Everything you need to know about running dual batteries

Why would someone want to run dual batteries in their car? Well, that’s because running another battery allows for a heap of new possibilities that are simply not possible otherwise.

If you ever wish you could run a fridge on a camping trip, keep safety lights going, or maintain a radio connection when you’re on a worksite, then a dual battery setup could be exactly what you need to get what you want.

 

What is it?

Keeping it simple – a dual battery system allows the user to run two batteries within their car, with the second battery being used to power extra gear and accessories.

 

How does it work?

For anyone that is new to this type of thing it can be a little difficult to understand how this could work. The trick is to recognise that even though you have two batteries in the car that could be operating at the same time for the same tasks, they are actually treated as two isolated systems. 

One battery is used in conjunction with the alternator to get the car up and running, and your other battery is used when the car is off to keep all your gear going.

Here, it’s also important to note the way you’ll typically use the battery that runs your gear. That is because for something that is always being used, charged, and discharged you’re going to want to use a deep cycle battery. This type of battery is designed for that type of workload without damaging the battery itself.

This trick is accomplished using an isolator that disconnects one battery when the other one is needed. Doing this with the batteries allows each one to work independently and ensures they are always kept charged correctly. Otherwise, you can run into issues where the battery you’re using to start the car is drained.

It is possible to have an isolator that would let both batteries work together, but that isn’t always the case and is mostly dependent on the isolator you’re using in your car. However, it can be a useful little piece of tech for when the battery you use to start the car is running low and needs a little help.

 

Why you should think about running dual batteries
1.     You want a spare battery for when your first battery goes flat
2.     You’re interested in exploring solar power/charging and need somewhere to store that power
3.     You use a winch and need extra power in a pinch
4.     You want to run a fridge, lights, radio, or anything else when the car is off
5.     You don’t want to worry about being able to start the car

 

Reasons this might not be for you
1.     You don’t want to deal with the added weight
2.     You don’t want to spend anything more than is necessary

 

Types of batteries

·      Lithium – Less weight and very durable with a huge capacity. But keep an eye on the restrictions for where you can mount these, as they generally can’t go in the engine bay under the bonnet

·      AGM – These are handy because they won’t let out any unwanted or dangerous gas when they’re charging. But not necessarily the best when used as they are only really meant for partial use and recharging

·      Lead Deep Cycle – These can go under the bonnet or wherever else in your car and they are cheap. But you need to discharge these when you’re using them to keep their optimal lifespan

 

Installation

There are a couple of basics that apply to every dual battery installation. It is best to get someone professional to do the installation though, as every install is going to be different.

If you are looking into it, be sure to remember these tips:
1.     Test – Get familiar with a multimeter as this will tell you whether your system is working
2.     Disconnect the original battery before installing the second
3.     Earthing – Don’t forget to earth your second battery and the relay
4.     Look out for opportunities to waterproof – This is important because you don’t want water messing with either of your batteries
5.     Cut any unnecessarily long cables down to better fit their purpose

 

But, most importantly, you need to focus on where you will be mounting your second battery.

This is also where Auto Parts Supply can help – We stock amazing dual battery trays that can help get your sorted!

Check out our range by clicking here or get in touch over email at sales@autopartssupply.com.au