[MetalMan]

The only problem I have really encountered with connecting any batteries in parallel is voltage differences between the packs. In the thread he mentions parallel charging of packs with <30% charge left in them. So if Pack A has 5% charge and B has 30% charge and they are connected in parallel, there will be a current flowing from B to A. The current level will be determined by the IR of the batteries and the resistance of the wiring/connectors. IMO it's not a good idea to connect packs of such charge discrepancy together in parallel due to rapid charging of Pack A (unless you have one of the newer 5C+ charge capable batteries...).