How long should I wait between charging and discharging for capacity checks?
*A: I actually had a guy that sounded like he knew what he was doing run me through hoops for days regarding low cycle numbers on his new packs. Finally he dropped the little missive, “I’ve been waiting 24 hours after the charge to start the cycle….” ARRRGH! Where do folks come up with this stuff? Here’s the deal.. ALL battery technologies have a self-discharge characteristic. NiMH self discharges at a higher rate than Nicad. Lithium has the lowest self-discharge rate…. but the point is, waiting a day (or an hour) to start a discharge after a charge will trend the capacity return downwards. Nominally, depending on cell type, age, impedance and temperature; a 10-15% capacity drop over 24 hours is not unusual. So.. whatever goofy procedure you use.. do it the same way each time, because if you change ANY parameter in a cycle test procedure you will effect a result in the returned capacity number. Time span between charge termination and discharge start impacts test results. Long lead
