Dual Battery Systems for Cars, 4 by 4’s and Campers

Dual Battery Systems for Cars, 4 by 4’s and Campers

A dual battery system is important for anybody who wants power out in the bush without the possibility of running your main battery flat. For example many campers will have a portable fridge, and keeping the fridge running while the vehicle is parked was  simply drain your main power source very quickly.  a camper may have other power needs such as lights radios another electric utensils, all of which need a reliable power source. This is where a dual battery system is essential.

 Some 4 x 4,s  will have included a space for an extra battery in the engine bay which is usually as strong metal tray designed to carry a heavy battery load. However if this extra space is not included with a few modifications we can make space for the extra battery.

 Basically what you want are the two batteries separated, want to run the car and the other to run your Utilities like your fridge and your mobile telephone and your mobile computer. While your car is driving it would be charging up both batteries. While the car is stopped the two  batteries are separated leaving one battery isolated for the car and the other available to  run your fridge and utilities. An automatic solenoid switching unit is usually used for this purpose and in some circumstances the second battery can be used to jumpstart your car by doing so will override the solenoid. There are disadvantages to the system however and a manual switching method may provide a safer system you can rely on.  The manual system would allow your  2 batteries to be either used to start the vehicle or power your utilities and equipment while at the same time completely isolating the other battery which is not being used. This also avoids the risk of flattening the other battery. The batteries can also be used in parallel which can be used to provide the extra power required to operate a winch for example.

 So  in short there are two isolators you can use, a basic isolator and a smart isolator. The basic isolator is really just a switch, a manual switch which connects the two batteries together and is controlled not by yourself but the ignition of a car the basic purpose is to isolate your starter battery which provides a safe way to use the second battery until it’s flat if necessary. The  trouble is when you start your car the flat and the battery also connects and there may not be enough power to start the vehicle. On the other hand as smart isolator works differently and turns on and off depending on the voltage and will keep the secondary battery isolated until your main starting battery is fully charged.

 Some other considerations with your batteries are the two different kinds of batteries you can purchase. The simple starting battery will provide a high shot of energy to easily start your car where is a deep cycle battery does not have as much instant power but will  last a lot longer and is designed to be used where the battery can be almost flat and recover completely after a good recharge. Of course a normal car battery will not provide this kind of power and you cannot run your battery to very low levels without permanent damage.


 Most cars run on lead acid batteries you find them in most vehicles and they are relatively inexpensive and as the name suggests they are full of acid and should be kept in an upright position.

 Another type of battery is the absorbent glass mat or AGM. The way these batteries are constructed provides a leak-proof method of power supply which means that can be installed and fixed at any angle and inside the cab of necessary. The rate of discharge  slow so they can be left for quite a while without being charged but they are not suitable to start a car but they are good for chatting up your utilities your friends your mobile telephone and your mobile computer.

 A gel cell battery is usually a little more expensive then the AGM batteries. They don’t use liquid acid which has been replaced with a gel acid. You can’t spill the acid and they do not need any maintenance. Again these batteries are not really suitable to start your car but are ideal for all your Utilities.

 There are many variations of dual battery systems and our advice is to speak to one of our technicians to discuss your exact requirements. We can provide advice on which system will provide you with the most efficient service, how to look after your batteries convertible how to get the peace of mind you need before you go on a long trip where you may not have the backup and services to keep you going with your power requirements.

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