Can You Mix Batteries in a Golf Cart? (Explained)

From my experience, golf cart batteries can get expensive, so I try to get them to last as long as possible. But while I may be fixated on considering the costs of mixing new batteries with older ones, I wonder if mixing batteries this way is inadvisable and affects safety or performance.

In general, you can mix batteries in a golf cart without harming it long term, but it is not considered best practice. Combining old with new, batteries of different brands, mixing batteries by creating your own parallel or serial battery packs, or entire battery types (like car batteries) can help a cart move temporarily. 

In this post, I want to explore why it’s not the best idea and help save you money. 

Can You Mix Old and New Golf Cart Batteries?

Whatever kind of battery you choose, all batteries eventually lose their electrical charge and grow weaker until they can’t even power a child’s plaything.

Can you Replace Just One Battery in a Golf Cart?

The thing is, batteries lose power at different rates. If you test them, you might find that the power loss is due to just one errant battery in a pack.

The evil little miser that hides in your head will suggest that you don’t have to spend all that money; you can do the “sensible thing” and replace the bad battery with a single one.

Though you can do it, it is not a good idea!

The combination of old and new batteries will probably result in an unrecoverable gap in the maximum electrical capacity of the pack, significantly lessening the power available to your cart and turning your zippy little number into a frustrating and lumbering golf-link jalopy.

Different internal resistance

Imbalance in terms of discharge

Inequality in terms of performance

Higher chance of overheat

Would there be a problem if you mix old and new batteries?

The imbalance between the old and new batteries will grow more and more pronounced over time. If you’re not careful, the electrical output can be compromised to the point that you could damage your electrical motor.

This is because the newer, more powerful deep-cycle batteries will start to supply current through the older, frail ones, resulting in increased resistance from the older batteries and significantly heating up the battery pack. This is typical, especially when you charge lead-acid batteries. 

And trust me, no amount of water in the battery or fancy battery charger will level this off. 

It doesn’t stop there. Heated batteries that exceed their rating can cause random discharges and leaks; of course, it will not be the manufacturer’s fault. If this spontaneous battery acid discharges and goes through to the electric motor, it could spell sayonara to your engine. 

Mixing Batteries from Different Brands

Just as I don’t recommend mixing old and new batteries in your golf cart, I also cannot in good conscience recommend mixing different brands of batteries. The reasons are pretty straightforward and obvious when you think about it.

Batteries of Different Sizes

For example, batteries that aren’t the same physical size might cause issues with securing the pack to the battery terminals. Yes, this depends on what battery storage is provisioned in the golf cart. Still, it’s an unnecessary hassle that is easily avoided simply by buying batteries from the same manufacturer. 

Differences in Voltage

There are subtle differences in voltage and power among batteries of different types, and over time, just as between old and new batteries, imbalances that you won’t at first notice gradually grow in significance until you’ve got yourself a much bigger problem.

At the very least, you’ll have issues with your batteries in that some or all of them will be damaged, and the remaining battery life is next to nothing.

Note that I wrote “will be,” not “could be.” This damage, of which I speak, is sure to happen if this is done for a long period. 

Safety

Another problem you could run into with your mixed-manufacturers batteries is that damaged batteries will pose the same safety and performance dangers as combined new and old batteries, meaning you could end up harming your golf cart’s electric motor or other electrical systems.

Expiration Dates

By the way, always look at the expiry date before throwing them in the battery compartment. Ensure that units in a battery pack will expire around the same time.

Some dodgy outlets create their own battery packs and “forget” to tell you.

Unfortunately, what they do is not against the law, so it is up to you to do your own due diligence.

When is the time to replace batteries?

Knowing when to replace soon-to-be dead batteries in your golf cart will help ensure the cart runs effectively and safely.

• Batteries with physical issues, like bulging or leakage, must be replaced as soon as possible, no questions asked. Storms in this condition can cause leaks or arbitrary discharges that can endanger your safety if you continue using them.
• Unexplained decrease in battery capacity and/or your golf cart noticeably underperforms after getting a “full charge.”
• Failure of specific elements like the air conditioning or radio, as these electrically powered units will not have access to sufficient power if your battery isn’t working properly.

Should you replace all your batteries simultaneously?

You should replace all your batteries at the same time. Sure, it’s a bummer and pricey, but you have to suck it up and do what’s best in the long term for your golf cart and your pocket.

Do golf cart batteries need to be the same?

Because golf carts use multiple batteries, it’s essential that you make sure they use batteries in multiples of their volts. A voltage is required to meet the cart’s needed power, and replacement batteries should also be in the same volt you’re already using. It should be consistent whether it’s 6V, 8, or 12.

Bottomline

You shouldn’t mix batteries in golf because it’s not a best practice. You should buy the right battery for your golf cart.

Some people think it’s a myth propagated by greedy salespeople trying to sell more expensive options, but I assure you it’s not. When you live a life of luxury with your cart, you will have to deal with the maintenance costs involved. 

The best thing you can do now is check out my HUGE golf cart checklist. It goes through everything you need to know about caring for each part of your cart and ensuring it lasts as long as possible. 

Click here to check out the maintenance checklist!