In April of 2013, I purchased parts to build my own 60 AH LiFePO4 battery. Back then it cost about $440 – about $100 more than a comparable battery can be purchased for today. That said, it has served me faithfully for those years, and seems to still be doing just fine.
I don’t use the 60 AH battery often, having discovered much smaller batteries better align with my operating style in the wild (why lug a 60AH battery around when you are using less than 3 amps/hour for a POTA activation?). The last time I charged the battery was October 28, 2018, or 994 days ago.
LiFePO4 batteries are coulometric efficient, with high efficiency of 99%. Because of cell balancing circuitry, which tends to bleed off some power, in reality, the amount of energy you put in will be a few percent higher that what was consumed.
Today, after recharging the battery, it took 1.08 AH. So in 994 days of sitting idle, it only lost 1.8% of its capacity. That’s about 1 mA of discharge per day. Talk about a low self-discharge rate!
This just confirms one of the many advantages of LiFePO4 batteries – you can charge them and leave them sitting for a LONG time and still expect them to be useful. A lead-acid battery left on a shelf for 3 years would be dead flat, and likely unable to be charged to any useful capacity.
60 AH 4-series LiFePO4 battery, first purchased in April of 2013.
