backchannel: this week in battery mistakes
not a deep cycle
> I put a single [1400Ah (700 useable) wet cell](https://www.napaonline.com/en/p/NBP8276) in my travel trailer at 170 pounds. No solar yet
Uh, no. OP bought a marine battery with 1400 CCA. Not a deep cycle, as s/he will find out within a year.
killing me softly
> 655ah of batteries! ... I got 960w of solar on the roof to charge them too!
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it’s a mismatched bank of one excellent AGM (Lifeline) and two other SLAs, presumably AGM. Good luck with that, and my condolences to that nice Lifeline (excellent batteries, this example is ~$650)
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AGM requires C/5 charging current at a minimum. Example: lifeline says they require a minimum of .2C (C/5) charging or “the cycle life of the battery may be negatively affected”. Ie, they will die early.
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The solar will provide 70A of charging on a good day (960w - at least 15% heat derating and DC-DC losses = 816w, 816w / 12v = 68A. .2C charging would be 131A for a 655Ah bank. Kids in grade school can tell you that 70 is much less than 131. About half.
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