I’m guessing there are a couple issues, why some say that charger won’t/shouldn’t charge your packs.

It will take more than the 15 minute timer to charge 3600mah at 4 amps, more like an hour or so for a full charge. So you will need more than 1 crank. But ni-mh are particularly sensitive to over charging. Unlike a peak charger, a timer job won’t automatically shut down.

So you need to monitor the charge very carefully. Simplest but less reliable method is to keep checking the battery temp. They will warm slightly during charge, but at the end they will start getting warmer, then too hot to comfortably hold. Stop before they are too hot to hold, preferably before that, as they are starting to ramp up. Not easy to do.

More sophisticated, the way it was done in the day, is monitor the pack voltage. Notice the voltmeter taps? That’s what they are for. The voltage will rise slowly. Then stop and start to drop off. Soon as you see drop off, stop charging. That's what a Peak Detection charger does automatically.