I generally fly out four batteries a day. I used to charge my batteries one at a time and this usually took around 3 hours to charge four of them. After I learned about parallel charging my charging time was reduced to 45 minutes!
If you need to charge more than 6 batteries at a time, you can daisy chain two ParaBoards together but be mindful not exceed the 35 amp max charge rating or you may blow the fuse.
The ParaBoards are constructed from 1.5mm fiberglass pc boards with 2oz copper traces. The main bus bar has been built up with solder to increase it's current handling, resulting in a 25amp continuous current output and a maximum current output of 35 amps for a period of 10 to 15 minutes. The injection molded cases are made from a special, fire resistant ABS plastic.
If you have never parallel charged before, we recommend doing a google search on the subject so you can learn the do's and dont's of parallel charging. Your batteries can burst into flames if you do not do this properly.