RE: Im building a 12S A123 from dewalt pack
I posted this on another thread but it applies here as well.
"If you are not a novice in electricity consider this.
I am able to charge packs beyond 4S with my FMA cellpro chargers. If you wire the node connectors, for a 6S as an example, as a 4S and 2S pack you can charge each "sub-pack" individually. So using a single charger you charge the 4S and then the 2S. The balancing ability of the charger allows you to do this.
Now here is a trick.... with two cellpro chargers you can charge both the 2S and the 4S at the same time! To do this you MUST have each charger on separate, isolated, 12VDC sources. Many AC/DC 12VDC power supplies have isolated outputs. If in doubt use two 12VCD gell cells or car batteries. The concern is that the negative side of the chargers can short circuit one of the packs if both chargers are connected to the same 12V source. For me this is an inexpensive way to charge larger packs accurately and easily."