Expected lifespan for a golf cart type battery in solar use is 5 to 8 years. With the first few years being much heavier use in an EV, I would probably trend more towards the 5 to 6 year mark. So.... there's probably not much life left in even the ones that haven't failed. I would probably replace the whole pack, and go with something with a higher AH capacity, so you can reduce the number of parallel strings (I imagine that you are running multiple parallel strings when you reconfigured from EV to house voltage). My experience in adding new batteries in parrallel to old ones is that the new ones last about as long as the old ones -- i.e., if there is two years of life left in the old ones, the new ones also only last two years, even if normally they'd last 6 years. So, you would be sacrificing a lot of life by adding new ones to the old ones. What was the failure mode of the ones that failed? If they failed with shorted cells, it indicates that shedding plates are building up in the bottoms, and eventually shorting out the plates. That is not a good sign, and more will probably follow quickly. I've had banks that started failing shorted, and I shuffled them around to keep it working, and every three or four months, I had more shorted cells to work around, for about a year and a half till I replaced them all. If it's just lowered AH capacity, then it's more like a slow failure, rather than suddenly becoming unuseable.
Z On Tue, Nov 5, 2013 at 6:37 AM, Barry <[email protected]> wrote: > Slightly OT but given the group's experience with batteries figured I > would ask here. > > About two and a half years ago I replaced my original flooded lead acid > battery pack (US2200XC) with lithium cells and re-tasked my flooded lead > acid batteries to solar backup for my house. Now almost five years out > four of the twenty four original batteries in the house backup have failed. > I reconfigured the pack and can live with the reduced capacity for a > while. But I would like to add the capacity back. > > Options: > 1. Replace the four bad batteries with four new batteries of the same > type and rated capacity as the original. > 2. Replace the four bad batteries with four new batteries of capacity > roughly 60% of the original (trying to match what I think the current > capacity of the original batteries). > 3. Spend $2-$5K on a new pack. > > Thoughts? > > Thanks in advance, > Barry Oppenheim > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20131105/088d94ab/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
