In-Vehicle Battery Charging

By Joe, Sales Representative for KickAss

2 Minute Read


By now you have had your new kickass battery for a few weeks and you may or may not have had a chance to test it out. There are various ways of recharging your battery after use and there are more and more ways being introduced & updated quite quickly as the industry grows.  One of the most common and convenient ways of recharging your batteries these days is via your vehicle.


Most of us use our vehicle’s every day so it makes sense that instead of having to charge our batteries at home using 240v chargers, we can let the vehicle do it for us. But why do we want to charge our batteries from our vehicles and how does it work?


It’s very common for people to run fridges and appliances from their vehicles. Up until recently, you would have to have the ignition on to run your appliances so that they wouldn’t flatten your starter battery leaving you stranded. The solution that has been put in place is to have a dual battery to run your appliances so that you don’t have to have your car on, or worry about a flat battery. This has been a great substitution but maintaining the second battery requires a source of charge so it too, does not go flat. Listed below are some common ways of charging your battery in-vehicle;



A VSR or Voltage Sensitive Relay is the most common and basic way of charging your battery from your car. This unit consists of a relay that opens and closes the circuit at specific voltages, allowing for your alternator to charge your second battery at the same time and then disconnect once the car has been turned off to ensure you don’t end up with a flat starter battery. These units work perfectly on all vehicles up until around 2007 when emission control measures affected the output of vehicles alternators, the consequence of this is that secondary batteries will never get a full charge using a VSR.


Dc/Dc Charger

When smart alternators were invented a new solution to in-vehicle battery charging was needed, this is how the Dc/Dc charger came to fruition. A Dc/Dc charger is the next step up from a VSR and allows for both solar and your vehicle to charge your secondary battery at a quicker rate than a vsr due to the Dc/Dc’s ability to increase the amperage of your alternators output. Dc/Dc chargers are considered smart chargers due to the way they monitor the battery while charging it and adjust their output to fit exactly what the battery needs at the current time. They are able to switch between multiple modes of charging including bulk, float and maintenance stages to keep your battery in the best condition it can be in. These are also required for newer cars with smart alternators as these alternators do not work well with VSRs due to the quick voltage variances.



When a solar panel is connected into an in-car charging system, it provides an extra boost and can allow for your car system to charge even when the car isn’t running. This is a very common addition for tradesmen working in more rural areas. It can run their fridge, lights, charge their tools and not flatten the battery due to the constant solar input.  This is also very useful when camping with your car away from power, the solar panels will keep you running even while you’re relaxing at camp. Solar panels are normally run through a regulator or Dc/Dc charger to the second battery in the system.


Now that you now know about in-vehicle battery charging and maintenance, there should be no way that you’re auxiliary battery should ever go flat! Having a charging option attached to something like your vehicle allows for a plethora of different opportunities. Not only can you go out camping or four wheel driving on weekends with all the comforts of your own home, with the right set-up you can go indefinitely. For the average Joe, having an in-vehicle battery charging system means you don’t have to worry about taking your battery in and out every couple of days to charge your battery. This means that dream holiday or weekend getaway will go off without a hitch and you won’t have to worry about a thing.


As usual, we care about what you guys do so send us a clip of your KickAss set up. Alternately, just drop us a line or review in the comments section below or on Facebook, we would love to hear your thoughts.

Happy caravaning, camping and 4X4 from the KickAss Team!