for the last 15 years, In our farm we use 2 John Deere Gator TE, they are electric and came with Trojan lead acid batteries. It would take an hour a week to service them and when the batteries would no longer power them for a full day, we would just change them. We went thru 4 sets total and also changed corroded cables a couple of times. around 2016 our battery dealer proposed that we change to new LFP batteries and we converted one Gator to them and a year later the second one. We still run them to this day on those 6-7-year-old batteries. What we learned so far:
Don't power wash them, we had two failures because of batteries with an inch of water in them, I sent one to the dealer and he told me to forget about it and I opened the second one, drained the water, dried the cells and discovered that 90% cells still had 3.2V. The thin nickel strips had rotten away and the BMS still worked, I plan on fixing it for fun.
BMS rarely trip: for us it was because of an inexperienced driver not charging them at night. one cell would drop too low and the BMS would trip Low and strand the Gator. The old Lead acid Lester charger would not let a battery get above 13.4V so it never tripped High. Also I don't think we ever had a too hot event that tripped the BMS.
We did not know about not using the batteries in sub zero weather, and we dit it all the time. I don't know what it does to the battery but out of precaution we now recharge indoor above freezing and refrain from using the Gators below zero.
Because of the 2 failures, One of the Gator runs on only 4 x 12V batteries instead of 8. It is 50 kg lighter, drives better and has taught me the importance of balancing the batteries. When well balanced, the 4 x 12v gator runs longer than the 8 x 12V left as is.
Compared to lead-acid, LFP is 100 times better. We never service them, and all the problems we had came from the water event, BMS tripped low and vibration loosening the bolts. Whenever one doesn't work, I check the voltage, check the bolts and usually re-balance the batteries and it is good to go for at least a year.
I feel that LFP can last a very long time in a solar application: Well fused, in a climate control room, no vibration, dry environment with low charge and discharge rate, and a yearly inspection, It should last a very long time.
I wonder what Murphy's law type of failures such a battery would have?
Best,
Schopp
