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As another commenter pointed out, Lead-Acid batteries are terrible for this. They are fine for backup power supplies that you don't expect to actually use more

As another commenter pointed out, Lead-Acid batteries are terrible for this. They are fine for backup power supplies that you don't expect to actually use more than a couple of times a year, but discharging them too much will completely kill them, and even if you keep a margin and discharge them to only 30%, the number of cycles is quite limited (1500 to 3000 cycles quoted in [1] seems a bit optimistic, probably depends on the specific battery). Lithium-based batteries such as LFP are becoming very affordable [2] and can handle much more cycles. They can also handle more current variation and are more efficient. [1] https://offgridtech.org/tech-updates-online/2021/lithium-iron-phosphate-batteries-pros-and-cons/ https://offgridtech.org/tech-updates-online/2021/lithium-iro... [2] https://news.ycombinator.com/item?id=28943741 https://news.ycombinator.com/item?id=28943741

41b696ef1113 5y ago
Technology Connections[0] did an episode where he talked through some of the science behind why lead acid batteries work poorly for the task. He used a marine deep cycle battery as a compromise solution. [0] https://www.youtube.com/watch?v=1q4dUt1yK0g https://www.youtube.com/watch?v=1q4dUt1yK0g
makomk 5y ago
The problem with LFP batteries is that they really need to be kept resonably close to room temperature in order to be efficient and safe to charge. This is fine if you're using them for some kind of off-grid home that needs to be heated anyway or for intermittent high-power applications like cars that can cope with the energy required for heating and cooling them, but it won't really work in this setup.
- MayeulC 5y ago
  Thanks for pointing this out, I didn't have it in mind. You probably need some insulation, and some sort of heating, although the computing device could probably provide the heat. Handling summer/winter cycles without human intervention might be a bit complex, but intervening twice a year doesn't seem too much hassle. > it won't really work in this setup. I don't recall reading that it was placed outdoors.

41b696ef1113 5y ago

Technology Connections[0] did an episode where he talked through some of the science behind why lead acid batteries work poorly for the task. He used a marine deep cycle battery as a compromise solution. [0] https://www.youtube.com/watch?v=1q4dUt1yK0g https://www.youtube.com/watch?v=1q4dUt1yK0g

makomk 5y ago

The problem with LFP batteries is that they really need to be kept resonably close to room temperature in order to be efficient and safe to charge. This is fine if you're using them for some kind of off-grid home that needs to be heated anyway or for intermittent high-power applications like cars that can cope with the energy required for heating and cooling them, but it won't really work in this setup.

MayeulC 5y ago
Thanks for pointing this out, I didn't have it in mind. You probably need some insulation, and some sort of heating, although the computing device could probably provide the heat. Handling summer/winter cycles without human intervention might be a bit complex, but intervening twice a year doesn't seem too much hassle. > it won't really work in this setup. I don't recall reading that it was placed outdoors.