Battery separator for lithiums

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FatBuoy
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Battery separator for lithiums

Post by FatBuoy »

I believe I'm going to go lithium on the coach batteries. I may swap the AGMs to the other one, and just figured now is the time. There are so many advantages. The long-term ROI is there, they are lighter and the actual usable capacity far exceeds all of the other solutions.

My Progressive Dynamics charger/converter has the ability to accommodate them, so I'm good there. I'm not itching to do a big solar build, for now, so not to worried about that just yet. But if and when I do, I would just need a different charge controller.

My ask for help- what has anyone done for the battery separator? My understanding is that since the chassis battery would run at a lower voltage than the lithium coach batteries, the stock separator will not function in that capacity.

Is there an easy solution that will just swap out with the stock one? I recall someone building out a very elaborate solar system, with that being a part of it, but I believe everything was rewired under the couch. I don't want to get that involved. I would love a plug and play, or at least something close that would still be mounted under the hood where the stock one is.
2001 Premier aka "Anookie"
Dallas, TX area
chin_k
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Re: Battery separator for lithiums

Post by chin_k »

If you want something easy, just don't put anything for the separator. It is rarely used, esp. if you upgrade to lithium, and you can get a separate lithium jump starter the size of a pencil box to jump start if you really need to. I wonder what other folks think about this "solution."
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
BobW9
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Re: Battery separator for lithiums

Post by BobW9 »

If the coach batteries are lithium, then you can not use the stock engine alternator to charge them while driving. You would need to buy something like a battery-to-battery charger that can get input from the alternator at lead acid voltages and then output to lithium voltages. The B2B will also drive much more current into the lithium than an alternator would, so you can charge faster (but then may need an upgraded alternator to handle the higher current).

If you're not concerned with charging them while driving, then just disconnect the coach system from the cab. This also solves the issue of making sure to not charge the lithium when the battery temps are going to be near or below freezing while you're just driving around. Of course, if you're boon docking you'll then have to run the generator to charge, rather than just making a run to a store or driving around sightseeing.

You'll have to decide whether to keep the batteries outside in an unheated compartment, in which case you'll need a way to keep them warm in winter, and hopefully not super hot in summer if you're out west somewhere. Many people move them inside.

Note that lithium have longer life if they are not kept at or near 100% charge, unlike lead acid.

If you're not changing the solar controller, then make sure to disconnect it so it doesn't try to charge the lithium with the wrong values. Also, as I mentioned above, continually topping off the lithium to 100% via solar always being on is not a great thing for them, so I'd advise a manual disconnect. I'd use a Blue Sea 187-Series Circuit Breaker, as they are fuse and switch combined, and made for switching while hot (many switches are not).
2000 Concourse, Ford Triton 6.8 V10
chin_k
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Re: Battery separator for lithiums

Post by chin_k »

I completely forget about one of the main advantages of the separator is to allow the alternator to charge the batteries while driving. I was only thinking of the boost function when the chassis battery is low.

I think Blue has a great point about the lithium battery characteristic that it does not like to be fully charged all the time. It may not make a lot of difference between having the battery lasting 6 years compare to 10 or more years, but if longevity is a concern, then it will be important to control the state of charge. Some lithium charger allows one to customize the SoC (I usually keep it max at 60% to 80%, unless I know I am heading out and in that case, I will top it off), but the Progressive Dynamics and many other chargers does not have that functionality. I would not want to use my alternator to charge my lithium for the most cases. If I really need to charge it in a hurry, I would fire up my genset and use the dedicated charger to do it at the fast speed. It only take a few minutes for me to get 25% SoC that way, and less wear and tear on my engine/alternator/radiator. It really depends on your specific use case, and what is the setup. For my situation, the extra cost of a separator that works with lithium just not justified by the kind of utility that I can get out of it. YMMV.
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
starjots
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Re: Battery separator for lithiums

Post by starjots »

I upgraded the batteries on our 95 Premier from AGMs to Lithium Iron Phosphates this last winter. In the Premiers, the original house battery is in the engine compartment, but I'd added a second bank under the jack knife couch years ago. The second AGM bank was set up to charge from the alternator and that worked okay.

When I changed out the AGMs to Lithium, I initially tried to use the old alternator charge setup and it basically didn't work. So I added a Victron DC to DC charger (Victron Energy Orion-Tr Smart 12/12-Volt 18 amp 220-Watt DC-DC Charger, Isolated (Bluetooth) $170). Verified on recent trip this charges the batteries quite well while driving getting slightly more than the advertised 18 amps of charge. Better yet, the Victron unit has the correct charge profile and can charge the batteries all the way to full.

As far as the Progressive Dynamics converter (which I installed in 2015 along with the AGM batteries), I upgraded that to their Lithium version. This works with the new lithium batteries, but it seems to rely on the batteries BMS (battery management system) to keep the batteries from getting overcharged. So if I plug in the rig while it's sitting, I usually disconnect (via a switch I installed) the batteries from the charger. I could be wrong about the Progressive Dynamics unit behavior -- I find it easier to control what is charging my batteries when manually.
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FatBuoy
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Re: Battery separator for lithiums

Post by FatBuoy »

Bringing this thread back up.

I bought two Battleborns and a Victron non-isolated DC-DC charger. I chose non-isolated because the batteries share a common ground. That was my thought process.

Should I have gotten the isolated?

IF I bought the right setup, could someone please help with how I connect all of this? The instructions are a bit confusing to me.

Would I just remove the existing isolator and attach the leads that are going into it to the new one? I haven't traced all wires, but it appears that the two positive leads that go into the current isolator would just plug into the Victron. (It has three ports, two for positive and one for negative)

Any help with how to hook this up would be appreciated.

I do have a Progressive Dynamics converter/charger, which has a jumper to prep it for the lithiums.

There's also a little jumper plug on the front of the Victron unit (green)

What is that used for?
2001 Premier aka "Anookie"
Dallas, TX area
chin_k
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Re: Battery separator for lithiums

Post by chin_k »

Sorry, but you may want to contact the vendor if no one chime in. I do not have any Victron product, but my interaction with them seems to indicate that they are knowledgeable and willing to help both current and potential customers. I am sure they will be able to address all of your question.
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
Carolann22
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Re: Battery separator for lithiums

Post by Carolann22 »

I just changed to lithium batteries. Had a Progressive Dynamics PD4645 installed. Rep from Progressive said their product does not need the DC to DC converter. Hope I’m good to go
BobW9
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Re: Battery separator for lithiums

Post by BobW9 »

They are talking about two different things - charging the lithium house batteries via Progressive PD4645 when plugged in on shore power, and charging the lithium house batteries via a DC-DC charger from the engine alternator while the engine is running (driving, or just sitting somewhere idling).

I believe, since the Lithium need a different charging cycle, with different voltages, than lead acid/AGM need, either you need a DC-DC charger that will convert the alternator's lead acid charging to Lithium charging, or you need to disconnect the wire between the engine system and the house batteries (and just not charge when driving). That is the wire that came with the Chinooks that has a battery separator/isolator/solenoid on it (generally, the Surepower 1314/1315).

Oh, and either way, get rid of that 1314/1315, as I believe most Lithium battery manufacturers recommend not jump starting the engine lead acid via a Lithium house battery. The Lithium house batteries are not made for the kind of current surges that occur when starting an engine.
2000 Concourse, Ford Triton 6.8 V10
Claude
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Re: Battery separator for lithiums

Post by Claude »

I've been searching the posts related to battery separators and lithium batteries and stumbled across this one. I don't know if it's appropriate to post my question under this topic, but the discussion here is the closest I've seen to my situation. Here goes:

I am the 4th owner of a 1997 Chinook Concourse SE. A previous owner did extensive electrical work, installing a multiplus compact inverter, solar controller (MPPT 100/50) and a BMV-712 battery monitor (all Victron). The house is powered by a lithium Valence U27-12XP battery. I have since installed 160W of solar and switched all the lights to LEDs and the system is working well. (other than the DC on the Dometic fridge, but that's a whole 'nother story)

For unknown reasons, the toggle switches overhead above the drivers seat were all disabled/disconnected. The Onan generator had been removed for additional storage and a Honda EU2000 is carried onboard in the storage behind the spare tire to be used if needed. Given the way we camp, in over 10K of travel, I've never had to fire it up.

On our first big outing (7800 miles/2 months) I noticed that the house battery was not being charged by the alternator. I tested the separator (Surepower 1315-100 amp) and it is fried. In researching a replacement, I've come across discussions that caution using a separator with a lithium battery (although the BattleBorn web tutorial says this is not a problem if you have less than 3 batteries in your house "bank") My questions:

1) The dead separator under the hood is a Surepower 1315 which is bi-directional. With my situation, I am thinking all I need is a unidirectional replacement. I seriously doubt I'll ever be needing/wanting to start my engine from the house battery (although you never know ;)) What would you recommend? And if I do install a battery separator, should I add a DC-DC charger to avoid any potential problems with the lithium battery?

2) Behind the drivers seat is a Surepower 135001 LVD. I found the thread about bypassing or removing the LVD. I'm not sure what the LVD is doing for me at this point. Do you think I should be removing the unit or just leave well enough alone? (no harm, no foul)

I know I'm asking a lot, but any help you can give me would be most appreciated. When I was young, I must have been asleep when they taught "basic electricity". I'm pretty handy on most things, but electrical stuff makes my eyes glaze over.

Many thanks,
1997 Concourse SE Ford Triton 6.8L V-10
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