LiFePO4 cells really, really don't like being "stored" at full charge.In fact, they don't like being stored at all, their ideal environment seems to be one of either charging or discharging. If they must be stored (ie, not being actively charged or discharged) then they are better off with a 25%-50% charge. As long as you are cycling the battery down once a week or so, then it'll probably be fine, but if you're rarely using it, keeping it topped off with a trickle charge when the sun's out then it's not likely to have a good long life. Further, they prefer pulse charging to trickle charging. If your application calls for a trickle charged rechargeable battery, you probably should look toward lead acid chemistry. I have yet to see a trickle charged lithium chemistry battery that was happy. I'd like to say you simply shouldn't do it outright, but I can't find evidence that it's a bad thing other than dim recollection of lithium ion charging literature, which doesn't apply very strongly here. -Adam On Wed, Nov 6, 2013 at 1:23 AM, Bob Blick wrote: > I have an MSP430 project here at home that runs off a single LiFePO4 > cell and I'd like to charge it off a solar panel. > > Capacity is not important to me, or efficiency, I just want the cell to > survive as many cycles as possible and not spend much effort with any > fancy charging methods. > > I was hoping to be able to float it at some safe voltage, if there is > one. My maximum charge current is less than 0.1C. > > My best guess is that somewhere below 3.4 volts is probably safe since > that's where a fully charged cell settles after a few days. > > Any LiFePO4 experience out there? > > Thanks! > > Bob > > PS My experience with LiFePO4 so far: I also have a Philips brand solar > light that I purchased a couple of years ago, it has a single LiFePO4 > cell and kills them after 100 days, so I know that you can't just > trickle into them and expect many cycles! > > -- > http://www.fastmail.fm - IMAP accessible web-mail > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .