12V Battery drains in 3 days

[user 258]

A bit of further investigation.

PHEV 12v Aux battery is rated at 36Ah.

A typical domestic WiFi router is rated at 6 watts.

That means it draws 1/2 amp, so IF I am right the aux 12v battery is flat in 72 hours, if not automatically charged.

Is there a clue here?

A domestic wifi router is a very different beast - it contains a lot more electronics than is necessary in the case of the Outlander wifi interface. The outlander wifi is just a simple wifi receiver and when it's not active, I would expect that it is programmed to wake up every 10 or 20 seconds to see if any device is trying to connect to it. That is just standard "Wake on LAN" functionality which I'm sure Mitsubishi are clever enough to implement. Coupled with low power microcontrollers and a low power real-time clock, it should be possible to get the average current drain down to a few tens of milliamps or lower. Obviously, when a device connects or a timed event occurs, then the whole system will wake up and current drain will increase.

I think you may be giving Mitsubishi more credit than they seem to deserve. They have got the car right, but there are many examples where little to no attention has been paid to the details. I would expect the wi-fi to consume a decent amount of power. Certainly not milliamps. Otherwise why make the car charge each day when not used?
Kind regards,
Mark

 

[ian4x4]

ian4x4 wrote:

A bit of further investigation.

PHEV 12v Aux battery is rated at 36Ah.

A typical domestic WiFi router is rated at 6 watts.

That means it draws 1/2 amp, so IF I am right the aux 12v battery is flat in 72 hours, if not automatically charged.

Is there a clue here?

Maby wrote
A domestic wifi router is a very different beast - it contains a lot more electronics than is necessary in the case of the Outlander wifi interface. The outlander wifi is just a simple wifi receiver and when it's not active, I would expect that it is programmed to wake up every 10 or 20 seconds to see if any device is trying to connect to it. That is just standard "Wake on LAN" functionality which I'm sure Mitsubishi are clever enough to implement. Coupled with low power microcontrollers and a low power real-time clock, it should be possible to get the average current drain down to a few tens of milliamps or lower. Obviously, when a device connects or a timed event occurs, then the whole system will wake up and current drain will increase.

Mark wrote
I think you may be giving Mitsubishi more credit than they seem to deserve. They have got the car right, but there are many examples where little to no attention has been paid to the details. I would expect the wi-fi to consume a decent amount of power. Certainly not milliamps. Otherwise why make the car charge each day when not used?

ian4x4 replied
If the 36Ah battery goes flat in 3 days, then I draw 2 conclusions.
The power drain from the various devices running when car 'powered off' and locked is about 6 watts.
The battery is not being automatically charged each day.
My experience (40yrs electronics and computing) suggests to me that this is more likely to be a software error than a hardware fault.
Yes, WiFi should only be polling, but it is a Tx/Rx device and there is nothing to stop it falsely responding to other devices (unsuccessfully).
But this is not the problem, unless the li-ion traction battery's charge is very low, then it should be charging daily.
Regards
Ian
PS Please how do you work the quotes function (I am old, that's my excuse)

 

[maby]

ian4x4 wrote:

...Ian
PS Please how do you work the quotes function (I am old, that's my excuse)

There is a button labelled quote at the bottom right of each message - click that and the text pane pops up prepopulated with the previous message wrapped in "quote" markers. The trouble on this board is that it will only permit three levels of quote nesting in a post and does not seem to have any automatic mechanism for controlling this, so in a deeply nested conversation like this, you have to hack the text that is pasted into the reply window...

 

[schlumbel]

We've been on vacation for 7 days with my wife's car. The PHEV has been left at home fully charged.
When we returned the car was beeping (constant, not very load, just like a kind of indication) .... seems it missed us ... kind a confusing for pedestrians passing by .... does anyone know the purpose for this beeping ?
Beeping stopped after opening the car. Display showed 43 kms range (typical after full charge is around 50).
Car worked normal.

 

[nlkruigerm]

Well; interesting that the big battery is supposed to charge the small battery every 12 hours or so. I do not think it does that in my car. Anyway, just back from a week holiday and no driving in the car and again flat battery (only 8V left). I will check with garage if the option to load the 12 V battery is working.
Hope this will solve it.
Just one question then: what happens is I stop the car 3 weeks or so and I have stopped with an empty big battery??? There will be no power to re-charge....
Marc

 

[maby]

Well; interesting that the big battery is supposed to charge the small battery every 12 hours or so. I do not think it does that in my car. Anyway, just back from a week holiday and no driving in the car and again flat battery (only 8V left). I will check with garage if the option to load the 12 V battery is working.
Hope this will solve it.
Just one question then: what happens is I stop the car 3 weeks or so and I have stopped with an empty big battery??? There will be no power to re-charge....
Marc

I think it would take a lot more than 3 weeks to have any noticeable impact on the traction battery - that is in the region of 10kwh - which at 12V comes to something over 800 amp-hours - enough to run the theft alarm and keyless entry systems for a fair bit more than 3 weeks. I would assume (hope?) that the designers were clever enough to set a floor on the depletion of the traction battery on the basis that it is far cheaper to replace a dead 12V battery.

 

[nlkruigerm]

Well, just got the car back again after some problem with the software, I kept on have the motor management light on.
This happened after the 12V battery was flat again after 3 days. (Only 10V left, not enough to get things going)
So, the problem of a drained 12V battery persists and garage also changed a relais of the towbar. Just measured this morning and guess what: still I'm loosing 0,5V over 12hrs, meaning still draining quickly. (Started at 12,6V now at 11,9V)
As far as I can measure the program to maintain the 12V battery by means of the drive battery does not work, all I can measure is a steady drop in voltage, no refreshment at all. I have the car not connected to the charge unit.
How should this program work and how can I check if this program is active in this car (program version maybe?)

 

[jaapv]

It is supposed to recharge once a day ( at 14.00 hours IIRC) and when the vehicle systems are active.

 

[nlkruigerm]

Thanks Jaap,

The problem then is, is does not run this cycle. (How to check???) I can just measure a steady decline in Volts.

For the moment I think I have fixed it by setting the timer for the airco (only window blowing) on a daily base. It looks like this will pump up the 12 V system again. I'm not sure how many cycles the car can handle with the drive battery low and not plugged in.... Let's see.
I read on some other pages that the cycle runs for 10 minutes, so if I do not use the car it switches off automatically (as you can only set the start time)
Still of course I would prefer to get the normal cycle going.