Battery Vent Cap Adapters

We manufacture vent cap adapters to convert any threaded or press-in type batteries to accept any bayonet style vent cap. This includes 4D, 8D, marine, solar, 12 volt, European style, and other batteries.

There are many situations where you may need an adapter to replace the original battery vent cap. The reasons may include the following:

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 causes the top of the battery to become wet when the electrolyte splashes or overflows. A taller vent cap helps to keep batteries dry.
5) The original vent cap allows the electrolyte to evaporate too quickly, and you want to replace it with a Water Miser cap so that you don’t need to add water as often.
6) You want to check the electrolyte level without removing the vent cap, so you want to replace it with a level indicator.

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 will retrofit any bayonet style vent cap to most batteries. To order, you may click on the picture of any adapter below to enter our online store.

We have battery vent adapters to fit many batteries, including push-in style 4D and 8D batteries that have a 3/4" diameter vent opening. Our 1050VCA adapter is for push-in style European batteries and select models of Douglas batteries that have the same type of vent well. 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 cap itself is not included and must be purchased separately. Our entire line of battery vent caps may be viewed here.

Battery Vent Adapter #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)

You may view this threaded adapter in the online store here.

Battery Vent Adapter #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 required)
  • Fits All Batteries with 3/4 Inch Diameter Vent Holes

Dress up your car's engine compartment! This battery vent adapter lets you replace the original plate style vents that cover all three 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 view this push-in adapter in the online store here .

Battery Vent Adapter #M22X1.5

  • Converts M22x1.5 Threaded Batteries to Accept 1/4-turn Bayonet Caps
  • Screw-in Style with Rubber O-ring Seal (Included)

You may view the M22x1.5 adapter in the online store here .

Battery Vent Cap Adapter #M27X3-SIA

  • Converts M27x3 Threaded Hole to Accept 1/4-turn Bayonet Caps
  • Screw-in Style with Rubber Seal (Included)

You may view the M27x3 adapter in the online store here.

Battery Vent Cap Adapter #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)

You may view the 1050VCA adapter in the online store here.