I see myself amassing a large amount of LiPo batteries. I would like build a charging bank to charge multiple LiPos at once. Can I even do that with the signal wire? All the batteries are 11.1 V but would be different MaH.
Not without potentially unbalancing the cells of each battery. You don't need to balance charge every time you charge, but I do just to be safe.
Multiple single chargers is the best solution if you have space. If you have a limited budget, you can get one charger at a time several times until you have sufficient charging capacity. If space is an issue (ie traveling to Nats) and you can afford the up-front cost, then a multi-charger is the preferred. I have a Venom Pro Quad (4 chargers in one unit) that takes up much less space than four separate chargers. I have also seen large banks of chargers for NiMH. Just eight dumb trickle-chargers and a really big power strip. Not that we see much NiMH in Fast Gun, but the chemistry is still popular in Big Gun.
I have a few of the Venom Pro Duo's and I just recently bought an ISDT K4 because the "Big Freaking Batterys" that run my largest boats take too long to charge on the Venoms. Needed something that could push 20+ amps per side.
