I had my Seagull die for no reason early this year. I had to ride about 1 mile home without power. It ain't easy! I tested the battery and it was totally dead and would not charge. No reading at all on meter. They sent me a new battery as well as a new controller, no problem. I did have to take a photo of the old battery with the volt meter hooked up and show the 0 reading. I think they skimp on batteries, and they are a known issue. Get a multimeter for $5.00 and test the voltage on that battery. If it reads less than what it should on full charge or if it reads nothing, then that's your problem. Also, check your battery fuse. If the fuse is good, (use the multimeter to check it too) and the battery is still dead, then it's the battery, and they will ship you a new one. You can toss out the old one. Also open the controller box and make sure all the wires are connected. Don't try super steep hills on hot days! Overheat the battery and it's toast. I never ride in temps over 90.