Battery Vent Cap Adapters

We manufacture battery vent cap adapters to convert most batteries to accept any bayonet style vent cap. Our invention solves the need for adapting any standard bayonet battery cap to fit virtually any deep cycle battery. This includes 4D, 8D, marine, solar, 12 volt, European style, and other batteries.

There are many reasons why you may need an adapter to replace the original battery vent cap. Some of them are listed below.

1) The original vent cap is broken or lost and you need a replacement.
2) You want to replace the original cap with a red, yellow, blue, orange, black, or white vent cap.
3) The original vent cap does not contain a flame arrestor and you want to replace it with one that does.
4) The original vent cap is too short which can cause the top of the battery to become wet with electrolyte. A taller vent cap helps to keep batteries dry.
5) The original vent cap allows the electrolyte to evaporate too quickly. Replacing it with a Water Miser cap reduces evaporation which means you don’t need to add water as often.
6) You want to replace the original vent cap with a water level indicator so you can check the electrolyte level without removing the vent cap.

Whether the original vent caps on your battery are the screw-in type (threaded) or the push-in style, we manufacture a battery vent cap adapter that adapts any bayonet style vent cap to most batteries. To order, select the picture of the adapter you need to enter our online store.

We make battery vent cap adapters to fit most batteries. This includes threaded and push-in style 4D and 8D batteries with a 3/4" diameter vent opening. Our 1050VCA adapter fits push-in style European batteries and select models of Douglas batteries. We also make screw-in adapters to fit threaded type batteries including those with metric threads. The items listed on this page are the adapters only. The battery vent cap is not included and must be purchased separately.

Battery Vent Adapter, Model #4D-8D-SIA

  • Fits 4D or 8D batteries with screw-in caps
  • Converts 3/4″ diameter threaded batteries to accept 1/4-turn bayonet caps
  • Screw-in style with rubber seal (included)
  • Made in the USA in our Ohio factory

You may order this threaded adapter in our online store.

Battery Vent Adapter, Model #4D-8D-PIA

  • Fits 4D or 8D batteries with push-in caps
  • Convert 3/4" diameter push-in style batteries to accept 1/4-turn bayonet caps
  • Push-in style (no seal is required)
  • Fits all batteries with 3/4" diameter vent holes
  • Made in the USA in our Ohio factory

Dress up your car's engine compartment! This battery vent adapter lets you replace the original plate style vents that cover all 3 holes with our yellow, red, blue, orange, black, or white battery caps. This vent adapter fits 3/4 inch diameter vent holes. Please measure your battery before ordering. You may order this push-in adapter in the online store.

Battery Vent Adapter, Model #M22X1.5

  • Converts M22x1.5 threaded batteries to accept 1/4-turn bayonet caps
  • Screw-in style with rubber o-ring seal (included)
  • Made in the USA in our Ohio factory

You may order this M22x1.5 adapter in the online store.

Battery Vent Cap Adapter, Model #M27X3-SIA

  • Converts M27x3 threaded hole to accept 1/4-turn bayonet caps
  • Screw-in style with rubber seal (included)
  • Made in the USA in our Ohio factory

You may order the M27x3 adapter in the online store.

Battery Vent Cap Adapter, Model #1050VCA

  • Fits European push-in style batteries
  • Fits some batteries manufactured by Douglas Battery Co.
  • Converts 1-3/8" diameter hole to accept 1/4-turn bayonet caps
  • Push-in style with rubber o-ring seal (included)
  • Made in the USA in our Ohio factory

You may order the 1050VCA adapter in the online store.