12v battery death

Mitsubishi Outlander PHEV Forum

Help Support Mitsubishi Outlander PHEV Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

nalinasanka

New member
Joined
Aug 21, 2021
Messages
1
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
 
nalinasanka said:
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.
 
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.
 
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.
 
greendwarf said:
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
 
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.
 
During a cold snap a few weeks back I ried to start the car (2017 4hs) and it wouldn't play, just kept scrolling through all the alarms. Got it to start eventually and took it to the dealer, they tested the 12v battery and said that it was only holding a 75% charge. They said that it needed a 24 hour special charge. They did this and then informed me that it hadn't worked as well as they hoped and it would need a different kind of charge taking a few hours. This done they returned the car and said that the battery was now good. For this service they charged me nothing even though the 12v battery has only a two year warranty.
 
There has been a recall for replacement 12V batteries from Mitsubishi Motors Australia Limited (MMAL).

I replaced mine myself ensuring that the breather hose is firmly connected and the battery is firmly mounted.

At the end of the the letter it states that I have the option to purchase a 'genuine' factory battery if it was not supplied by MMAL.
I smell a bit of a scam here as the MMAL supplied battery is 2-3x more expensive that the one I got from Battery World, that is otherwise same brand and identical in size and features, only I had to attach a slightly different connector for the breather hose.
 
My Outlander PHEV is 2018, I think it was built about July. It was a dealer demo in NZ and was 8months old when I bought it, with under 400km on the odometer.

Recently during regular servicing (October 2022) the 12volt battery was tested and was found to be Good. I don't know why they tested it, probably my stated concern about Drive battery SoH was lost in translation, whatever.

Last week after going to and from work, plus to and from super market, totalling less than 20km after a full charge, I went outside about 8pm to check I had locked the car although I had plugged in as I use timed charging from 9pm to midnight (because it's free). I could not lock the car, It was totally dead. 12 Volt battery was down to 2 volts. No doors were open so no interior lights on and it is set to shut off accessory circuit after 30 minutes. Headlights are always set to Auto. Even if I left it in Ready state the DC-DC converter should have maintained the 12 volt system.
Timed climate control was not on, I had used it a couple of times the week before to cool the car when I finished work but I had turned the timers off.
So I have no idea what caused the battery to run down. I tried using a battery charger, but being a "Smart" charger, it refused to start because the battery was too dead. Not so fxcjing smart after all really. The only way to recover was a Jump start with another battery. The car immediately powered up with lights on just as it does when unlocking it in the dark. And it started charging the 12v battery. I could see 14V at the jumpstart terminal in the fuse box. Also It was charging the drive battery as I probably cancelled the timer with remote fob. For some reason I went to check the battery itself but to my horror It was HOT and the grounding cable was also hot or at least Very Warm. That suggests a lot of current from the converter. I immediately shut down everything and removed the battery. I put it on a 25amp (other smart) charger but it's leads were getting too warm for comfort. (I will say those leads are actually inadequate for that current)

The whole episode freaked me out big time. I have no idea why it happened and no idea why the converter was so agressive. I had to run with the non fitting other battery for a day and get the original one tested, which again came out as good, with better CCA figure than it's stated rating.

I have rechecked/reset all settings and so far everything is normal.

Any one got any ideas on this?
 
Check to make sure that heating/cooling isn't being turned on by a timer setting.

When I first received my car, it was auto-heating twice per day because of timer settings.
 
To nrayanov.
Well you can set charge timer by wifi and the smartphone app, but it will also appear in the charge timer settings on the car screen so not really any difference.

It was about an hour awat from start time but with the 12volt Auxilliary battery dead, nothing was going to happen.

To AndyInOz,
climate timers had been used a few day the previous week but were cancelled.

Update, Yesterday after not using the car and not being plugged in for a coouple of days, I went to use it and it unlocked ok, but that's as far it went. Interior lamps were dim, but the car would not "start". I did get Accessory on but then could not turn off and warnings started to appear in the display.

Eventually used a Lithium jumpstarter/powerbank to kick it into life and then of course it begins charging the 12volt battery. Further checks show it is not fully charged. I think it is self discharging and at end of life. Date code is 1822 so its aboout 4y9m old and due for recycling.
 
This explanation makes some sense as to why these fail
https://youtu.be/pu30bchGu50

I'm thinking I will add a ctek comfort connector on the battery and hook it up every few months to let it hit the battery with a desulf and charge cycle. How much different it'll make I don't know, but the battery on my old Alfa was 6 years old when I exchanged it earlier this year for the PHEV, that was regularly on the ctek charger as it has an annoying power drain that I never did find.

I've not checked the float volts on the battery with the system running but if the battery isn't supplying much load are we seeing a similar situation as with UPS backup systems? They often kill the batteries in 3 years or so because they float the battery at too high a voltage. The APC SmartUPS's I have did that so I adjusted the volts down to a little below the battery maker's spec (so more like 90-95% charged, say) and now 5 years on they are still reporting good health and have handled a number of power outages of 45mins to 2+ hours. Of course how we might adjust the float voltage on the DC-DC converter is another matter if that turns out to be too high...
 
My limited understanding of this kind of thing is...

Lead acid batteries need to be kept at at least 50% charge.
(deep cycle batteries can be discharged to 80%)

Any time the battery falls below that charge, permanent damage is done to the battery.

So, during a battery's lifetime, it only takes one mistake to greatly reduce the battery's performance.

Examples given here have included putting the car into accessory mode and leaving the radio on.

If a battery has been discharged below 50% once, it is very likely to happen again, because the battery's capability has been diminished.

My experience with other cars, has been that one episode of 'flat battery' usually means that I have to replace the battery within a year.

So far, my original 12V battery in my car is showing no signs of failure.

NB. The recall for 12V battery in Australia was because some dealers had been fitting batteries that were not AGM batteries, these are significantly cheaper, but too dangerous to be fitted in a vehicle's interior.
 
hi nalinasanka

I have same issue here with my 2014 PHEV Outlander in France . Mitsubishi local garage changed the battery then the ECU after long tests and diagnostics, the car is still having same problem , the 12V battery depletes after 3 or 4 days, and the car still stay in Mistubishi garage for last couple of months. The issue is now escalated at Mistubishi Europe .
Did you find the cause of this issue and did you solve it since then?
Thanks very mush for your response
Greetings from Paris
Emmanuel
 
EmmanuelF said:
hi nalinasanka

I have same issue here with my 2014 PHEV Outlander in France . Mitsubishi local garage changed the battery then the ECU after long tests and diagnostics, the car is still having same problem , the 12V battery depletes after 3 or 4 days, and the car still stay in Mistubishi garage for last couple of months. The issue is now escalated at Mistubishi Europe .
Did you find the cause of this issue and did you solve it since then?
Thanks very mush for your response
Greetings from Paris
Emmanuel

Hi Emmanuel,

Any more details?
I have same problem and local Mitsubishi dealer cannot find answer. Measured drainage only 0.014Amps but someday after a short term the 12volt drops under 10volts.
12volt battery is new and they also measured that one, that is not problem.
 
Back
Top