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 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” 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 don’t see a vent cap that will fit my battery. Do you make an adapter for battery vent caps?
Yes, we make several adapters. They will adapt a quarter-turn bayonet cap to either a threaded type or a push-in type battery orifice. You can view the adapters here.

Which of your battery caps are the most popular?
Our basic vent cap models are the #1050 and #1070. Some battery manufacturers use the #1050 on their high production batteries due to its 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. The Water Miser technology reduces evaporation, saving time and maintenance costs. It also contains a flame arrestor which has the added benefit of reducing toxic battery fumes in work areas. It is available in three different heights, and the differences between part numbers are explained below.
#2000 This is the shortest (0.63″) and 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 added height reduces the potential overflow of electrolyte that may 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.
Flip-top feature 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 select a battery cap by clicking on the part number in the list below. The list contains all models that we currently produce, and displays what features are included on each model.

Part #Mount

How do I install a battery vent cap?
That depends on its mounting type. We manufacture two types, push-in, and quarter-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. Our push-in caps include an o-ring seal to prevents any leakage of the electrolyte.
Quarter-turn bayonet caps are installed by inserting them into the battery opening, and then twisting them clockwise one-quarter turn until it tightens against the seal, or until it hits the built-in stop which prevents overtightening. 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 clockwise one-quarter turn 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 clockwise one-quarter turn 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.  Click here for more information.

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 which 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 ¼” 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.