Mitsubishi Outlander Plug-in Hybrid Electric Vehicle Forum

I went on holiday for 3 weeks and parked with Meet & Greet at Manchester airport with 2/3rd drive battery 22 miles on it. Landed back yesterday and went to G&G counter to collect car. But they told me car shut down due to flat battery and still in yard. They have forecourt staff who jump start cars but will not touch PHEV. I had to call Mitsubishi First who sent recovery took 40 min. He came and we had to take him to massive yard 2 miles away. He did the jump start, but said be needs more training for PHEV and EVs. Apparently they have shut down mechanism for safety.??? Once started the drive battery was on 22mile as before when I left.
So why did the aux battery went flat? I will visit the dealer this week. The is only 2 months old car brand new.
Any one had such problem?

Left mine many times when on trips, longest was 7 weeks. Never had this problem.
When left for 7 weeks main battery dropped from approx indicated 75% to 50%.

Traction battery should top up other battery every day I think.

Annoying how they wouldn't just jump start it - the procedure for jump starting is in the manual. +ve lead to the tab in the fusebox under the bonnet (same as most cars with the 12V battery in the boot), -ve lead to the chassis.

Basically the 12V system is no different to most other cars, with the aux battery powering all the locks, lights, electronics, wipers etc. It has to be working in order to power the electronics for the drive battery to supply power as a result. It's charged whenever the car is in ready mode, or once a day when off if you have wifi enabled.

There have a been a few reports of 12V batteries going flat, it's not a very big battery anyway. But it should last a few months easily.

Just spoken to dealer. He said the car park guys move around the car in the yard and may have left sometime on. I found this explanation odd. He also said drive battery will only charge Aux battery when ON or driving or when plugged in. This is my second PHEV never happened before.
The recovery guy showed me how to do it and advised to buy 12v power bank if parking for long periods.

Seems to me that the AUX battery is topped up at 2 pm every day, regardless if it's connected to a charger or not.
The WLAN unit powers down if it's unused for a week or so.

https://www.youtube.com/watch?v=1yl5gaTPagE

The dealer is either incompetent or is bullshitting.

I have just realised I may have left the screen demister on , on timer at 7:20 am as I do in winter and was frosting every day. When reached home I reset all the timer and will observe now. A lesson learned about timers

That’s a very good point, assuming that power is taken from the 12V battery. I have mine set and it’d be easy to forget when routine is changed.
Something took the battery down and I’d be more interested in determining what that was (the cause) rather than how to perform a jump start.

I don't believe this was the problem.

The timer will force to engage the main lithium battery and even recharge the 12v lead acid battery ...this timer would have cost a huge reduction in EV range possibly even fully discharge the main battery (down to 20% SOC) over multiple days of demister (this consume around 4kw per 10min ... so almost 0.7kwh battery .. so a fully charged battery will go flat after 12 days.

I believe the dealer told you the real story: If the car park guy did not properly switch off the car (it could have left the car in the strange state that the traction battery is off, but 12v system in the car is on .. that happen when you switch on the car without pressing the brake pedal) .. the 12v battery will go flat in few hours .. and then the timer will not work anymore

Since your car still did had 22miles of EV range ... it is looking the timer never kick in : the 12V battery was dead already few hours after you left the car in the airport.

How old is the 12V battery? It may be dodgy, and the PHEV usage will mask that pretty well.

The 12V battery usage in a PHEV is very different to a normal ICE. In the latter, the battery provides a huge current to start the car, and you often notice if a battery is on its way out by a reluctance to start on colder days. Then the battery is overcharged by the ICE's alternator for the remainder of the journey. On the PHEV, the battery is only used to power up the computers, with the majority of its power then being provided by the DC:DC converter from the drive battery. Because it doesn't have to provide a huge load to start the car, a battery in a poor state may not be noticed, as the PHEV will do its best to compensate for any problems.