How To Avoid Caravan Battery Drain

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We tend to take electricity for granted, but caravan battery drain can quickly put a hole in your holiday plans. Let’s look at how you can prevent it happening.
As soon as the trailer plugs connected between your caravan and the tow vehicle, power will flow from the car battery to appliances such as the refrigerator. It’s not the vehicle moving that’s the problem – because the battery is constantly recharging – it’s when you’re parked on an unpowered site that you can run into trouble.
How to drain a battery… not
Certain appliances will cause high battery drain – heaters and air conditioning units are notorious guzzlers – so make a habit of turning off and unplugging anything that’s not being used. These steps will also help:

  • Invest in a dual battery set-up, which isolates the starting battery from your caravan; the refrigerator and other 12V appliances run off the second, usually deep-cycle battery.
  • A dual battery controller disconnects the car battery when it detects that the car voltage has gone below 12.6, the resting voltage of a normal car battery.
  • A caravan fridge will drain the tow vehicle’s battery unless it is isolated when the vehicle is stationary. For less than $60 you can buy a fridge switch, which detects motion and will turn the fridge ‘off’ the car battery when the vehicle stops.
  • Have the battery serviced regularly and keep the terminals clean.

What to do when it happens
If you suspect your vehicle’s battery is flat, unhitch the caravan before attempting to start the motor, to prevent further drain. Then you have several options, depending on the situation:

  • If there are other vehicles around, jump-start using good quality jumper cables.
  • Contact your road service provider, who will either replace or top up the battery.
  • Have a tow truck take the vehicle to the nearest service station for recharging or replacement.

What if it keeps happening?
If the battery keeps going flat when the caravan is hitched, there could be problems with the battery itself, or a leak somewhere.

  • First, check for leaks. Make sure all lights are turned off and appliances are unplugged, then test the fuses using an automotive current tester, which will identify any leaks.
  • When was the last time you had the battery serviced? Maybe it’s time to replace it with a new one.
  • Have an auto electrician check for faulty wiring in both tow vehicle and caravan.

The best way to avoid battery drain is to keep both the battery and wiring in top condition, reduce your reliance on electricity and remember to unplug any appliances that are not in use.
AGM or gel: which is the right battery type for your caravan?


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