[Assumption: you are talking about the used PbSO4 pack now being used for the PV system. My answer is more focused/applicable to the EV conversion driver with a PbSO4 pack.]
In my experience of changing several PbSO4 packs in my S-10 Blazer and the Escort I sold off, that changing out the entire pack is the best choice (if you can afford it, at the time I could). My EV goals were to have the most range available for long runs for testing and proving fast charging using multiple on-board chargers (I had 6 of them with their outputs in parallel. This was back before there was public L3 EVSE). http://brucedp.150m.com/blazer/blazer020504-001.jpg At the same time, the San Jose EAA Chapter had a member that was taking in packs that were for exchange, testing them, and only giving the actually dead/useless cores to the battery company for exchange. The used but still had life batteries were tested and marked for their capacity. So when a member had a battery go out, they could used the Chapter's battery exchange program to get another battery of similar performance and capacity of their existing pack. Since this exchange program was a labor of love (free to the member), it was a pretty good deal and good way to get the most out of a pack. But as far as I know, this program is not being performed elsewhere (some schmo has to have a backyard full of partially to dead wet-cells, and a rig in the garage to charge-discharge-test them ... can-you-hear-her-complaining?). So, since it is likely you do not have access to a similar free used battery program, then my second choice would be to buy a cheap new battery of about the capacity that is left in the batteries you have. But, over all you are paying now and again when you replace the pack, vs paying once if you just replace entire new pack now. {brucedp.150m.com} ... http://dictionary.reference.com/browse/schmo - On Tue, Nov 5, 2013, at 05:37 AM, Barry 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. - -- http://www.fastmail.fm - Choose from over 50 domains or use your own _______________________________________________ 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)
