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Voltage for long term storage of LiFePo4

InMyImage

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We had an accident in our Fifth Wheel travel trailer and it is going to be at an RV repair facility for 2 weeks to a number of months based solely on parts availability. During it’s stay at the facility it will not be connected to any sort of shore power except brief periods when they need it for repairs and/or testing.

We have 2 DIY LiFePo4 12v batteries using 4 Lishen 272ah cells per battery.

Since they will not be connected to any sort of charger at all, I’m planning to disconnect the BMS but want advice on what voltage would be best for storing them for several months if necessary.

Note, the cells are brand new and only put in service 2 days ago which turned out to be great timing given we were stuck on the shoulder of a freeway in Southern California for 29 hours before we could transport it to the repair facility ?

Also, I’ve read through the following threads but they both had their batteries on chargers and were looking for long term charging profiles:



Thanks for any input, especially if @Will Prowse can give some advice.
 
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The BMS will draw so little power I'd leave it. Otherwise what happens if the repair shop turns the 12V power on to push out a slide or test a circuit?

Ideally you should store LFP at 30-50% charge. Assuming yours are at 90%+ I suspect they'll still be fine just sitting until you're ready. Even if it's a few months, your batteries will still be mostly charged when you get the trailer back
 
Since they will not be connected to any sort of charger at all, I’m planning to disconnect the BMS but want advice on what voltage would be best for storing them for several months if necessary.
I cannot tell if you plan to disconnect the loads by disconnecting the BMS. Your RV will likely have several light loads that over time can deplete a battery. If you can turn off the battery by the BMS that is a good option.
 
My thought was to disconnect the battery from the loads completely by removing the all negative and positive load cables completely but I hadn’t considered the event of them needing to pull slides in and out which will be done given some of the damage is to 3 of our slides.

I’ll pull the fuses for all unrelated circuits and the turn off the circuit breaker for our inverter.

With a 4s2p bank, 90% of 544ah should last them for their needs which will cause it to be used and gradually drained as they work on it.

Appreciate the input guys have a good one.
 
With a 4s2p bank, 90% of 544ah should last them for their needs which will cause it to be used and gradually drained as they work on it.
If you think they can check the voltage from time to time, it would be nice to be notified if the voltage ran below 12.5v or close so you could arrange to have it charged.
 
I realized that since the only charger available is the RV’s converter which has a feature that automatically initiates a de-sulfation stage for FLA’s that I shouldn’t leave the new battery packs connected so I going to swap them with the 2 FLA’s that were already in the coach since I have disposed of them yet.

Thanks again for everyone’s input.
 
Do you have a fuse to pull or circuit breaker to turn off between batteries and load
 
Do you have a fuse to pull or circuit breaker to turn off between batteries and load
Academic at this point, but we have both a battery disconnect and a resettable battery circuit breaker.

As mentioned earlier, I removed the litium batteries and reconnected the FLA batteries since I haven’t disposed them yet.
 
Like you say, academic at this point, but the batteries would have been fine sitting. Only issue is if unexpected larger loads drained them to low or if an unexpected charge was introduced to the system. You took the safer than sorrier route.
 
Like you say, academic at this point, but the batteries would have been fine sitting. Only issue is if unexpected larger loads drained them to low or if an unexpected charge was introduced to the system. You took the safer than sorrier route.
It’s likely to be another couple of weeks until we get the trailer back so the cells will have been sitting for roughly 3 months.

I completely broke down each battery pack so it will be interesting to see if they drained much while sitting idle
 
When I got my Eve cells they told me that 50 to 60% was the best for storing them for 6 months or more.
I hope this helps. :)
 
I completely broke down each battery pack so it will be interesting to see if they drained much while sitting idle
If by "completely broke down each battery pack" you mean the cells are separated, i recommend taking notes of the voltage of each cell. This may be a good indicator of their strength/capacity. Nonetheless, its a great opportunity to capture some good data with little effort.
 
If by "completely broke down each battery pack" you mean the cells are separated, i recommend taking notes of the voltage of each cell. This may be a good indicator of their strength/capacity. Nonetheless, its a great opportunity to capture some good data with little effort.
That is correct, all busbars and BMS’s have been removed and I have a screenshot of the BMS’s reported voltage for each cell to compare once I have put them back together again.

I’ll try to remember to update the thread again once I have the new values.
 
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