I'm trying to expand my solar battery bank and I've found these 12.8V 560Ah LiFePO4 batteries. The total cost for four would be around $12.8k. If I set them up in a 4S4P configuration, that gives me about 114.68kWh. However, to maximize the lifespan of the batteries, I plan to keep them charged between 20-80%, which effectively reduces my usable capacity to 68.8kWh. Ideally, I'd love to have a 100kWh bank to run my system for five days or more if there's no solar production. Has anyone come across any LiFePO4 options that are rated at 820Ah or more?
3 Answers
Have you thought about going the DIY route? You can buy 280Ah 3.2V cells and build your own batteries. With a 4S4P setup, you'd get 12.8V and 1120Ah, which is almost double the capacity of what you're considering. If you want 48V, you could consider a 16S4P setup, which gets you 51.2V and a solid storage capacity.
Keep in mind that LFP batteries can handle being charged to higher states without degrading as much as other types. If you're cycling them with solar, they won't stay at 100% for long anyway.
If you're building a 48V system, I recommend sticking to 48V batteries. For the size you're talking about, it's probably the most efficient way to go.