Radical RC has a great explanation of NiCad and NiMh batteries. https://www.radicalrc.com/shop/NIMH-...ew-Battery.php I have used the Walwart chargers that came with my radio to charge very large capacity 5 cell packs with no problems. The trick was to start with a fully discharged pack and using the formula I never had a pack that did not fully charge. Keep in mind that once fully charged you only need to replace what was taken out during a flying session.