Svenska ElektronikForumet

First of all find out the maximum current your batteries can be charged with: it helps if you post the type and size or the modelnumber here.

Then figure how fast you want/need to charge the batteries. Faster means more expensive hardware.

When you know that, you can start designing a charger that handles the current needed.

Since you are using fuel cells you probably care some about efficiency. If that is the case i strongly advice you not to max the cells. Somewhere around 30% of max output you will have what most considers to be the highest current you should be able to draw with acceptable loss. When you max the cell you will probably use about 5-10 times as much fuel for the same energy.

So with the figures given i would guess that just limiting to the recomended charge voltage could very well be sufficient, 28,8V, if you charge them in series.