BMU Reset for 2018 Canadian PHEV. Alternate method idea

[jpleduc]

Tried Linquist, Dublin and D-Easy without any reset. Please let me know if you had success and if so what did you do

With Dublin method when voltage dropped around 8.0 volts several error came up however reset never occured.
Looks like that in Canadian cars the BMU has a better protection against power loss.

Here are my thoughts on why

In electronic circuit critical data is protected against corruption by Power Supply Circuitry that detects a power loss and
maintains a minimal voltage for a long enough period to save the critical data in a non volatile memory. Normally a small capacitor maintains this voltage.

I am wondering if we could Weaken this voltage somehow. If we drop the aux battery voltage around the 8.0 Volt level and maintain it at this level for a little while, the voltage on the NonVolatile memory capacitor will drop as well. So if we generate the power loss at this time, there would be less voltage available to save the data and possibly cause the data corruption forcing the BMU reset?

Please comment

JP

 

[Phevy]

I also have in vain tried the various methods to restore the SoH.
Interesting hypothesis, but without knowledge of the inner workings, it's mere speculation.
I don't want to damage my Aux battery, so cannot test this.
If on my next visit to the dealer nothing gets resolved, I might have to resort to buying the MUT s/w and adapter...

phevy.

 

[michael8554]

Lindqvist failed but D Method with diodes worked but not in the expected way.

See my post on page 5 of the D Method for stubborn cars thread

 

[Lon12]

I have a Canadian 2018 GT. Dublin worked for me.

 

[Phevy]

Great news!

Dublin worked for me.

What was the voltage you dropped down to?
What did you use for voltage source?

 

[MadTechNutter]

Tried Linquist, Dublin and D-Easy without any reset. Please let me know if you had success and if so what did you do

With Dublin method when voltage dropped around 8.0 volts several error came up however reset never occured.
Looks like that in Canadian cars the BMU has a better protection against power loss.

Here are my thoughts on why

In electronic circuit critical data is protected against corruption by Power Supply Circuitry that detects a power loss and
maintains a minimal voltage for a long enough period to save the critical data in a non volatile memory. Normally a small capacitor maintains this voltage.

I am wondering if we could Weaken this voltage somehow. If we drop the aux battery voltage around the 8.0 Volt level and maintain it at this level for a little while, the voltage on the NonVolatile memory capacitor will drop as well. So if we generate the power loss at this time, there would be less voltage available to save the data and possibly cause the data corruption forcing the BMU reset?

Please comment

JP

AFAIK all Mitsu PHEVs up to 2018 use the exact same battery management module but it seems that the installed firmware may be different.
So from a hardware perspective if the data can be corrupted/reset with a few seconds of low voltage there is no capacitor backup for volatile data involved at least not for the data that gets lost with these voltage drop methods. Capacitor backups usually hold power for hours and much longer.
It is more likely that this a bug in the hardware or firmware, who knows.

Your problem is that you do not know to what voltage level it has to drop and for how many seconds it has to stay that way.
8V seems incorrect. If you use a battery it could be over 10V and then it drops to a lower level under load while the charge is initiated.

I suggest get an old car battery, do NOT use your AUX battery and follow what worked for me:
http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=4581&start=0
or have a look at my diode dropper method if you are a little versed in electronics on page two of my thread:
http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=4581&start=10
and read exactly what michael8554 wrote.
Important that you use this between the negative pole of the battery and the released battery clamp as instructed while the charger is connected and try different diode and Schottky diode combinations, gradually reducing the voltage drop. Wait two minutes after charge has finally commenced and then check if the watchdog has updated to 38 Ah or more.

The actual reset might happen even before the charge starts, keep holding at least 20 seconds each time you reduce one diode. Keep in mind a Schottky diode drops a little less than 1/2 of a 10A10 diode, it is like 0.4V instead of 1V.
So if you buy 3x Schottky diodes and 4x 10A10 diodes, all that can handle 10A this should give you 0.4/0.8/1/1.2/1.4/1.8/2.2/2.4/2.8/3.3/3.4/3.8/4/4.2V drops, so quite a high resolution to find the exact spot.

I would start at 4.2V and and reduce each step above until the charger actually switches on.
Keep it connected for 20 seconds each time, even if the charge does not start.

 

[Lon12]

Great news!

Dublin worked for me.

What was the voltage you dropped down to?
What did you use for voltage source?

- Drove drive battery empty.
- Turned the car on but not in drive mode (start button twice without pressing brake).
- Turned on as many high load 12v accessories as I could. Fan, High beams, seat heat, portable 12v cabin heater. Took about 45 minutes.
- Watched Dog BMU voltage drop to around 7.2v with load. Unloaded returned to 8v.
- Disconnect 12v. Plugged in Mitsubishi supplied EVSE.
- Reconnected 12v but only till charger started. Had to do this three times to get timing correct.
- PHEV Watchdog immediately reported 40 Ah. Didn't have to wait.
GOM now says 62 km.

Used the onboard 12v battery.

 

[wicked]

Great news!

Dublin worked for me.

What was the voltage you dropped down to?
What did you use for voltage source?

- Drove drive battery empty.
- Turned the car on but not in drive mode (start button twice without pressing brake).
- Turned on as many high load 12v accessories as I could. Fan, High beams, seat heat, portable 12v cabin heater. Took about 45 minutes.
- Watched Dog BMU voltage drop to around 7.2v with load. Unloaded returned to 8v.
- Disconnect 12v. Plugged in Mitsubishi supplied EVSE.
- Reconnected 12v but only till charger started. Had to do this three times to get timing correct.
- PHEV Watchdog immediately reported 40 Ah. Didn't have to wait.
GOM now says 62 km.

Used the onboard 12v battery.

I can confirm that this method worked like a charm on my 2018 canadian PHEV
I had to try 2 last step 3-4 times to make it works.

Thanks alot Lon12 ! Went from 32.8Ah to 40.0Ah on my 20 000km PHEV

 

[jpleduc]

Currently working on an alternate method using a Diode dropper circuit, to bring the Voltage down without draining the PHEV 12V aux Battery.

The original idea came from Madtechnutter and was adapted and tested by Michael8554. I am awaiting parts to complete my circuit and will test it on a Canadian PHEV and will report back my results. Parts not expected till end of sept...

 

[KootenayLife]

Lon12

Did the guessometer start to drop range quickly or are you still getting great range?

 

[jpleduc]

I received the diodes and built the diode dropper. Unfortunately I was not successfui in resetting the BMU.

I inserted the diode dropper circuit between the aux battery negative pole and the car Negative terminal and followed
the processs (reduced the voltage to the bmu, once alarm came on I disconnected the 12V Battery then I connected EVSE and reconnected the 12 V Battery until the EVSE relays activated).

Tried several times without success.

I tried some variation on the voltage to no avail.

I noticed that the EVSE would not come on if the car has not been turned off once voltage is low. I also had to close the Rear door latch otherwise the car would not turn off properly and EVSE would not activate.

After reconnecting the 12 V battery and EVSE activated, I waited approx 10 to 20 sec before disconnecting the 12 V battery.

I will try again with 30 sec to 1 min.


Will keep you posted

 

[Lon12]

Lon12

Did the guessometer start to drop range quickly or are you still getting great range?

Yes. GOM has dropped at least 10 km now. I have not looked at the amp hour level yet. Still have about the same GOM range as when the car was new.

 

[michael8554]

What worked for me was:

Car switched off. Only rear hatch open wasn't a problem.

Start with 4 diodes.

Plug in charger

Wait for 1 clunk after about 23 secs, car doesn't start charging.

If no further clunks reconnect full 12v, start car, switch off and on again if you get an error message.

Check Watchdog. Watchdog didn't show that the reset had happened until I'd restored to normal as above.

If 4 diodes doesn't give you 1 clunk, try 3 diodes.

 

[jpleduc]

Thanks for the tip.

Will try next week and will report back here.

Have a great week end.

JP

 

[jpleduc]

I tried several variants of the Dublin & Diode dropper method and I can't get the BMU reset.
I know a few Canadian owners have been succesful with the Dublin or Diode dropper method but in my case it does not work,

I get the EV Failure alarm. Most of the time it disappears when I power the car up.

When I connect the Mitsubishi EVSE charger I quickly get the relay clunks then I wait a few second (tried different timing up to 1 min) before disconnecting the AUX batt. No luck it never resetted the BMU.

I tried with the brive battery, full, depleted (30%) and with 50% charge.

In a couple of cases the EV Failure alarm stayed on after I restarted the car. Then I turned the car off and turned it back on. Upon power up
the Alarm was gone. I fired up the Watchdog and it showed battery capacity was unchanged (no BMU reset).

So this seems to demontrate that I applied the Dublin-Diode Dropper method correctly but my car does not behave as expected. May be
some North American Outlanders 2018 have a different circuitry.

Any ideas what else I could try?
Are there other Canadian Users that are having similar problems.

JP

 

[michael8554]

If you wait a few seconds after the 4 clunk's you have waited too long, you must disconect 12v simultaneously with the charger starting.

If you are doing the Diode Method and are getting multiple clunk's then you haven't lowered the volts enough IMO.

 

[amason]

I tried a number of methods on an Australian model all to no avail...

Ended up buying a MUT3 device and software and managed to reset the battery that way.

So far have had a few 0.1Ah drops, but range has increased from 32 to at least 44Km

That may be the only way to go ??

 

[michael8554]

Even though I managed a Reset with the Diode Method I am buying a mini VCI and the MUT 3 software to do it properly and smooth as well.

 

[jpleduc]

Finally got the magic reset using the diode dropper circuit.

Thanks to Michael8554. He pointed out that the 12V aux battery must be disconnected as soon as the first relay clunk is heard.

Did that and got a Reset.

The dog shows capacity of 40 Ah while it was down to 35 just before the reset.

The diode dropper circuit method works.

Will see how this improves the car EV range.

Will keep U posted

JP

 

[Lon12]

"- Reconnected 12v but only till charger started. Had to do this three times to get timing correct."
I guess I wasn't clear. Reconnect and then disconnect is what I was trying to say.