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12v battery death

Posted: Sat Aug 21, 2021 9:07 pm
by nalinasanka
I have outlander 2014, If I parked 1.5 - 2 days my 12v battery goes down around 4v . vehicle cant start, I had to jump start, first i think its 12v battery problem, but I replace new battery also. same fault happens. when i jump start and drive little distance around 5km , battery will fully charge. and i can start around 1.5-2 days without jump start. my drive battery also in good condition. several technicians including Mitsubishi motors checked, but nobody found any fault. please comment me do you have any idea?
Thank you

Re: 12v battery death

Posted: Sun Aug 22, 2021 7:20 pm
by zzcoopej
nalinasanka wrote:
Sat Aug 21, 2021 9:07 pm
I replace new battery also. same fault happens
You don't have a dashcam or other accessory hardwired to the 12V ? If nothing changed, then there is definitely something draining the 12V when the car is parked. Check interior lights are switching off when the doors close, and if you have a voltmeter that measures current, disconnect the 12V and measure the current draw by connecting the meter in series, any auto electrician can do this if you don't have a friend with a voltmeter. Once you have established there is definitely a large current flowing (a small current flowing is normal, especially if you have the Aspire Wifi model PHEV) you can pull fuses one by one to establish which circuit is causing the issue.

Re: 12v battery death

Posted: Mon Aug 23, 2021 12:23 am
by MadTechNutter
Also check the sunshade mirror light, should go off automatically but you only know if you check.

Installing a dashcam can be a real PITA with this car.
In my case the dashcam switches off after 20 minutes after I park and it it detects no motion.
But the step down converter from 12v to 5V (USB plug to camera) still drains a tiny 6mA standby current.
The overly sensitive detection circuit in this car keeps the 12v AUX power for the indoor lights and what ever else active, which drains almost a whole amp from the battery despite nothing else on. 30-40 hours later the AUX battery is dead.
I consider this a design flaw.

I found an active 12v in the unused(in my case) lane departure warning box behind the rearview mirror, pink wire. I tapped that for my dash cam and the 12V AUX power stays off. The 6mA is nothing for the AUX battery, self discharge is higher.

Re: 12v battery death

Posted: Tue Aug 24, 2021 4:01 am
by greendwarf
OP reports low battery after 1.5 to 2 days - so must be base model without Wi-Fi (Gx3h or equivalent), otherwise it would be topped up from the drive battery each day.

Re: 12v battery death

Posted: Fri Sep 10, 2021 3:59 pm
by Brendonm
greendwarf wrote:
Tue Aug 24, 2021 4:01 am
OP reports low battery after 1.5 to 2 days - so must be base model without Wi-Fi (Gx3h or equivalent), otherwise it would be topped up from the drive battery each day.
That feature can be disabled, (can't remember how, through the head unit perhaps?) possibly it has been disabled and that's the cause of the battery drain

Re: 12v battery death

Posted: Sat Sep 11, 2021 9:06 am
by mellobob
Has anyone figured out the logic between charging a battery and presence (or lack) of having wifi in a car?

Re: 12v battery death

Posted: Sat Sep 11, 2021 3:58 pm
by AndyInOz
Yes, the wifi module is a constant drain on the 12v battery which means that the battery needs to be recharged daily, even though the wifi module turns off after three days of no use.

Cars that don't have the wifi module don't have this continuous drain on the battery, unless something has failed, or an after-market accessory has been added.

Re: 12v battery death

Posted: Sat Sep 11, 2021 6:43 pm
by mellobob
Okay, makes sense. Still, if you've got a so-so 12v battery and lots of energy in the drive battery it'd be nice to have the car do a regular top up :)