All lithium ion chargers stop charging once the battery is fully charged. I think your problem is related to the state-of-charge remaining at 100% continuously. Some lithium ion chemistries (like the lithium manganese oxide typically found in pre-2008 phones) lose capacity quickly if stored fully charged. You would need a charger which maintained the state-of-charge at a level lower than 100%, perhaps by not restarting charging until the SOC falls below 50%. Sean On Tue, Jul 7, 2015 at 12:17 PM, Art wrote: > Hi Everyone, > > I'm using some older driod cellphones (no cell service plan) as > extension phones in my house (Ooma.com) via wifi. Everything works > great, except the batteries are wearing out after 2 or 3 months when the > charger is left connected. > > If I don't leave them connected to the charger, the phone does not work > because the battery is always dead. If I leave them connected to a > charger, they wear out in a short period. > > Is there some kind of smart charger that will stop charging once the > battery is charged? > > Suggestions appreciated. > > Art > > > > > -- > 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 .