Lifepo4 limits

[Diyguy]

First post, hello.
I bought some Ampere Time batteries 4-12v 300ah (48v system) have used them about a week and I do get pretty low by the morning 8-15% soc the manufacturer said no more than 4 in a system anyone have experience with this? Why would it matter? Is there a work around? I messed up tesla modules running them in a 48v setup due to them going out of balance and some cells bit the dust would like to avoid this in the future. Tyia

 

[HRTKD]

If you need a 48v battery, then build a 48v battery.

My opinion is that putting 12v LiFePO4 batteries in series is not an effective way to go. The first battery to reach the high voltage disconnect level is going to make it so that the other three batteries stop charging.

 

[Joe BoyKey]

I have the same situation, E-on says not to series, well for almost a year they are working flawlessly, 16 - 12v 50ah smart w/bluetooth - 4p4s - 51.2v 200ah, 1 battery out of 16 stops charging at 98%, all the rest are at 100%, I plan on fully charging batteries, finding that 1, disconnecting it and charging it the rest of the way up, then re hook and see, it's been this way a few months, I regularly check each battery via Bluetooth twice a week, also made sure to use buss bars and all cables the same length, Joe.

 

[houseofancients]

i can see why they told you to put no more than 4 in series for a 48v system.. more and you'll fry your inverter.
i would think it should be a problem to put more in parallel.
next to the added ah it would also bennefit your current batteries as the load on them will be half.
thing is though , if you parallel them, you need to add at least 4

 

[Joe BoyKey]

@houseofancients - good catch yes only 4 per series, but more series in parallel, those batteries seem awefully expensive, You can parallel in some different 48v Lifepo4 batteries like this, black boxes are batteries, 3 brands all Lifepo4 and counting, Joe.

 

[houseofancients]

@houseofancients - good catch yes only 4 per series, but more series in parallel, those batteries seem awefully expensive, You can parallel in some different 48v Lifepo4 batteries like this, black boxes are batteries, 3 brands all Lifepo4 and counting, Joe.
View attachment 56126

the only problem with that would be different internal resistances, causing an unbalanced battery, which will be a major head ache

 

[Joe BoyKey]

the only problem with that would be different internal resistances, causing an unbalanced battery, whichbin turn could be a major head ache

They all stay within a few % soc, EXCEPT the diy topbands always finish last @ 25-30amps for 15-20 minutes, hasn't been a problem and I'm working on it. Going to disassemble and clean homemade copper bars better and retop balance, 4 of the batteries from BH were 2.9v upon arrival and those 4 - cell 13 voltage is always higher and finishes up the lowest cell in the bank, ordered 4 more to replace them during rebuild, lot of work, will see.