LEDt light bar slowed my cart down

[tphogg@aol.com]

2013 Precedent, controller on high-speed setting, premium light kit, 3 mo. old batteries. I put a 24" LED light bar on the front and tied into main head lights, if I stop for a second with the lights on and take off again the cart will go in a slow speed? I stop ,turn lights off , take off again it runs at high-speed again, turn the lights back on and everything is ok? Only happens if I stop for a minute and take off again?
I have the lights wired to 16 volts !