I agree. The cheap solar batteries in my shed have gone down to the point the BMS turned them off. So I added a second solar panel, then I added 3 more batteries in parallel. I just recently (with the help of my landscapers awesome shovel) moved the panels to a more optimal location and buried the DC cable to the shed. Now I never get lower than 70% SOC. I'm at 100% by 1pm on sunny days. It's a test off-grid system to power poe cams, smart bulbs, watch what wild animals try to eat my chickens etc. But really it is to see what location is best because I won't be cutting down trees I don't own, or don't want to.
Going strong since 2013. Some of these batteries now have bluetooth, I added a bluetooth module on mine. BMS protects the cells, keeps them balanced etc, just to add to that. I couldn't find the video but Will Prowse on youtube has a solar powered gate opener operating for years, battery exposed to the elements in las vegas, going strong after years. I don't think I will ever buy a lead acid based battery again. On Thu, Apr 10, 2025 at 1:13 AM Mark Tinka via NANOG <[email protected]> wrote: > > > On 4/9/25 14:27, Gary Sparkes wrote: > > Long term storage, of course, is different, but that's a much easier > solved problem, and design specs are often in the -30c to 25c range for > optimal capacity retention over long term storage. But operationally, > 25-50c is perfectly fine. Past ... above 5c, I think, you're looking at a > 10% capacity fluctuation in that 5c to 50c range. > > Yes, most LFP batteries will work even at 60°C, but that does not mean > you should do it if you want to get the most out of your investment. > > The biggest issue is battery aging, and keeping it within recommended > temperature values will ensure they last longer than if you don't. > > > > While true, heat is the enemy of lithium batteries of any type, deep > discharging is the second worst enemy (BMS prevents actual cell damaging > deep discharge, but you really should never go below 30% of rated capacity > if you can ever help it - this is the most stressful zone), then charging > too rapidly - too high rate of charge. > > The point of the BMS is to prevent you from operating your battery in > dangerous territory. > > 30% is not a reasonable floor to stop discharging a Li-Ion battery. All > you are doing there is limiting your available capacity. The recommended > floor to stick to is 20%. However, it is perfectly fine to go as low as > 10% without any appreciable loss of overall capacity. And in an > emergency, you can even go to 5% and still maintain good long term > capacity. > > This is where Li-Ion outshines LA by a mile. > > Limiting your capacity by not discharging to, at least, 20% SoC, is > quite pointless based on all the information we have so far, because > calendar aging is still going to get you either way. > > Mark. > _______________________________________________ > NANOG mailing list > > https://lists.nanog.org/archives/list/[email protected]/message/5UTUKUX4AWGUFY3LILDBEQGLTEBTOK64/ _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/[email protected]/message/6VWZ7P6WVWTIFZ64P6BJZLZWZY5PFVD7/
