flattening battery

[VladTepes]

Drove the wifes car fro 3 days while she was away and then went to start the Deefer... flat battery.

Managed to jump start it from a "spare" battery I had lying around (must get around to fitting that dual battery system eh).

Why would a battery go dead after just a few days of vehicle not being used ?

Once started, vehicle runs fine.

[abaddonxi]

Had this recently, battery was cactus.

[incisor]

what he said....

[drivesafe]

Hi Vlad, over the last month I’ve had a stack of people enquiring about their cranking battery going flat.

While there are a number of potential causes for flat cranking batteries, like not driving enough to charge the battery before leaving it for a few days between drives or not checking the fluid levels in the battery ( Flooded wet cell batteries only ) or leaving a door ajar which leave an interior light and the old favourite, emphasis on OLD, leaving headlights on.

Even with newer vehicle where the headlights are automatically turned off once the ignition is turned off, the park lights are still on.

BUT

At this time of year, it is usually an old battery on it’s last legs and the cold weather is just the last straw.

If you have a battery charger, try charging the battery and once fully charged, disconnect the negative terminal from the battery and leave it over night.

In the morning, you should have a voltage reading at least 12.75v at the battery terminals after you reconnect the neg terminal.

If it’s lower then 12.5v, your battery is no longer holding a charge.

Get your battery load tested but as abaddonxi posted, your battery is probably cactus.

[VladTepes]

Thank You.

Edit: P.S. I can;t blame the Traxide dual battery system as I haven;t fitted it yet (yeah I know)

Cheers mate

[drivesafe]

can;t blame the Traxide dual battery system as I haven;t fitted it yet

Probably good that you hadn’t.

In almost every occasion when a cranking battery fails, the first thing an auto electrician tries to blame is my dual battery controller.

let us know what you find.

[numpty]

Probably good that you hadn’t.

In almost every occasion when a cranking battery fails, the first thing an auto electrician tries to blame is my dual battery controller.

let us know what you find.

That's familiar.

On our Cape York trip one of our Defenders had battery problems and it was suggested that the Pirahna controller was probably at fault. Turned out to be a dud alternator.

[scarry]

Yep,as said by Drivesafe,we find with our fleet of work vans we have little or no battery trouble until the cold weather arrives.
They are on the road every day,& this also helps a half dead battery.If they aren't used for a few days,particularly in winter,the half dead battery will go flat ,as has happened to VladTepes.

If there are no faults with the vehicle,time for a newee