I have several 3800 and 4200 packs that continue to build up resistance with just about every charge. These packs are about a year old, and probably have a 100+ cycles on them. They sat most of the summer outdoor season as I ran LiPo at our club races, but I put a little charge (300-500 seconds) in them and cycled them every 2-3 weeks.
The problem is that they have insane amounts of resistance in them and it keeps growing. I have a Trinity DPD that I usually use for the discharge cycle, but still no help. About a month ago, a couple packs were worthless, but 3-4 had resistance in the 30-40 milli-ohm range on the DPD. Over the last month or so, all but one of these packs has grown to 75-100 milli-ohms of resistance.
Does anyone know of a good way reduce the resistance out of these packs? I've tried 4 phase charges on my CheckPoint charger, 1/10 C charge rates with 1 C discharges, etc., but have had absolutely no luck. Or do you all think these packs are just spent? With a 6.5 in my B44, it spools up like a stock motor [
]. The voltage and runtime on the packs are still pretty good as several of them have an average pack voltage of 7.15-7.25 on a DPD discharge.
Anyway, if anyone has an idea to salvage the packs and save me some money, I'd appreciate it. I'm wanting to avoid buying any more NiMh cells if possible as more of the places I race allow LiPo all the time, but I still need to have a few NiMh cells that are at least good enough for mod classes at the tracks that don't. I have a used Spintec battery manager on the way, do you think it will do anything?