05' Gem Car loses Speed quickly

Hello all, I’m new to the forum here and a first time owner of a Gem Car.

I just bought a Gem Car EL and replaced the batteries today. Ran it up the road and could only go 18 mph. The batteries are fully charged. It takes about 5-10 min and eventually loses all speed and will not go. Indicator shows full batteries.

Any ideas? Motor? Controller?

I’m very new to these and I’m learning as I go.

Thanks for suggestions.

Check to see that the turf/road switch is in the road position. Make sure the brakes are not dragging. Check the voltages across each battery and compare them.