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Van Conversion 300ah LiFePO4 Setup Recommendations

ColtClimbs

New Member
Joined
May 9, 2023
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9
Location
Washington
Hello, my girlfriend and I just bought a van that is mostly converted. It has a lot of high quality gear such as victron 3000w inverter, mppt solar controller, 2 dc-dc chargers, stove top, fridge. The only issue we have run into is the LiFePO4 batteries are damaged. The van was sitting for 2 years in storage and now the existing GBS 300ah (from starlight solar) batteries will not hold a full charge.

Rather than risking trying to salvage useful cells, I plan to get a drop-in replacement. My budget is around $1000-$1200 and my current considerations are the Chins 300ah w/ blutooth and low temp heating ($1139) or LiTime 300ah ($1099). Low temp cutoff and SOC are both important to have, but I figure I can also get the victron smart sense and smart shunt on the LiTime to solve these. I currently feel that LiTime has a better build quality and higher quality cells (Chins says nowhere about grade A cells), so I am more inclined to go that direction. That would put my a little over budget, but might be worth it for higher quality.

Please let me know if you have thoughts on my situation, preferences between these options, or thoughts on different batteries/setup.

Thank you!
 
The van was sitting for 2 years in storage and now the existing GBS 300ah (from starlight solar) batteries will not hold a full charge.
Just out of curiosity, how do you know it won't hold a full charge? Have you done a capacity test? Are you sure its being fully charged before your determination?
 
After fully charging with shire power through the inverter, the voltage immediately starts dropping and settles around 9.85 volts. Im not a battery expert by any means and I could be doing something wrong, but that tells me there is something wrong with the cells. The BMS will disconnect if I try to run any appliances.
 
Is your battery(s) made from these cells?

After fully charging with shire power through the inverter,
What "inverter" are you using to charge your battery(s)?

What BMS?

Happen to have a pic of your battery?
 
That is the correct brand, however they are 3.2v 100ah and 3 of those in parallel to get to 300ah. The BMS is from starlight solar and it has a RCA cable that goes to a screen and a few contractors to disconnect for high/low voltage. Here are a few pictures.
 

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The BMS is from starlight solar and it has a RCA cable that goes to a screen and a few contractors to disconnect for high/low voltage.
I am not sure that is really a BMS, it looks like a battery monitor (no safety features that a BMS provides). I believe this because it does not have a way to cut the battery negative path from what i can see.

Also, it looks like the 3 parallel batteries are wired incorrectly, with the positive an negative loads/charge from the top most battery.

I would not be surprised if this battery could be resurrected given the problems with the installation.

If it were me, i would disassemble the batteries into the 12 cells and try to evaluate each cell. If each cell looked reasonable, would top balance them, get a BMS for each battery (or assemble them 3P4S with a BMS) and install the battery(s) correctly.

Worst case, I would expect that at lease 8 cells would still be good enough to make a 200Ah battery.

Do you know what causes the Victrom MP to stop charging? Does it rely on information from the battery monitor or does is only use overall battery voltage to terminate charge? If you post your MP's battery charging profile, that would be easy to inspect/diagnose.
 
The BMS is from starlight solar and it has a RCA cable that goes to a screen and a few contractors to disconnect for high/low voltage.
I am not seeing any contactors. Can you provide a pic? With 3 batteries, there should be 3 of these at the battery, before connecting in parallel with other batteries. And these are normally on the negative side, which you show pretty clearly in the pics.
 
OK, so here is a link to starlight solar for reference. Their website kinda sucks. They state that it is an "energy management system" rather than bms, but essentially the same thing.

Attached is a picture of a 12v 100ah battery pack (which has a couple hydraulic press aluminum bars to fit the 4 cells together).

The disconnects are from gigavac and are ok the top of the setup. I believe this was set up by an electrician so I assume it is correct and does appear correct to me with my current (beginner) knowledge. I realized I have a wiring diagram, so I've added that as well.

I plugged in the shore power, turned on charging only mode on the MP, turned on the EMS and here are the readings. After about 1 minute, the EMS turned off and it stopped charging. The battery has not gone into absorption mode and slowly starts to drop voltage. There was a warning indicator stating "battery voltage ripple" as well. I'm not sire what causes the charging to stop.
 

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They state that it is an "energy management system" rather than bms, but essentially the same thing.
This does seem to be more or less the same thing as a BMS. But the one you have only looks capable of monitoring one 12V battery (five voltage sense leads, which is enough to monitor four cells), and you have three batteries in parallel. Your EMS may only be protecting four of the 12 cells. If the 12 cells were set up 3P4S, that might work fine, but that doesn't appear to be the case.
After about 1 minute, the EMS turned off and it stopped charging
I'm guessing it recorded an overvoltage on a single cell, but it's hard to say. Does the EMS have a display? What does it say the voltages are for the cells? Does it throw a warning or error message when it disconnects?
I plugged in the shore power, turned on charging only mode on the MP, turned on the EMS and here are the readings. After about 1 minute, the EMS turned off and it stopped charging. The battery has not gone into absorption mode and slowly starts to drop voltage.
88 Amps for 1 minute is about 1.5Ah, so the battery isn't accepting anything. You might try charging a little slower, like 10 Amps to give yourself a chance to see what's going on before it turns off. But if the EMS doesn't tell you anything about the cell, it may just be a way to actually do damage to the cells.
Since you're thinking about replacements anyway, I would be very much inclined to take that box apart and see how everything is actually connected in there. @MisterSandals is right, there's a decent chance there are enough good cells left to salvage something.
There was a warning indicator stating "battery voltage ripple" as well. I'm not sire what causes the charging to stop.
This can be caused by poor connections. Your setup has a LOT of connections and there's likely considerable resistance. If you do rebuild the battery, invest in some proper cable lugs and a tool to crimp them.
 
Thank you for the input as well LakeHouse. I tried lowering the charging to 10a and it cutting off in about the same amount of time (I took a screenshot as well in case I did it wrong). I'll try to take the setup apart to get a better idea of what's going on at the cell level. I've been a little apprehensive as there is a lot going on and I want to be able to safely disconnect things, but will be kind of guessing on how to do that.

I believe the setup is 3p4s. Here's a drawing of what I believe the setup to be. Hopefully that makes sense.
 

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You decreased your AC in to 10 Amps, but that shows your battery charging 66.7 Amps:
1683667497005.png
In the nomenclature normally used on this site, the battery setup you've drawn would be specified 4S3P. As in, you've put four cells in series, and then connect 3 such 'sets' of cells in parallel. In that arrangement, your EMS can't monitor or balance any more than one of the sets of series cells.
 
I believe the setup is 3p4s. Here's a drawing of what I believe the setup to be. Hopefully that makes sense.
The battery is setup as 4S3P which means you have 3 batteries which each NEED a BMS.
And, the way it is wired, the top battery (front in your pic in post 10) gets the most charge current, the back the least. Similarly, the frontmost provides most of the load. You may only be using the equivalent of 2 batteries (8 cells) as wired.

One of the leads should be off the bottom (back in pic) battery for a balanced battery bank.

Who knows how this has been effected by deep discharge. Certainly charging with lower current AND balanced wiring will help a LOT.
 
I see what you're saying now about the wiring. From what I could find from the manual, I believe each cell has a board on it and the EMS can handle different configurations. The numbers are all over the place when I turn on the screen, but it is recognizing 12 cells. I'm going to try to wire up the "page" momentary switch to see if I can get a reading for the individual cell voltage and temp.
 

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I think we're making progress. I was able to use a wire to toggle to the individual cell page. It appears that cell 4, 7, and 10 are out of balance and likely damaged. I'll plan on disassembling the packs, see how the cells settle once disconnected, take out any bad cells, top balance, and see if I can re-assebmle for 200ah with the correct wiring.
 

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Try charging the under volt cells VERY slowly, like 1-5A until they get up over 3V.

It looks like the EMS is NOT for LiFePO4 cells since it mentions 3.8V max voltage. LiFePO4 should have a max of 3.65V (2.5V min) and a slightly tighter daily operating range.

Is there a way to set the battery type to LiFePO4 or to set the limits to appropriate values?

The battery wiring looks balanced. That will make a significant difference.
 
Try charging the under volt cells VERY slowly, like 1-5A until they get up over 3V.

It looks like the EMS is NOT for LiFePO4 cells since it mentions 3.8V max voltage. LiFePO4 should have a max of 3.65V (2.5V min) and a slightly tighter daily operating range.

Is there a way to set the battery type to LiFePO4 or to set the limits to appropriate values?

The battery wiring looks balanced. That will make a significant difference.
I will give that a try. The EMS is definitely for the cells in the system. These were both purchased through Elite Power Systems from AZ, the main US distributor for GBS batteries. I'm pretty sure these cells have Manganese in them as well so they are technically LiFeMnPO4 cells. Not sure if the slightly different chemistry accounts for the different high voltage cutoff values.

I'll read through the manual again to see if there are any different settings, but I don't believe that is the case.
 
I'm pretty sure these cells have Manganese in them as well so they are technically LiFeMnPO4 cells. Not sure if the slightly different chemistry accounts for the different high voltage cutoff values.
Ah, ok, i did not know that was the chemistry.

Based on this link from a quick search, it looks like you are good on the limits. If adjustable, my personal preference is to stay a tenth or 2 from the theoretical limits with cutoff and slightly more conservative with charge and discharge settings.


Good luck! I would not be overly surprised if you cannot resurrect all 12 cells. There are things you can do in arranging the batteries to better handle slightly mismatched cells (cells with different capacities in particular).

Label your cells (i like letters A, B, C... because cell position in a battery is a number with cell 1 being on the negative battery end) and take good notes. This is crucial going forward.
 
they are technically LiFeMnPO4 cells. Not sure if the slightly different chemistry accounts for the different high voltage cutoff values.
No, those GBS have very similar charge/discharge curve than most LFP cells. The 3.8V cutoff is simply a bit to high.
You can certainly save this battery, your money and battery ressources.
Good luck.
 
To me your best solution is to test all cells in capacity and match 4 groups of 3 cells connect together to only have ''4 cells'' of 300Ah (or XXXAh after test).
This could give you a low cost battery good for many more years.
 
Thank you all for the input. The 3.8 figure was just listed in the manual for the EMS. I will see if I can set different limits that are lower. I think I need to order a dc power supply from Amazon to slowly charge the cells individually, as I only bought a Noco 1 because it had a force feature to wake the batteries up.
 
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