Can I Use a 12v Charger for 6v Battery

Published on: May 12, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

A smaller 6-volt battery system is used in several recreational vehicles, motorbikes, mobility devices, and other similar equipment. But sometimes, users have a 12V charger instead of 6V and wonder if I can use a 12v charger for a 6v battery.

According to logic, a 12V charger will charge a 6V battery twice as quickly as a 6V charger. While that makes mathematical logic, the reality is that this can be highly harmful in some cases.

can i use a 12v charger for 6v battery

Battery chargers conserve the static energy in a secondary cell battery. When a battery is discharged, the electrolyte in the battery reacts with the electrode material, resulting in crystal forms on the electrode surface. Applying an excessive amount of voltage to a battery will cause the electrolyte to overheat, which will result in the battery being damaged.

Battery chargers work by reversing the chemical reaction that results in the formation of crystals, thereby regenerating the battery. Listed below is all you need to know about using a 12-volt charger properly to charge a 6V battery

How Do You Charge a 6-volt Battery With a 12-volt Charger?

You can charge your 6V battery with a 12V charger by following the step-by-step instructions provided below.


Take off the battery clamps and snip off around four inches of wire from each one. Remove the electrical tape from the previously connected wire to the positive battery clamp to distinguish it from the other wire. Remove roughly a half-inch of insulation from the battery clamp and battery charger wires once they have been snipped.


Make a solder bridge between the positive battery charger cable and one of the first resistor’s leads. After the soldering junction has cooled, cover it with a piece of electrical tape until it is no longer hot. After that, connect the disconnected resistor’s free lead to the positive battery terminal wire and the free lead of the first resistor. When the joint has cooled, secure it with electrical tape.


Make sure to connect both negative battery and charger wire ends of the second resistor’s free lead with solder. When the soldered junction has cooled, secure it with electrical tape.

In lieu of this, you should use a charger that allows you to control the voltage. Using this method, you may rest assured that your battery is always fully charged. 

What Voltage Should I Charge a 6v Battery?

A battery is composed of several cells, and the lead-acid chemistry specifies that each cell should have a fully charged voltage of approximately 2.12 volts. As a result, a nominal 6-volt battery has three compartments, each with a full charge voltage ranging from 6.3 to 6.4 volts.

A greater cell voltage can be seen in high-quality and high-performance lead-acid batteries. A lead and a lead dioxide liquid are used in the cell to keep the sulfuric acid electrolyte in touch with both plate types. A mat or gel absorbs the lead oxide plate type.

So if your vehicle or equipment has a 6V battery, make sure you have the same 6-voltage charger on hand. This can help safeguard your batteries and avoid significant harm from improper charging. 

Can You Use 6v and 12v Batteries Together?

You can’t just connect a 12-volt battery in series with a 6-volt battery. Only batteries of the exact same brand, chemistry, and term can be paralleled. Otherwise, charging will be uneven, reducing battery life. Temporary parallel interconnects can be used as a starter-generator or other quickie jumper.

If you leave the 12-volt and 6-volt batteries connected in parallel for more than a few minutes, the batteries will attempt to equalize the charges between them, which will reduce their battery life. However, this should only continue for a few seconds.

Can I Use a 6v Charger for a 12v Battery?

A 12-volt battery can be recharged using a 6-volt setting with little difficulty; however, it will take double the time. Using the same example, charging a dead 12-volt battery with a 12-volt charge can take anywhere from 12 to 18 hours, whereas charging a dead 12-volt battery with a 6-volt charge can take anywhere from 24 to 36 hours.

You will never fully charge your 12V battery when using a lower voltage charger since the voltage is too low. It might be able to charge your battery sufficiently to allow you to jumpstart your gadget, but that’s about it. It’ll still be necessary to locate a battery charger compatible with your device to continue using it after that.

Relation Between Battery Capacity and Size

Reserve Capacity (RC) is a battery capacity measurement that measures the battery’s remaining life in minutes. Specifically, the amount of time a battery can supply 25 amps at 80 degrees F before the voltage falls to 10.5 volts for a normal 12-volt battery and 21.5 volts for a standard 24-volt battery is referred to as the “reserving capacity.”

As an approximation, the following formula represents a relationship between amp hours and the reserve capacity: ah is equal to RC divided by 0.6. Below is typical battery voltages and AHs:

The Voltage of Battery(V)The AH of Battery(AH)

Can I Charge a 12V Battery with an 18V Charger?

You may charge a 12V battery with an 18V charger easily. But as the solution seems straightforward at first glance, it is not. If you do so, the battery will heat up quickly and charging it this way is riskier than using a standard charger since you can’t monitor the charge condition.

Charging a lead-acid battery this way is even worse than using a traditional charger. Using a 12V battery, you can run a 24-volt appliance. The battery should not expand when charging, and no gases or vapour should be emitted during charging; if any of these things happen, the charge should be stopped immediately.

When charging, keep an eye on the voltage as well as the battery’s level of charge. It’s important to realize that charging the battery this way can reduce its lifespan. The majority of modern chargers, on the other hand, provide charging with a fully controlled current; thus, they may be used to charge an automobile battery, regardless of nominal voltage.


The charger and the battery properties will determine whether or not it is safe to use a 12v charger for a 6v battery. But overall, we hope in this article we give you the practical scenarios which clear all your doubts about Can I use a 12v charger for a 6v battery?’ Neither your 12V nor 6V batteries are charged to their full rated capacity due to your current charging configuration.

Depending on the cause, it might be due to the charger itself or the charging method employed; or it could be due to the batteries themselves being old or heavily used and therefore unable to retain a full charge anymore. 

But the most efficient method of charging a battery is to use a modern charger with a CPU, which allows the device to determine the correct current and voltage level while also controlling it in real-time. Remember that electricity is a valuable and powerful force, and we must all use caution when working with or around it.

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About This Writer

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Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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