Electric Golf Cart "running out of gas"

[RGrove]

The last couple of outings, my Cushman 36V has "run out of gas" very soon after pulling out of the cart barn. Last week, it made about two holes and seemed as though it was about to stop. I took it back to the cart barn and put it on the charger. The needle on the charger almost immediately dropped into the green, which is supposed to indicate a full charge. I left it on the charger anyway. I returned a couple of days later with a voltmeter and checked the battery back, read 35.2 volts. I did not have a chance to get it out and see how it was running then. Today I went back and checked the voltage, still at 35.2 volts. I could tell when pulling it out of the barn that it was probably not quite right but seemed better than last week. However, by the time I made it about halfway down Hole 1, I knew there was still a problem. I took it back down to the cart barn and checked the battery pack voltage again, now reading 33.4 volts. Probably driven no more than 1000 yards. Is nearly 2 volt drop normal?

Batteries were new this spring and have been taken care of. What tests can I run and what should I be looking for?