How To Charge A Second Battery While Driving

There is no better feeling than travelling off-road and camping in the middle of nowhere. One thing that can ruin this feeling is waking up in the morning, and your car battery is flat from powering your lights and other electronics overnight.

To prevent this from happening, many will install a second battery known as an auxiliary battery. Let’s explore different dual battery systems and how you can charge your second (auxiliary) battery while driving.

How To Charge Your Second (Auxiliary) Battery While Driving

Whether you decided to install a lithium, calcium, lead-acid or AGM battery, a dual battery charger is the optimal way to charge your second battery.

A dual battery charger is a device installed either in-cabin or under bonnet in the engine bay that converts power from your vehicle's alternator or main battery to a suitable voltage and current to optimally charge your secondary battery.

The dual battery charger has a built-in isolator that prevents your second battery from drawing charge from your starter battery when the vehicle is turned off. Without an in-built isolator, if your car was parked and turned off, the auxiliary battery will take charge from your starter battery, which can run your battery flat.

What Are The Dual Battery System Components?

To create an effective dual battery system, you should have:

A second battery - such as a deep-cycle lithium battery
A dual battery isolator - to prevent the second battery from drawing charge from your starter battery
A dual battery charger - takes charge from your alternator and converts it to the optimal current and voltage to charge the secondary batteries optimally.

Other Ways To Charge A Second Battery

Using Solar To Charge A Second Battery

Another way to charge your second battery while driving is to get solar panels. Solar panels can be mounted to the top of your vehicle and charge your secondary battery while driving.

Solar chargers harness the power of the sun, converting it into DC power. Solar charging relies on unblocked and consistent sunlight to generate power.

To use solar panels as a battery charger, you will need to purchase a solar regulator. A solar regulator ensures that the right voltage is supplied to your second battery to prevent long-term damage when using solar panels. Some models of DC-DC chargers come with in-built solar chargers, providing more flexibility in power source.

Get The Best Auxiliary Batteries And Chargers With REDARC

Take away the stress of worrying about flat batteries with REDARC’s dual battery chargers. Charge your secondary battery while you drive and enjoy off-grid power from the second battery at your campsite.

If you have any questions, our expert staff are available to help you. Contact us today and begin your camping adventures.

Charging Your Second Battery FAQ’s

Can you charge a second battery while driving?

With a DC-DC dual battery charger, you can charge your auxiliary battery while you drive. REDARC’s dual battery charger has an in-built isolator that stops your auxiliary battery from drawing charge from your starter battery so you never have to worry about a flat battery.

Does the main battery charge the auxiliary battery?

The main (starter) battery gets its power from the vehicle alternator. The auxiliary battery is then added to your dual battery setup and draws its power from the main battery. To effectively charge both your main and auxiliary battery, a dual battery charger regulates and delivers clean and efficient power to both batteries while prioritising the vehicle starter battery. Only once the starter battery has recharged will the dual battery charger pass current to the second battery.

Will dual batteries hurt my alternator?

If your dual battery system is set up correctly (specifically the wiring), having a dual battery charger will not hurt your alternator. This is because the power supply from your main battery is then used to charge your auxiliary battery. When a battery charges, it has a float stage that keeps the batteries topped up, this prevents the battery from overusing the car’s alternator.