Yeah, 60v is more around 70v, or higher fully charged in the lifepo4 world.
Sorry bluefang, but i don't agree. This controller most likely has 63v caps and FETs that aren't capable of more than 63v either. Open it up and see what the voltage rating on the big caps is. Then go find out what FETs you have, look them up online and see what the voltage rating for those is as well.
Good way to blow a controller is to run it above it's rating.