The submersible I'm working on at work carries 6 lithium batteries, connected in parallel. Each is roughly 24V. They are in a sealed hull, with an egress port which can carry wires to the outside world. I'd like to recharge the batteries in situ - that is, without having to unseal the unit, remove the batteries, recharge, seal the unit back up, etc. So the ideal would be to just plug in a recharger and have it recharge the batteries through the wires coming from the port.
The problem is that the batteries must be charged independantly. So that parallel connection of all batteries must first be broken, each battery charged independantly, and then the parallel connection restored. If that makes sense. In short, I'd like to have a circuit which would cycle through all the batteries, charge each, then restore the original configuration.
Now I may be coming at this from the wrong angle. Perhaps it's a simple thing to charge the batteries when they're connected together, but I believe we've been advised this is not a good thing to do.
Another issue might be venting of gases; I haven't checked, yet, to see if lithium polymer batteries are safe to recharge in a sealed environment.
But in any case I thought I'd throw this problem up and see if anyone has some lateral suggestions, perhaps something as simple as whacking on a diode in the appropriate place, and a dab of glue...
Cheers
A