Battery Vent Cap FAQ

Which vent cap will fit my “brand X” battery?
Unfortunately, we have no way to cross-reference our vent caps with specific battery manufacturers, because there are so many different styles, sizes, and configurations of batteries.  You would have to look at your cap and then go on our website to view the various types of caps we manufacture and determine if they will work. All of our product dimensions and specs are available on our website in the PDF drawings. Please measure your existing vent cap, then compare your dimensions to the measurements shown on our PDF drawings to determine if it will fit.

Do you make replacement caps for car batteries?
Not specifically. However, if your battery has a ¾” diameter push-in vent cap, you could pair our #4D-8D-PIA adapter with either our #1070 or #1050 vent cap. You would need to make sure there is enough clearance before ordering. The adapter/cap assembly measures 1-3/8″ inch diameter x 1-1/8” high. That size may be larger than the original battery caps, so check both the side clearance and the top clearance when you close the car hood.

I do not see a vent cap that will fit my battery. Do you manufacture an adapter for battery vent caps?
Yes, we make several adapters. They will adapt any standard 1/4-turn bayonet battery cap to either a threaded type or a push-in type battery orifice.

Which of your battery caps are the most popular?
Our basic vent caps are models #1050 and #1070. Some battery manufacturers use the #1050 on their high-production batteries due to their low cost. It does not contain a flame arrestor. The #1070 safety vent cap has a similar size and shape, but it has the advantage of containing a flame arrestor.

Another popular model is our #2000 flip-top Water Miser vent cap. The flip-top cap allows you to check the electrolyte level and add water without removing the cap from the battery. Water Miser technology reduces evaporation, saving time and maintenance costs. It also contains a flame arrestor which has the added benefit of reducing harmful battery fumes in work areas. It is available in 3 different heights, and the differences between part numbers are explained below.
#2000 This is the shortest (0.63″) and the most popular model. It is recommended for most applications including forklifts and lift trucks.
#2000C This medium height (0.95″) cap has a larger opening for easier watering and level checking. The extra height reduces the potential overflow of battery electrolyte that may be caused by vehicle motion, steep terrain, etc. This cap is recommended for golf carts and recreational vehicles (RVs).
#2000EX Our tallest (1.13″) model is recommended for battery arrays used for power storage applications (solar, wind, etc.) It provides maximum protection against potential overflow and helps assure the battery top will remain dry. May not be suitable for spaces where the clearance height is limited.

You have so many battery caps. What are the main differences between them?
The main difference between models is the optional feature or combination of features that each model includes. Here is a list of all available features:
Flame arrestor included or not included.
The flip-top feature is included or not included.
Water Miser technology included or not included.
Mount type: Bayonet style or push-in.
Height option: short, medium, or tall.

How do I choose which battery cap I need?
If you know what features you want, you may choose a battery cap by selecting a part number in the list below. The list contains all models that we currently produce, and displays what features are included in each model.

Battery Vent Caps Chart

How do I install a battery vent cap?
That depends on its mounting type. We manufacture two types, push-in, and 1/4-turn bayonet.
Push-in caps are installed by pushing them into the battery vent cap opening. They must be pushed in all the way until they are seated to assure a good seal. Some of our push-in cap models include an O-ring seal to prevent any leakage of the electrolyte. Other models are self-sealing and do not require an O-ring.
To install a 1/4-turn bayonet cap, insert it into the battery opening and twist it 1/4 turn clockwise until it tightens against the seal, or until it hits the built-in stop which prevents over-tightening. Our bayonet-style battery caps include a rubber seal to prevent leaks.
To install our threaded adapter, first, insert the bayonet cap into the adapter, then twist it 1/4 turn clockwise until it tightens against the seal. Then screw the adapter into the battery by turning it clockwise until it tightens against the seal.
To install our push-in adapter, first, insert the bayonet cap into the adapter, then twist it 1/4 turn clockwise until it tightens against the seal. Then firmly push the adapter into the battery until it is seated.

Should I buy a vent cap that has a flame arrestor in it?
If you are concerned about safety, you may want to consider it. A flame arrestor only adds about 50 cents to the retail cost of a battery vent cap.

How do I check the battery water level?
That depends on what type of vent cap you have. Some vent caps must be removed from the battery to check the water level. Flip-top caps have a hinged top that can be flipped open to check the water level and add more water without removing the vent cap from the battery. Most batteries should be filled until the water level is approximately 1/4” below the bottom of the vent well. We manufacture a battery water level indicator, and it is mainly used on industrial batteries (forklifts, golf carts, solar battery arrays, etc.), not on car batteries. When filling a battery, it is recommended to use only distilled water because impurities in the electrolyte can shorten the life of the battery. Sulfuric acid should never be added to a battery. A battery loses only water due to evaporation because sulfuric acid does not evaporate.

Do you sell battery speed caps?
Yes. We currently manufacture 3-gang and 4-gang speed vent caps. They are available for purchase on our website.