I have a 2003 Gem E4. It was unused for three months while we were out of town. When I returned, the car will not work. It was on a timer to charge the batteries weekly while we were away. When I plug in the car the Zivan fires up and the LED goes from red to yellow to green. If the the key is on there is no display in the panel and the car is dead. The headlights, wiper, blinkers all work, so the key switch is operating properly. The emergency brake alarm sounds if I lower the brake, so that sensor seems to be working. One other clue, if turn the master power switch off, leave it off for at least 30 seconds and then cycle it back on, then the center display momentarily flashes the miles (2521), then 0000, then goes blank.
You might have a failed battery or two. Check all the water levels and if ok then I would think the first thing to check is what the full battery voltage is. First test it powered off and then turn on the car, headlights and brakes and measure with that load on it. All 6 batteries should be at least 12.6V for a total of ~75V and you shouldn’t see that drop much at all with just the lights, brake lights and car turned on.
I charged the car overnight. All six batteries ranged from 12.6 to 12.75. I turned the headlights on and the voltage ranged fro 12.48 to 12.65.
While you don’t say you had the car turned on and the brakes on, the stock headlights pull about 4 amps and wouldn’t expect a fully charged battery to drop down to 12.4 volts from 12.6 on such a small load.
Did you check the battery fluid levels? Acid level should be just to the bottom of the inside filler tube. If you would ever see the tops of the plates exposed then the batteries are done. I would venture to guess that you have 1 or more bad batteries.
Do you still hear the loud relay clunk when you turn the car on and release the e-brake?
I double checked the water level and all six filler tubes in all six batteries were ok. I was not getting the loud chunk from the relay, just a small click. I let the cart sit, master power switch off, for 10 days, thinking if I has a bad battery the voltage would be down. Rechecked the voltage all 6 still 12.5 to 12.6. Turned master power switch on and plugged in the charger. Once the indicator light went green I turned the key, heard the loud chuck, and everything was fine. Not sure what really fixed it, but I suspect you were on the right path with a weak battery. Thanks for the input.