Single Point Battery Watering System

I just purchased a 2008 GEM Car E2. It came with Deka EV31 Flooded
Cell Batteries that have screw on fill caps. This means 36 fill caps
to be unscrewed once a month to check water levels. In addition some
of the caps are covered by battery cables so that the cable have to be
removed to check water level.

I found that there are battering systems available for golf carts that
use fill caps connected to plastic tubing that connects to a pump to
fill all cells simultanionsly. The problem is none of these fill cap
valves fit the Deka EV31. Apparently a german company Rover & Rover
makes a fill cap product brand name AquaPro that will work. They are
sending me a test fill cap valve to try out.

Has anyone had experience with the single point battery watering
systems? Has anyone had experience with the EV31 battery? Any insights
into this method for filling GEM Car Batteries would be greatly


I believe I found the soluton to the problem of fitting a single point water system to the Deka EV31 batteries that came with my 2008 E2 GEM Car.

The problem was that the standard single point watering systems are not compatable with the Deka batteries. The solution was a German made valve, brand name Aqua Pro that makes a valve for generic 12V batteries that use an o-ring for the seal vice the normal twist lock. They make the valves with several size floats to accomadate various brand batteries. After extensive research by Tom of RV Power Supply, he found that using this valve with the #166 float work work in the Deca Batteries.

I purchased a set a month ago for trial. I installed them on the rear two batteries. Installation was easy. Filling the batteries is a breeze. I was worried about leakage of battery acid but to date I have observed none. I purchased the valves for the additional four batteries an installed them.

I can now fill the batteries in about 5 minutes vice the two hours that it took before. The cells are all filled to the same level.

I appreciate the extensive research that Tom of RV Power Supply did to come up with a solution to the single point battery watering system for the Deka EV31 battery in my 2008 GEM car. Contact information for him can be found at