6 pack of 12 Volt 3/4" Round Hole Press Fit Watering System Battery Caps with Water Level Monitors

These things work great. I bought 2 flooded batteries for my man lift. The company overfilled them and I didn’t realize it until after the first recharge and battery acid was all over the garage floor. I went on line and found these. After the second recharge problem solved. No more spilled acid! You also get the benefit of an acid level gauge and fill port without removing the cap.

These fit great and are used in an RV to monitor the engine battery. Fill slowly to avoid overfilling.

I have a motorhome with three wet-cell, 12 volt, Interstate batteries wired in parallel for the coach. When I slide out the tray, it is easy examine the fluid level in each cell of the two front batteries, but the battery in the back is impossible to check without a mirror. Beyond that, any time I want to check them I have to pry up six multiple caps which drip acid, not to mention the need for protection for eyes and hands when doing so.

The original Interstate caps were press-in and these caps simply press in and fit perfectly. They seal tight and show no signs of wanting to come out on their own. They can be oriented so that the filler tube is very easy to access for filling the cells. The little black "ring" around the level indication tube is actually the water level indication mark that is user adjustable. On first installation simply be sure that the cells are at the correct fill level, snap in the cap, then move the
black o-ring to the bottom of the red mark on the visible float staff. When the red mark is below the ring, add water to that cell.

I recommend getting the water bottle they sell (not included with the caps) which comes with a hose that installs over the bottle's spout. Then just remove the fill plug on the battery's cap, push on the tube, invert the bottle and squeeze gently until the water lever is restored. The filling opening is well above the water level in the battery so there is no worry that acid can be pulled into the bottle. The rubber caps have a little plug protrusion inside to completely seal the filler opening.

At this point, the only thing that I would like to have seen added would be to include a cap for the fill bottle's spout so when done filling I could remove the tube from the bottle, place the tube back in the bottle (it ships in that location) and place the cap on the bottle to save the water for the next use. The rest of this system is so well designed that I find it odd they failed to see the value of a cap.

I spent about $60 for three sets plus the fill bottle. Sounds like a lot, but the cost of just one battery is much more, and keeping the cells at the proper level extends their life. A quick glance and just seconds later you know the cells are at their proper level. Anmd your hands are still clean!

The caps fit tightly, which is good. They seem to work as advertised. Very easy to see at a glance the level of electrolyte and if topping off is necessary.

Love it works great