My 1990 Vanagon camper has an after market Kenwood radio NOT wired through the ignition circuit but instead wired directly to an auxiliary battery which also powers other domestic camping stuff like the sink water pump, reading lights, etc. This battery is charged by the alternator but we rarely use this vehicle unless we are on a camping trip so it remains inactive for long periods of time, during which I loose the charge on the battery because of the draw from the radio even when the radio is off. So my question is this, if I change the set up so the radio is wired through the ignition system will there be significantly less drain on the battery when the van experiences long periods of inactivity than I experience now by just turning off the radio? Thanks for your thoughts. Dave.

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    Most leisure battery systems will have a master switch to isolate such drains while the vehicle is overwintered. On my T2 you isolate the battery and top up the charge every couple of weeks to counteract the natural discharge of a lead-acid battery.
    – Chenmunka
    Commented Jul 1, 2016 at 7:57
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    A battery cutoff can be mounted to the battery terminal. They are inexpensive and it may help you rule out if you have a parasitic load or the battery just looses charge by sitting. Solar battery maintainers are an option, too.
    – emican
    Commented Jul 2, 2016 at 0:59
  • Thanks guys for your thoughts about adding a switch to disconnect the battery when the car is not in use. I could do that but then I loose the use of the sink pump and interior lights, not just the battery. I was thinking that if I reworded the radio through the ignition I might acomplish the same thing. We don't often use the radio when we are not driving.
    – Dave.
    Commented Jul 3, 2016 at 15:00

1 Answer 1


The battery will loose charge even if it has no loads connected. This happens due to the nature of the chemistry of lead acid type batteries. A fully charged battery will fully discharge in a few months. The older it is the faster it happens. Significant damage happens to a battery that is discharged while a charged battery has much less damage.

The optimum solution to batteries that are not used is to connect a battery maintainer and leave it connected whenever the battery in not in use for more that couple of weeks. These are available for less than half the price of a new battery.

When this solution is used it will not matter if the keep alive memory loads are left connected.

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