made for a fancier system with a Cerbo and all that that entails (which I can't see you wanting). So there would be other ways to have alarms.

Chat finally admitted that (get this!) they did not tell me about the built in buzzer because they thought it would be too soft for my needs! Unbelievable!

Ha ha, mine has gone off at 3 a.m. and I can guarantee it's not "soft." I mean it's not quite "smoke alarm" pierce-your-eardrums loud, but I don't think that's a bad thing. It will still get your attention, IMO. Tho if your hearing is less than it once was, you might set it off on purpose before deciding on its location vis-a-vis your ears.

As I mentioned previously, I don't set mine for the exact "running out" point on my batteries. The LVD was basically set even lower than that, at the "not only have you run out but your batteries are now ALREADY BEING damaged" setting. I like it so that if mine alarms (which is still very rare, because it's easy to keep an eye on the system and you get used to how it functions), it's not like "SHUT IT ALL DOWN NOW!!!" but rather "Carry on, go back to sleep, get up and turn on the furnace and make coffee and have breakfast; then think about how you will go about making sure to put some amps back into the batteries today."

To be clear: The BMV alarm will not shut anything off. It's just letting you know you should do something (or think about doing something, if the alarm is set more conservatively) (There are ways to add gizmos that will actually shut down your loads, if you decide you want those in the future. But BMV alarm is always good to have in any case, so you won't be "throwing anything away" in any case.)

This is a good time to mention that once you have Victron Connect up and running (which you can do now or maybe already have), a great resource is to go into the "Demo Library," which you can choose by going to the upper left hamburger menu in the Victron Connect app. This allows you to go in and see all the settings and mess around with various devices, without doing it on YOUR devices. Or see what a device has to offer before buying it. These things are usually also in the manual but this is a great alternative. Here is the "alarms" page from the Demo Library for the BMV712:

Here you can see that you can set one or more alarms. For my current LFP bank, I use a low SOC alarm. This is due to the fact that LFP voltage is very stable. This is great for actually using the batteries, but not so good for using voltage to set an alarm. There's just not enough voltage variation.

But SOC can drift over time due to various factors. So with an AGM bank I think I would use voltage for my "low" alarm. Set it to perhaps 12.2v or thereabouts. OTOH, perhaps your inverter will cause too much voltage sag for that with lead acid batteries. If that's the case, you can go with low SOC % instead.

A tip on SOC: Besides making sure you get the intial parameters set correctly, you can also manually sync it to 100% anytime you KNOW the batteries are at 100%. You can do this in the VC app, or you can also do it by pressing and holding the + and - buttons on the display head simultaneously for a couple seconds. This helps keep it accurate.

Also, as your AGM batteries age, if you want SOC to stay accurate, you will want to reduce the capacity of your bank. This is a bit of a guess of course. But essentially if you start with say 200ah, but then two years later your bank's capacity is down to 160ah, then your baseline has changed. So your SOC would be all wrong, as it would be calculating percent based on a 200ah bank. Changing the bank capacity (easy in the app) will coordinate things again.

Good thing is all of this is easy to change right from your phone. It's not like ye olden days where you had to open up some obtuse program or squint at dip switches or numeric codes that meant something you had to look up and decipher (even the BMV 600 still had those). "Hmm, what is 'L4'....?"

BTW, I was just thinking that.... once you have all this done, you would almost be able to "drop in" LFP batteries. One big reason "drop in" isn't usually real is that typically there are a bunch of other things in the overall DC distribution system that would need to be upgraded. Now, don't just throw in LFP without going over a few things, but just off the top of my head you would be ready - or darned close to it if not.

(For example, depending on the capacity of the LFP battery(ies), you might need to exchange an MRBF for a Class T main fuse - or maybe not, just depends on specs.)

Hmmm, bought those AGM's yet?

[deppstein]

...Good idea to head into irons and luff a bit while we get our bearings and check the rigging. Reading your addendum to the 1/0 loop from SH to Shunt and Batteries, I think we agree that, particularly since the Inverter is not on the SH, I am probably OK with the 4awg connector--but I like your idea of pre-bending and using the ring terminal ends to help the curve along. If I can get everything to fit with the 1/0, I'll use it, with 4awg as back-up plan.
On the elimination of the 150 Inverter fuse--yes you understand correctly.
I also understand that the alarm is just that...not going to shut anything down. And, since I don't sleep with my hearing aids, I will experiment to find a suitable location for the little bugger.
I wondered about making sure the temp sense plugs would fit in configuration I am envisioning--I'll be sure to check all that out before securing things.
I'm thinking that I will go slightly lower than 12.2...but will do more noodling around about that. And, for now, not ready to tackle it based on %SOC--have a lot more reading and learning before going down that road. I haven't begun to play around with the Victron Connect yet. When I do, I'm sure I'll have a whole bunch of new questions!
As for going over to the Lithium side...I really do think that the ship we have built here will be plenty seaworthy for the voyages I am currently contemplating. One thing at a time...but nice to know that all being done here would be useful under Lithium skies.
Onward.
David

[Blue~Go]

Onward indeed.

On the topic of SOC: Once you get everything installed, it's time to set up the BMV (in "Settings" on your phone/tablet/computer). I'd be happy to run through that with you. It can seem intimidating at first, but we can make it "not so" -- and then after that if you want to change the alarm or some other small detail it will just be a little tweak to your baseline rather than having to go through everything again.

A note about the temp sensor: It can actually be used to do one of three things. Temp sense, voltage monitoring of another battery bank, or midpoint voltage sensing. However it can only do one of these things. You will be choosing temp sense, so just know you'll be ignoring the other two.

[deppstein]

I will most certainly take you up on the offer of helping me navigate Victron Connect and the BMV when the time comes. But, that won't be for a while. Eddie says that he will probably squeeze me in for the "install" at the end of April/early May. In meantime, I have begun to do the prep work: --identifying all my wires and capping what I don't need
--putting new terminals on the Start Battery (old one's are terrible!)
--Getting the new Fullriver AGMs...will get them close to install time--pick up at Northeast Battery about an hour from me.
--removing the Blue Sea ARC
--getting the new outlet for the IP22 and 14/3 triplex wire run to breaker all set so I can just swap for PD4645 when time comes
--bypass the LVD with the new 6awg run...making sure that the 6awg will fit onto the existing Distribution Board?!
--figure out how to enlarge the hole from cab (right around where the LVD is) to Battery Box that was made for the 1/0 Inverter cables so I can run the new 6awg Distribution Wire and IP22 AC cable up through there...UNLESS YOU HAVE ONE OF YOUR NEATER/BETTER RECOMMENDATIONS

Blue...thanks again for your help in guiding me through this. Would still be trying to pretend that Snark was a Laser were it not for you! And here's hoping others have benefited from this thread as well.
David

[deppstein]

It's been way too cold up here in New England to do any work outside, so that work (new Start Battery terminals, IDing existing wires into the battery, removal of the Blue Sea ARC) will all have wait. In meantime, I have cranked up the heat in the Rig to do some of inside stuff in preparation for installation of new Batteries, Chargers, Safety Hub, and BMV 712 that my Man Eddie will be doing. Here's a rundown:
--got a flush mounted outlet and wired it with 14/3 that runs behind the couch to the Brown Box. The outlet will mount in LVD location (once LVD is removed).
--Ran new 6awg wire from Distribution Board area behind sink, behind couch to the hole (leading to battery compartment) that was made for the inverter wires...there is room enough for the 6awg as well...nice bonus. Then I can repurpose the hole that currently takes the old 8awg to batteries for the BMV wire from Shunt to Display. I've decided to velcro the Display to the top of the "triangle thingie" that covers the LVD (and will cover the new outlet)...FYI, I discovered that the Distribution Board will not take anything larger than 8awg coming in from the batteries--so I will use a step-down straight connector (6awg to 8awg) to attach a short run at end of this line to the Distribution Board. Now that I have gotten my sea legs, I've decided to make as many of my own wires for the project as I can... cutting wire, using ferrules, making ring terminals, crimping, and heat shrinking. Growing my tool box and learning new things!
...some pics of the "work in progress" attached.
David

[deppstein]

I'm back with a question about how to get the best temperature sensing for charging from the batteries in the case of my build (Orion XS and IP22). I was planning on using the remote temp sensor attached to the BMV 712's smart shunt for this purpose, but now I have been told by Victron that neither the Orion or the IP22 will be able to automatially adjust temp parameters using that sensor...they simply don't speak to each other. In lieu of that, Victron has recommended that I use their Smart Battery Monitor (bluetooth device has lugs that attach directly to the battery terminals). The IP22 does have bluetooth capability, and therefore is able to connect and use that data to automatically adjust temp charging parameters. The Orion XS, unfortunately, does not (nor does any other Victron DC-DC charger). But, I can still use the actual temp readout I get from the Smart Battery Monitor via the network to manually set the Orion charging parameters based on the real battery temp. This seems like a reasonable way to proceed--especially since the Orion XS does have internal temp sensing I can fall back on...which is much better than what I have now.
But, I'm definitely on the steep learning curve here, so would like to hear what others think. As always, any and all comments welcome.

Also, I haven't settled for sure on the location of the IP22...in the big outside compartment, or somewhere inside. I believe that I understand the pros and cons/work required for each, etc. Just haven't decided on which way I want to go.
David

[deppstein]

Working on my electrical upgrade and in need of some advice. What should I do with the wires coming into the battery box (see pictures) that I no longer need? I have identified the ones to keep, but what should I do with that mess of others coming in from the left? Cut and cap them from the underside where they come into the box?

And does anyone know of a way in which I can use the old 2 awg wire that went from the Blue Sea ARC inside the engine bay to the Battery Box as a snake of some kind to find a good path for the new set of 4 awg wires that will now run from the Start Battery to House Battery Box?

Any and all help welcome.
David

[Blue~Go]

FYI, I discovered that the Distribution Board will not take anything larger than 8awg coming in from the batteries--so I will use a step-down straight connector (6awg to 8awg) to attach a short run at end of this line to the Distribution Board.

Just as another option: If 8AWG has the ampacity to cover your main fuse (that's going to fuse the 6AWG run from the Safety Hub to the brown box - sorry I forget what size fuse you are using), you *could* just nip a few strands off the 6AWG. I know that sounds like a huge cheat, BUT..... a bunch of unneeded joints isn't great either, and IF the 8AWG has the ampacity (or you fuse to meet that), then you are only running the 6AWG for voltage drop (usually the case in 12-volt systems). Having 3/4" of 8AWG won't materially affect voltage drop in the slightest.

As I remember it, the brown box has one of those "shove it in and screw it down" sort of connectors. You could consider using a ferrule, but that's independent of making it small enough to go in the hole.