The brand of battery does not matter. It's the power it provides. As long as it is within the specs and is good condition it is fine. Most used machines have aftermarket batteries in them.Still having problems with the T650- dealer says it's because it has a non-Bobcat battery (Napa). Was going to take it over for them to check, not it won't crank at all, even at 14 volts. Codes M6507, M1706, M2721, M0521