Hmm, problems when charging?`I just dis-solder and charge.
You need bent batterybars on the batterywirepoles though so you have something to solder on and for the chargers alligator clips.
A "on-off-able" fast-heating and WARM soldering iron is the best.
*edit* whole reply got weird..
JMI Motorsport / Red Bull Racing
HB Cyclone TC - Schumacher CAT SX & Cougar SV
Advanced Electronics - Autopartner.se - Savöx - NorthTQ