sounds like you may have got a bad pack to start with & its cells are weak. trying to cycle back a pack thats going or is bad is often more trouble than its worth. it might come back but it very well may not .memory can develope but its often hard to do & from under charging cells , more often resulting from OVERCHARGING and damaging cells. which is harder to do with the wall wart. ive had packs last for years from regular use AND occasional cycling. there is no definitive answer because packs often differ for operational as well as design/ manufacturing reasons .inital charge should be 24 hours.