Flat Battery.

[KezR33]

Hey guys,

Jumped in my car yesterday to find a dead battery, after jump starting it and driving it around for a bit, I get in again today and once again its flat. I don't think the battery is that old, and its quite large so I don't think it needs replacing (anyway to test this?).

Ever since DECA my head unit has been playing up somewhat, I suspect this may be the cause of power loss. Any idea what could be draining the power, or is it more than likely in need of replacement?

Appreciate any support.

[conan7772]

Hey guys,

Jumped in my car yesterday to find a dead battery, after jump starting it and driving it around for a bit, I get in again today and once again its flat. I don't think the battery is that old, and its quite large so I don't think it needs replacing (anyway to test this?).

Ever since DECA my head unit has been playing up somewhat, I suspect this may be the cause of power loss. Any idea what could be draining the power, or is it more than likely in need of replacement?

Appreciate any support.

An auto electrician will have a battery tester.

The cold weather may have killed it.

Usually is stereos and alarms that cause current drain.

Put a meter on each fuse one by one if you want to have a go yourself.

[R32oNate]

It might be that your alternator is gone. Check your battery with a voltage meter when the car is on. It should read between 13-14v otherwise check your alternator. Hope that helps!

[Munkyb0y]

you can check the drain on your battery by doing the following:

- car off (turn alarm siren off, or it will start squealing when you remove battery leads)

- remove earth cable from battery

- grab your multimeter, and set it to read amps (10A or higher)

- connect one probe of the meter to the earth cable, and the other probe to the negative terminal of your battery

- now you will see an amp reading, indicating the current being drawn while your car is switched off.

- a current draw of 50mA or less (0.05A) is considered normal. anything near or over 1A is too high, and means something is drawing current that shouldnt be.

My battery has recently gone flat (along with 4 others of ppl i know - yeah weird!!) my test came back at 0.02A, which means no excess current drain.

[jiffo]

I wonder what the battery life is for the siren's power supply?

Maybe it's just sucking the juice little by little?

Won't show up in the previous poster's test, as he mentioned, you have to isolate the bloody thing.

[Munkyb0y]

i dont think it needs power until the battery is disconnected, at which time, it begins to make noise. ie, its a back up battery.

another thing i did when testing was to switch the alarm on, but make sure the bonnet pin, boot light, etc would not trigger it. it made no real difference to my reading.

Edited September 21, 2010 by Munkyb0y

[KezR33]

Cheers guys, got tomorrow off so I'll have a look then.