One 36V Battery Or Three 12V Batteries? The Pros And Cons | BSLBATT

8,671 Published by BSLBATT Dec 02,2020

Years ago, when an application required 36 volts, the best option was to connect three 12V batteries in a series. But now that 36V batteries have shown up on the market, you might be wondering if using just one battery might “float your boat” better. (Literally, for those who need them to power their trolling motors!)

This article will be of particular interest to anyone looking into buying or that owns an electric outboard motor. Electric motors come in many different sizes, the smaller ones are generally 12 volts while the bigger ones with more thrust are usually 24 volts, and then there are the really big ones which are usually 36 volts.

One 36V Battery or Three 12V Batteries

Series Circuit

Now some of you may be thinking that you have never seen a 36-volt battery, and you would be quite right. If you require 36 volts, you will need to link three 12 volt batteries up in a series circuit to obtain the higher voltage.

So in a series circuit, we can increase the voltage by the number of batteries. 3 x 12 volt equals 36 volt, or 2 x 12 volt equals 24 volt.

When linking batteries in a series circuit you will only increase the voltage, not the amp hours available. For instance, if the 12-volt batteries used were 100 amp hours, the total amp hours for a 36-volt circuit would still be 100 amp-hours.

Series Circuit Diagram

Series Circuit

To link batteries in a series circuit, get your batteries and battery connectors and cables ready, and ensure that there are no appliances or anything else hooked up to the batteries. Take your battery connector cable and run it from the negative terminal on one battery to the positive terminal on the other battery.

To run your higher voltage appliance, attach the red or positive cable to the empty positive terminal on one of the batteries and that should leave you with an empty negative terminal on the other battery to which you will attach the black or negative cable.

Here’s an example. Let’s say your trolling motor or other application requires 36 Volts and 50AH. You can swap a single 36 volt 50AH battery for three 12V 50 amp hour batteries wired in series. But is that the right way to go?

It depends on what you need to power, the type of battery you’re using, and your personal preference. First, let’s take a look at how battery type might affect your choice.

What type of 36-volt battery are you using?

For certain battery types, choosing between three 12V batteries and one 36V might make more of a difference. For example, lead-acid batteries need to be checked often and topped off with distilled water, so you might prefer keeping an eye on just one battery instead of three.

But if you’ve chosen lithium, you’ll cut out maintenance altogether. So maintaining batteries won’t be a factor when it comes to deciding between three 12 volt batteries or one 36 volt battery.

And speaking of lithium…as the latest technology in batteries, it’s superior in every way. Both three 12V batteries and one 36V lithium battery will provide power for twice as long as conventional batteries.


Here are some of the other benefits you get just by choosing lithium:

● No maintenance needed.

● Faster charge time than conventional batteries (2 hours or less).

● Toxin-free, won’t leak, and safe to store indoors.

● Three 12V lithium batteries or a 36V lithium battery will weigh 70% less than similar setups of other battery types.

● Amperage remains consistent even when below 50% battery life.

● The discharge rate when not in use is only 2% per month (The rate is 30% for lead-acid batteries).

Three 12V lithium batteries vs. 36V lithium battery

Ok, so you’ve chosen lithium. Now let’s get to the question at hand. Should you use a single 36V battery to power your trolling motor/other application? Or three 12V batteries?

Truth is, both options work well with lithium! So you could say the only “pros” and “cons” are based on application-specific needs and personal preference. Here’s a breakdown of the difference between using a 36-volt battery vs. three 12 volt batteries:


Pros and Cons of Using Three 12V Lithium Batteries

Pros: One argument for using three 12 batteries in a series is that if one of them fails, it’s easy to replace. Also, you have more flexibility when placing the batteries in your application. This may be useful for those who want to distribute weight in a boat.

Unlike a 36 volt battery, you won’t need a special charger for your 12V batteries. They’re also engine start assist capable.

Cons: The more batteries you have, the more connection points you have. You’ll have to mount and connect each one, and each exposed connection is a potential source of unreliability.

Pros and Cons of Using One 36V Lithium Battery

Pros: The most obvious advantage of choosing a single 36V battery is, well, it’s only one! One lightweight battery (if it’s lithium) to install and store. Just one set of cables to hook up, fewer connection points to worry about, and less clutter to trip over.

Another pro is the fact that 36V batteries are “plug and go”. You don’t have to figure out how to link three 12V batteries together in a series to obtain the higher voltage.

But the most important advantage for many might be the fact that using just one 36V battery saves space! That’s great for fishing boats, where every inch of space counts. It’s one reason why they’re popular for use with high powered trolling motors.

Cons: You’ll need a special charger for a 36V lithium battery. 12V chargers are more common on the market, but they won’t cut it.

marine lithium battery

Fishing Poles On Bass Boat

Other considerations

What about the price of a 36v battery vs. three 12v batteries? Will one option set you back more hard-earned cash than the other? Probably not. While 12V batteries are less expensive, you’ll have to purchase three of them to get the power you need. And unless you’re needing a new charger to accompany it, the cost for a 36v battery is only slightly higher.

The bottom line is that both choices work just fine. There isn’t a huge difference between using three 12V batteries or one 36V battery as far as advantages and disadvantages go, as long as you’re using lithium. Choose the setup that works best for your application and needs.

And here’s some more good news: we’ve got both options! Shop our new 36V lithium battery here, or check out 12V lithium batteries here.

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