I need to charge 2 12v batteries that are wired in series for a 24v cell

[cutlass1972]

I have a big ups system that I picked up that has a bank of 12 volt gel cell batteries that are in a series parallel configuration that add up to 24V. I have a 12v 30 watt solar cell. My question is, is there a way to charge the 2 banks of 12v cells in parallel at 12v using my solar cell while they are wired in series?

I have thought I could possibly create a circuit with latching relays that will toggle from one battery bank to the other every couple of minutes so each bank is being charged independently, but this seems like a lossy inefficient way of doing things. I cannot think of a way to isolate each bank of batteries to charge them at 12v.

[wpowokal]

You could adapt this circuit....

http://www.talkingelectronics.com/te_interactive_index.html

allan down under

[Flux]

Time sharing would work after a fashion but you may have trouble keeping batteries in step. It's a messy way but possible.

The other way is to use a boost converter but you would need to experiment. There may be commercial boost controllers but I haven't met one.

Probably cheaper to buy another panel than waste time building some doubtful contraption.

Flux