Cleaning Rolls Standard 1/4-turn bayonet, R-Caps & Watermiser Battery Caps


You might notice a sticky dark gray residue on the inside of the standard 1/4-turn bayonet, R-Caps or Watermiser vent caps on Flooded battery cells. This buildup of dirt and dried electrolyte is fairly common and may clog the vent holes, preventing the release of hydrogen off-gas during charge. Inspect the caps and clean using a neutralizing baking soda and water solution as necessary.


1. Clean the caps by soaking in a solution of water and baking soda (100g per litre) in a bucket or small bowl. Let the vents sit overnight to neutralize and break down any electrolyte in the caps.

2. Flush the caps clean by forcing water through the vent holes. Water should drip freely. A trickle of water should flow from all vent holes, indicating the cap is clear of debris.

3. Allow the vents to dry completely. Once dried, shake recombination caps to make sure the condensing beads on the inside of the cap rattle slightly. If you do not hear the beads, let the cap dry for an additional 12 hours or repeat the process above.