A full charge good battery is a must for this feeder.
I run a good EverReady none rechargeable. I was thinking of building a sub C pack that was 7.5 volts and rechargeable with nicad's. Not sure how much extra voltage you can put to these. The next step would be to put a 6volt relay in and run 12volts to the motor.
If I can get an extra bottom motor part I might just get a relay to try it.
We run mixed 2.5mm high fat sinking and 6mm floating in ours and the water and action is just high enough now to put a second shot of 2 sec on her.
Cheers Don.