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

From my personal 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. 

Even though you can mix batteries, it isn’t the best thing to do for your cart if you want the overall battery power to last. In this post, I want to explore some of the reasons it’s not the best idea and help save you money down the road. 

Can You Mix Old and New Golf Cart Batteries?

There’s a huge gulf between can you mix batteries in a golf cart and should you mix batteries in a golf cart, so should you?

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

Can you Replace Just One Battery One A Golf Cart?

The thing is, batteries lose power at different rates. If you happen to 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 definitely pop up to suggest that you don’t have to spend all that money; you can just do the “sensible thing” and replace the bad battery with a single battery.

Though you can do it, it 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.

Why Combining Old and New Batteries is Problematic

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

This is because the newer, more powerful deep cycle batteries will start to supply current through the older, decrepit 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, and of course, it will not be the manufacturer’s fault. If these spontaneous battery acid discharges and makes it through to the electric motor, it could spell sayonara to your motor. 

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 you issues with securing the pack to the battery terminals. Yes, this depends on what type of battery storage is provisioned in the golf cart, but it’s an entirely 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 will gradually grow in significance until you’ve got yourself 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 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 of time. 

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. Make sure that units in a battery pack will all expire around the same time.

Some dodgy outlets create their own battery packs and, of course, “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.

Knowing When it is Time to Replace Batteries

Knowing when it is time 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. Batteries 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 just have to suck it up and do what’s best in the long term for your golf cart and your pocket.

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 the life of luxury with your own cart, you will have to deal with the maintenance costs involved. 

What to do next…

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

Click here to check out the maintenance checklist!