Zapino Charger

Hi,
I'm back. I just switched on my new Zapino Charger and the switch is now stuck in the on position. Obviously I can unplug it, but I was wondering if this is a common problem.
Next, I can get a string charger to handle the 60 volts. Two questions: It just has positive and negative terminals, do I need to run a ground to the charger for the plug into the Zapino? Also, it has a 5 amp or 10 amp setting, can I run it at 10 amps and reduce the charge time?
Thanks,
zapmat