Why Do Golf Cart Batteries Swell? 

Golf cart batteries fulfill a simple task, but the way they do it is complicated and demanding. Because of the intense stress that gets put on golf cart batteries, they’re prone to a number of issues. One of the biggest problems and hazards you can run into with your batteries is that they start to swell or bulge. 

Golf cart batteries swell for various reasons, the most common of which is that you have a battery acid leak. However, golf cart batteries can also swell if your water levels are off or because of excessive heat. Swelling is never a good sign with your battery and will usually precede cracking and bursting. 

While leaking acid, overheating, and overcharging are the most common culprits for a swollen battery, they aren’t the only ones. This article will look at seven of the most common causes of a swollen golf cart battery, as well as what to do about them. Finally, we’ll discuss what to do about swollen batteries and how to prevent swelling. 

7 Things That Can Cause Golf Cart Batteries to Swell 

The Battery is Leaking Acid 

Corroded Golf Cart Battery
Golf Cart Battery Leaking Acid and Swelling

One of the leading causes of battery swelling is because of leaking battery acid. Leaking acid usually means that one of your battery cells has burst within the battery. There are a number of reasons that this can happen and we’ll discuss them later in this article. 

Repeated Overcharging 

If you’ve ever felt your charger or charger cables while charging your golf cart, you probably noticed a ton of heat coming from these components. While heat is perfectly normal during charging, too much is a bad thing and is usually the result of overcharging. 

You don’t have to be a scientist or chemist to understand that heat causes things to expand. This is especially true in an enclosed space such as a battery. Therefore, if you overcharge your golf cart battery often enough, the excessive heat will eventually cause the sides to expand. While this won’t affect the performance of the battery at first, it’s a safety hazard because the sides will eventually split and crack.  

Charging With Low Water Levels 

If you repeatedly charge your golf cart battery and it has low water levels, it can cause sulfation, which is the formation of lead sulfate crystals. If enough lead sulfate crystals form because of sulfation, it will cause your battery to swell and bulge. Therefore, it’s crucial that you check your water levels frequently to keep this from happening. 

Water Levels are Too High

In the same way that low water levels can cause swelling issues, so can high water levels. The way that most golf cart batteries work is that the water gets converted to hydrogen and oxygen. As this process takes place, the water will expand. If there isn’t enough room for expansion because you overfilled the water compartment, it can cause battery swelling. You should always leave a quarter of an inch of space between the top of the battery and the top of the water. 

Clogged Vent Cap 

Because golf cart batteries produce small amounts of hydrogen and oxygen gas, they’re equipped with small vents to expel these gases. If one of these vents gets clogged or isn’t opening properly, gas will start to build up inside the battery. Not only will this cause the battery to swell, but it will also turn it into a fire and explosion hazard. If the gases catch fire, swelling is the last thing you’ll be worried about. 

Swollen Battery Cells 

Golf Cart Battery Swelling

In most cases, individual battery cells can swell if there is too much current flowing inside of them. Swollen battery cells are a big problem because they’re difficult to spot at first. The cells are inside the battery, which means you won’t notice swelling until the problem is so bad that the cell is pressing against the outside of the battery. 

By that point, however, the cell is beyond repair and likely completely destroyed. While the reason for swollen battery cells is because of excess electrical current, there are several things that can cause this to happen. 

  • Physical damage to the battery 
  • Overcharging 
  • Allowing the battery charge to get too low 
  • Manufacturing defect

No matter what the underlying problem is, you’ll have to replace a battery that swells because of damaged cells. 

Internal Layers of the Battery are Breaking Down

Finally, golf cart batteries have a number of internal layers that keep different things like water, acid, and gas apart from one another. If one or more of these layers starts to break down, the components are able to combine. This, in turn, will lead to swelling, bulging, and a possible explosion. 

Golf cart batteries breaking down can cause your battery wires to get very hot and melt. Here is an in depth article if your battery cables are melting.

Do I Need to Replace a Swollen Golf Cart Battery?

If your golf cart battery is swollen, regardless of the reason, you should replace it. Batteries don’t swell unless something is wrong with them. In most cases, swelling precedes complete cracking and breaking down of the battery. Furthermore, if your battery is swollen because of trapped gases, it presents a fire and explosion hazard. 

Have just one battery swelling and considering just replacing that one? You may want to read this article for the reasons why not to replace just one.

How to Prevent Swollen Batteries

The good news about swollen batteries is that they’re completely preventable. Swelling doesn’t occur naturally and is typically the result of doing something wrong. Here’s a list of tips and tricks to avoid swollen batteries. 

  • Always keep your battery’s water compartments filled to the recommended levels. 
  • Avoid overcharging your battery. 
  • Check the water levels periodically to ensure they’re full enough. 
  • When you refill your battery cells with water, leave a quarter-inch gap at the top to provide room for gases. 
  • Keep the battery out of hot areas and store it in a dry, cool location. 
  • Use the right charger for the battery and never leave it plugged in longer than necessary. 
  • Have your golf cart and batteries checked by a professional on a regular basis. 

Frequently Asked Questions 

Is it normal for golf cart batteries to swell?

Swelling is abnormal for all batteries, including the ones in your golf cart. It’s a sign that water, acid, or gas is leaking and causing expansion. 

How do I know if my golf cart batteries are going bad?

There are a number of signs to indicate that your golf cart battery is going bad, including swelling. Your battery also won’t hold a charge as well and will have less power than usual. 

Is it normal for golf cart batteries to bubble? 

Bubbling, whether in the form of swelling or in the form of a bubbling sound isn’t normal. It usually happens because of leaking gas or water and is a sign that something is wrong.