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Old 11-30-19, 05:52 PM   #5
Robaroni
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Quote:
Originally Posted by philb View Post
Really impressive! Nice setup.

Your only using Flex 60's and 80's. No expensive BMS?

I have 24 GC2 6volt batteries on one system that die when the sun goes down. Most of them are 8 years old. $3800 for a traction demo battery. Maybe you could point me to a LIFEP04 retailer?

This post came at just the right time!
Thanks Rob!
I initially set up the system with a BMS system but after exhaustive testing
I found the best solution was to charge the bank to 3.4V (each cell 54.4V for the bank) max which, according to the data sheets on my batteries brings them up to almost 100% charge. I also spoke to the engineers at Tenergy who corroborated this.
I did carefully bring all the batteries into balance and I carefully checked all 576 batteries to make sure they were within 50mV of each other before putting them into the system.

Cheap Chinese BMS boards can't control batteries above a few hundred mV so it's best not to use them at all. The wires they use are too thin and the voltage drop across the wires makes it hard to regulate batteries well.

There's a YT guy named Will Prowse who's doing a lot of battery testing. My problem is that I simply don't have access to all the batteries so I can't give you hands on information.
From what I've seen the best LiFeP04's around is the Battleborn. I think it may have an internal BMS. Several people are using them with good results. If I had to go with a commercial battery this would be it.

https://battlebornbatteries.com/?gcl...SAAEgKTHfD_BwE
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