[–] rcxdude 3 days ago
[–] mnw21cam 2 days ago
A lead-acid battery mainly ages by cycle count. If you keep a decent quality battery charged up, and don't regularly discharge it too much, then there are claims they will last ten years. If you discharge them excessively each day, then you'll kill them really quickly.
A LiFePO4 battery has a quoted cycle count. But really what matters is simply elapsed time - the battery will last about ten years if it isn't abused, and you'll be hard-pressed to actually do that many cycles in that ten years. It ages mainly by elapsed time, not cycle count.
I used to argue that for an off-grid solar solution, you should get lead-acid batteries with capacity so that you are normally never discharging below 70%, and that this was still cheaper than getting LiFePO4 batteries with smaller capacity that you would discharge down to 20% each night. The lead-acid would then give you a larger reserve capacity for those instances where the weather is foul for a bit longer than normal and you don't get meaningful charging.
However, since then LiFePO4 batteries have continued to decrease in price, there are new Sodium batteries available now, and I haven't done the calculations again - the best option may have switched over, or it may be so close that it doesn't really matter which one you choose.
[–] foobarian 2 days ago
[–] ElevenLathe 3 days ago
[–] rcxdude 3 days ago
[–] adgjlsfhk1 3 days ago
[–] Schiendelman 3 days ago
[–] sieve 3 days ago
I have a 5 kWp solar plant that produces ~25kWh per day, but it is grid-tied. I considered a hybrid setup with LFP battery back up, but decided to separate the two systems to avoid a single point of failure.
[–] literalAardvark 3 days ago
LiFePo4 however is excellent and reasonably low cost these days
LiFePO4 is probably the chemistry best suited to it ATM. Lasts a long time, more stable, pretty cheap, and just a bit less energy density than other lithium ion options. Sodium-ion is looking promising but only just entering the market AFAIK.