The Super Brain 969 and 977 chargers can peak charge two packs at once. As Ken mentioned, the Hobbico R/C Multi-Charger can do four, but that is an "overnight" charger... only one of the outputs will go above 250mA for the charge current, and it doesn't peak detect. If you just want an overnight charger, that will work, but if you want a field charger, you'll want a higher current peak-detect charger (I field charge my packs at 400mA+, depending on the cell types).