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What battery charger do I need?

Here at REDARC, we say the battery is the heart of a dual battery system. It stores and provides the essential power to operate all of your auxiliary powered devices. But just like any other product, there are some crucial points that require closer attention when setting up your ideal dual battery system.

In this blog, we take a closer look at battery specifications and charging requirements so that you are armed with all the helpful knowledge when you’re looking to set-up your dual battery system.

The importance of battery specifications

The battery specifications are the first thing many people over-look. These specifications define many things when choosing the correct product to charge and maintain your auxiliary battery.

These specifications outline the limitations to what the battery can do. Exceeding the specifications can dramatically reduce battery life and even cause premature battery failure.

Three main specifications that you should pay attention to when selecting a dual battery charger for a specific battery are;

  • Battery type e.g. AGM, Lead-Acid, Lithium (LiFePO4) etc
  • Maximum Charge Voltage
  • Maximum Charge Current

How to choose the right vehicle battery type

Each battery chemistry reacts differently when being charged and are required to be charged in a specific way. The charge profile consists of a maximum charge voltage and will provide the battery current in the correct way to ensure the battery recharges to 100% SOC. Charging the battery in these ideal conditions will not only maintain the battery but extend its lifecycle.

What is Maximum Charge voltage?

Maximum charging voltage identifies what the highest acceptable charge voltage the battery can take to charge the battery.

Maximum Charge Current explained

Maximum charging current identifies the highest amount of charge current that the battery can receive when charging the battery.

It is critical to charge the battery within the specifications of both maximum charge voltage and charge current, otherwise, you can drastically reduce the batteries health and life and even cause premature battery failure.

How to calculate the best battery charger for your dual battery setup

Let’s run an example.

Say you have a 100Ah Lithium battery with a maximum charge voltage of 14.6V and a maximum charge current of 50A. This means the charger of choice must not exceed the manufacturer’s specifications and must meet these requirements to ensure the battery is charged and maintained to 100% state of charge (SOC).

The charge profile must suit a charge voltage of 14.6V and not exceed 50A charge current.

Therefore, an in-vehicle charger that is rated up to 50 amps would be recommended.

AGM batteries in your common size 100-120Ah would have a maximum charge current spec of 30-35A, therefore the 25amp BCDC1225D charger would be recommended.

Lead Crystal batteries on the other hand generally require 30% of the total amp hours in charge current (manufacturer recommendation), in which case the 40amp BCDC1240D battery charger would be suitable for 90-130Ah.

Making it simple

There is a lot to think about when selecting the right charger for your dual system. The most important thing is to look at the maximum charger current specification on the battery and choose the correct charger for the application.

Luckily, we have made it simple. Our dual battery charger range features 4 different charging profiles (A, B C or Li for lithium) designed to suit your battery’s charging requirements and will suit all battery makes and models.

What’s more, our vehicle selector provides you with a recommended charger based on your vehicle, battery information, and usage information.

Regardless of which charger you choose, you’ll be assured one of the REDARC battery charger range will get you where you need to go and back again reliably and safely. 

Take the REDARC Hilux product tour to find out what products are best for your overlanding, power management and towing needs.