BMU Reset for 2018 Canadian PHEV. Alternate method idea

[jpleduc]

Here is the SOH chart for my battery before and after the BMU Reset in Mid October.

View attachment SOH PHEV 2018.jpg

Before BMU reset SOH was 35 AH
After the BMU reset it was 40 AH
As expected the SOH dropped regularly in the following days.

I drove 3700 km in 36 days since reset. This includes a 3 day trip of approx 850km /day. Most of these km are on highway at approx 100 Km/h. On these rides the drop rate was -0.1 Ah per 780 km or approx -0.1 Ah per day. This is probably normal as I used the ICE quite a bit in these trips.

SOH is now down to 38.4 Ah.

Still much better than before reset and I can do most of my daily commute on EV. I get easily 35+ km on EV per charge. I am currently in a much warmer area. When I return home with temperature below 0 C I expect to see drop in the mid 20.

Current SOH drop rate is -0.1 Ah /215 km.
at that rate my battery SOH will drop back to 35 Ah within a few months. But had I not done the reset it would be much lower.

So in conclusion the BMU reset alone has some benefits but it does not fix the fast degradation issue and it did not cause any adverse effects.

Next time I will try to get the dealer to do a proper reset.

 

[Smitsu2019]

Question do you turn off the vehicle after the aux battery is drained down then continue?

 

[jpleduc]

Question do you turn off the vehicle after the aux battery is drained down then continue?[/quote

I did not drain my battery to do the reset.

I tried that method but the EVSE never activated. I presume that the Aux Voltage was too low for the EVSE relays to turn on.

In lieu of draining the battery I installed a diode dropper which essentially lowers the AUX voltage to the desired voltage level. It is better for the AUX battery health and resolved the issue of not being able to activate the EVSE.

So here are the steps I followed

1) Turn on the vehicle (press start twice) without pressing the brake pedal

2) Drop the voltage until the alarms shows up
(I-E EV System Service Required)

3) Turn off the vehicle
==============

4) Connect the charger

5) Apply the 12 V back (for a short period) until EVSE activates
In my case I simply had to bypass/remove the diode dropper circuit.

6) Disconnect 12 V aux battery as soon as you hear the EVSE relay activation
(You will hear strong clunking noise)

At that point the BMU had reset.

I suggest that you talk to your dealer first. May be you can get them to perform a proper BMU reset. As long as Mitsubishi has not fixed the battery degradation problem they should do the BMU reset free of charge as soon as the vehicle SOH drops below 4 or 5 % per year of usage (ie if SOH is less than 96% after 1 year or sooner, 92% for 2 years etc). If I were to buy an outlander PHEV today I would demand that this be added in writing on the contract.

 

[Smitsu2019]

Thanks for the response. I'm down to 34.7 AH with less then 5000km. Is there a link on how to build the diode dropper an apply this method?

 

[jpleduc]

34.7 Ah is very low for 5000 km.
Mine was at 35 after 10 months with 11000 km. You lost 8.7 % of capacity. This is huge.

Is your vehicle a 2018? When did you get it? Did you get is new or used? Even then at 5000 km the battery SOH should never be that low.

I would bet it was already way below 38Ah when you got it. Check your battery age.

You should really go after your dealer to get it fixed under warranty. Don t waste anytime. Your situation does not look normal.


FYI When I started checking the SOH my vehicle had approx 4200 km and SOH was 36.5. Battery age was already 266 days old at that point. When I got the car on Dec 18 2018 the battery was already 201 days old. Had I known about the battery degradation issue I would have demanded that they do a BMU reset before taking delivery of the car and would have insisted on them commiting to do FREE BMU reset whenever the SOH gets below 4%.

Mistsubishi is not honest. They should never sell a vehicle as new when its battery capacity is not 100% of advertised capacity or at least very very close.

 

[Smitsu2019]

Brand new 2019 purchased Aug battery age shows 184 days old reported from watchdog.

 

[jpleduc]

I presume you have a North American car.
If so your battery should be a 38 Ah.

Are you sure your are checking SOH (State of Health) and not SOC (State of Charge).

SOC of 34.7 Ah could be right if charging did not fully charge de battery, SOC is almost lower than SOH at least in my case.

 

[Smitsu2019]

Yes this is a Canadian vehicle. Yes it's SOH here is a screenshot.

 

[DarrenHD]

Yes this is a Canadian vehicle. Yes it's SOH here is a screenshot.

Dude that is pretty bad. When I got my 2018 it had 37.1 Ah, and it quickly went down to 36.something. I got the MUT-III Se software, the driver, and the cable and now I can reset it myself anytime using the latest information on the procedures. I also did a DBCam and it came back at 37.4 Ah. Not too bad considering my 2018 sat on the dealer lot for 12 months and took 2 months to get to the dealer. So when I drove it off the lot, it was 14 months "old".

You will have to periodically do the procedures to reset the numbers if you want to keep the Ah up. The DBCam (if you can believe Mitsubishi's software) should come out with a fairly accurate SOH estimate. You can also do a cell smoothing procedure which can help too.

If you don't have the tools I would take it to your dealer and complain. Problem is, most dealers are probably uninformed/unaware (as are most purchasers) without the PHEVWatchDog...and be prepared for an argument with them. And if you are worried about voiding your warranty then you will have no choice to go to your dealer, or do the Dublin method (which should work on CDN models) and claim ignorance Remember there is no capacity warranty/guarantee on battery state of health in Canada, unlike some European countries and Australia.

For me I plan to squeeze every electron possible out of the (too small) battery, as I don't plan on keeping this vehicle for more than 4 years. I will just trade it in towards (probably) a full EV SUV at that time, so I don't really care too much.

 

[Smitsu2019]

Down to 34.1 now :twisted:

 

[wicked]

Question do you turn off the vehicle after the aux battery is drained down then continue?[/quote

I did not drain my battery to do the reset.

I tried that method but the EVSE never activated. I presume that the Aux Voltage was too low for the EVSE relays to turn on.

In lieu of draining the battery I installed a diode dropper which essentially lowers the AUX voltage to the desired voltage level. It is better for the AUX battery health and resolved the issue of not being able to activate the EVSE.

So here are the steps I followed

1) Turn on the vehicle (press start twice) without pressing the brake pedal

2) Drop the voltage until the alarms shows up
(I-E EV System Service Required)

3) Turn off the vehicle
==============

4) Connect the charger

5) Apply the 12 V back (for a short period) until EVSE activates
In my case I simply had to bypass/remove the diode dropper circuit.

6) Disconnect 12 V aux battery as soon as you hear the EVSE relay activation
(You will hear strong clunking noise)

At that point the BMU had reset.

I suggest that you talk to your dealer first. May be you can get them to perform a proper BMU reset. As long as Mitsubishi has not fixed the battery degradation problem they should do the BMU reset free of charge as soon as the vehicle SOH drops below 4 or 5 % per year of usage (ie if SOH is less than 96% after 1 year or sooner, 92% for 2 years etc). If I were to buy an outlander PHEV today I would demand that this be added in writing on the contract.

Hi JP,
Did you have to Turn on the vehicle (press start twice) without pressing the brake pedal even with your diode dropper to reset the BMU? Or you just add your diode between the Negative pole of your battery to reset the BMU? What king of diode and how many did you use?

Thx

 

[jpleduc]

Once the diode dropper circuit is installed and all switches are short circuiting the diodes so that the car sees the normal 12 V from the AUX battery, then you must turn on the car without pressing the brake pedal. Make sure that you do not have any accessories on (Fan, Heater, AC, Seat or Steering heater, lights, radio etc) in order not to exceed the current capacity of the diode dropper circuit.

 

[jpleduc]

I used 4 10a10 Silicon Rectifiers Rectifier Diode (Spec 10a 1000v R-6 10.0 Amp Silicon Rectifiers)
I bought the 10A10 online from Newegg.CA

and I also used 3 schottky diodes rated 0.3A, connected in parallel. Bought those from a local shop. Don t have the PN.

Bye

 

[jpleduc]

Schocttky are 3.0 Amp each Not 0.3 Amps as i Indicated in previous communication

JP

 

[wicked]

Schocttky are 3.0 Amp each Not 0.3 Amps as i Indicated in previous communication

JP

Thanks!

You put the 10a10 Silicon Rectifiers Rectifier Diode in series? You used 4 of them to drop the Voltage enough?

 

[jpleduc]

Here is a possible circuit.

I put several Ds diodes in parallel as they are only rated 3 Amps.View attachment Diode dropper circuit.jpg

 

[wicked]

Here is a possible circuit.

I put several Ds diodes in parallel as they are only rated 3 Amps.

Thanks alot!

 

[Smitsu2019]

Down to 33.3 now this seems to degrade very fast compared to other Mitsu PHEVs.

 

[Lon12]

I just did another reset using the same procedure I posted before but this time the drive battery was almost full and I did not run the 12v down.
So it only took a couple of minutes to do. Not sure why.
But this time it triggered engine light with P1AE6 error. Reset the fault code and it seems fine now.

 

[michael8554]

How did you reset the fault code?

(For me the yellow lettering in your signature is unreadable)