By Erik Watkins

12V vs. 24V Difference & How To Connect 2 12V To Make 24V

Last updated: Mar 11, 2023
12V vs 24V Difference


Is 12V to 24V more efficient than 120 to 24? There is no accurate answer. The one and only reason for using higher voltage is the reduction of energy losses if you input the same power. To determine the true power of sources, you must consider their performance in a detailed comparison. If you have no idea, scroll down to learn. 

What Do “12V” And “24V” Mean? 

12V and 24V both represent a supply voltage below the nominal load. The first option is common in cars and RVs because electrical accessories such as lighting, ignition, or starter systems are well adapted to this voltage source.

Meanwhile, 24V batteries often work with bulky vehicles like buses or trucks to meet their high energy needs. It also appears in trolling trawlers or some RVs with sophisticated solar panel systems.

Differences Between 12V vs. 24V

Pros And Cons Of 12V

Pros And Cons Of 12V


The most visible benefit of a 12V system is its ease of use. It is ideal for operating DC circuits directly from batteries. In most cases, users only need to work with an additional 120V system for the AC equipment in the car and do not need to input a third source.

Most vehicles operate on a 12-volt system, which means no converters needed.

Another plus is the variety of 12V products on the market rather than 24V. There are more options to enhance the comfort inside the vehicle, such as LED lights, ventilation fans, etc., with ease.


12V systems possess an undeniable shortcoming: charge regulators are often fixed in capacity. You struggle to increase the output voltage to a higher level because chargers usually work on the opposite mechanism.

This system also requires larger wiring and controllers. As a result, buyers have to pay more for installation.

Pros And Cons Of 24V

Pros And Cons Of 24V


The 24V system came to fill the void the 12V one leaves behind. For example, it cuts wiring costs in half thanks to the smaller size of the wires. This is thanks to a basic physical principle: as the voltage increases, the current decreases (which necessitates smaller wires).

Another advantage is its universal compatibility with AC devices. Even if you temporarily need 12V power, converting from 24V using the controllers does not cause any difficulty or hassle.

Ultimately, this system deserves your attention if you intend to install a large solar array on your vehicle. Its watt supply goes up to 2900 – double that of 12V. It also come up with a smaller and cheaper charge controller to save your budget.


Car charging is the biggest problem with 24V, as most batteries start at 12V. For this reason, you have to pay for converters that boost amperage. Several individual voltage converters are also essential to provide compatible power to the 12V devices inside the vehicle.

When To Use Each One?

Unfortunately, we never get an exact answer. It would help if you determined the right option based on the consumption of your vehicle.

If your car opens to a small interior and does not hold too many electrical appliances, a 12V system handles it. However, rugged vehicles such as trucks, class A recreational vehicles, etc., require 24V or higher voltage.

24V Or 12V: Which Is Best? 

Watts Rating

Watts rating plays an important role when comparing power output. It has little to do with amperes measured in peak power as the calculation formula is based on continuous power.

Specifically, 12V batteries bear a lower watts rating than 24V. This allows the latter to expand its load level but poses the risk of damage. Meanwhile, the first suggests safe use due to the lowest possibility of an electric shock.


The electrical power of the 24V battery is twice that of its counterparts – the higher the voltage, the stronger your vehicle. However, the maximum torque and amps have a huge say to decide which to go for. A product is considered powerful when it achieves optimal performance without technical problems.

For example, a 12V battery going hand in hand with 30 amps produces 360 watts. Meanwhile, 24V items often work with 15 amps, so what is the output? That’s right; 360 watts, or in other words, both deliver the same power. 

An important note is that you should not let your item run continuously at a nominal rating. Doing so increases the current, accumulates heat, and shortens the battery’s life.


The 24V power plant uses smaller conductors than the 12V, thus allowing the power supply to occur more efficiently. This creates a speed deviation, and 24V takes the lead. It produces a top speed of about 6 mph, while the other usually runs at 4 mph.


It is not straightforward to give the results of the battery runtime calculation because there are many influencing factors, such as driving terrain, integrated features, speed, etc. 

For example, bumpy roads create greater friction with the wheels. Hence, the vehicle cannot achieve smooth overtaking through the stresses that drain the battery.

A 12V device can last about 2 hours, while a 24V can keep it running for 4-5 hours. In turn, 12V takes 6 hours to reach full capacity, while a 24V battery requires extra 2 hours to be fully refilled.


Regardless of the type, the average lifespan of car batteries ranges between three and five years under favorable conditions.

Car manufacturers often install this unit under the hood and close to the engine. Unfortunately, this location puts the battery in close contact with two detrimental factors – heat and vibration which can influence its ability to hold a charge.

If you find some of your car’s built-in features, such as headlights, power windows, etc., working below standard, the battery is likely running out of juice. One of other obvious symptoms is that the engine takes longer to start.

How To Connect Two 12V Batteries To Make 24V 

Connect Two 12V Batteries To Make 24V 

Dual 12V is widely used in performance vehicles with magnifying sound systems, towing trucks, ballast racing cars, etc. However, the wiring pattern determines whether its output is 12V, 24V, or both. Here is the general rule:

  • 12V (or 14.2V for the alternator) if you keep the batteries isolated or parallel.
  • 24V (or 28V for the alternator) if you make two batteries connected in series. Note that amps remain unchanged.

Apply the second wiring rule and follow these steps.

  • Connect the positive terminal (+) of the first 12V battery to the first battery cable
  • Connect the other end of that cable to the negative (-) terminal of the second battery. Now you have completed a part of the series circuit. 
  • Take two more cables and connect them to the two unused terminals. Ensure you maintain a certain distance between them, as the output is now 24V.
  • Take the cable attached to the negative (-) terminal in step 3, connecting to the power unit’s negative (-) terminal. Do the same for the remaining ports. 


Is A 24V Or 12V System Cheaper?

A 12V system costs you less than 24V, which adds another plus for higher power. However, it would be best to consider both sides of each option to make the right decision.

Can I Use 24V On A 12V Engine?


Theoretically, you could run a 12V motor with a 24V battery, but the output power is reduced. Additionally, you have to prepare a larger space for the setup.


Both 12V and 24V engines have advantages and disadvantages. The ultimate option depends on the compatibility of your vehicle and your demand. That said, it is a great idea to equip you with the first options to know how to make 24V from two 12V batteries. The entire process is as easy as a piece of cake, but above all, it all boils down to your preference.

Automotive Mechanic at PowerAll

With 7 years experience in management positions leading automotive mechanics at PowerAll, Erik Watkins wishes to share useful knowledge and information about automotive mechanical equipment.


Submit a Comment

Your email address will not be published. Required fields are marked *

Related Post