BMU Reset

[deanbarber1989]

Hi guys, apologies if this has been covered previously.

My car was in for its 6th service today (75k) and I had asked them to investigate the battery while the vehicle was with them because the latest data from the PHEV Watchdog app showed the battery SOH at 64.5% 25.8Ah.

When I collected my car they told me that they had carried out a 'PHEV BMU system reset' and that I should monitor it over the next couple of weeks. They also charged me an additional £89.95 for the investigation.

I have a couple of questions:

1. Should they have provided me with some further documentation to evidence the investigation and findings. For example the batteries SOH before and after the procedure?
2. As the SOH was less than 70% should the investigation and work carried out have been covered under the battery warranty? The car is 2016 and under 100k miles.
3. Slightly unrelated...….how do I run a new battery condition check on the PHEV Watchdog app? I can connect and start live data etc, but when I then go to 'Battery Condition' it just shows my old checks.

Thanks

 

[davep118]

Hi Dean,

Only had my 16MY since August 2020 so...

1. Don't know
2. It would appear to meet the criteria. See attached Warranty.
3. I "think" you only get a new battery condition report every time the SoH alters.

 

[Keefy]

I am in a similar situation and have just started the process.

I noticed on my 2017 PHEV that the SOC was about 68%. KM's are 75K.

I have been told on the Phone by the place where it is that my car is under warranty. The place I have taken it to seems quite clueless on EV's and I hope this is to my advantage and they just warranty the drive battery. 2nd best would be that they aren't as clueless as I thought and they do a BMU reset which I have read will re-allocate a lot of the capacity to free and your watchdog will confirm this after. I hope they don't charge as its a warranty fix.

Worst case scenario they say there is nothing wrong and charge me for the time spent lying to me.

I get the car back today so I will update.

Has anyone been able to get a warranty battery? What was the scenario?

 

[zzcoopej]

I noticed on my 2017 PHEV that the SOC was about 68%. KM's are 75K.

Has anyone been able to get a warranty battery? What was the scenario?

Be careful to use SOC and SOH correctly, you meant SOH (Health) above....

Yes, there are a group of about 20 of us in Australia who had their batteries replaced under warranty, and I know of one in Netherlands.
The group I was a part of in Australia was successful due to a website claim (since removed) when we purchased back in 2015 that the battery would not degrade more than 20% over the "life of the vehicle" (later clarified to be 10 years).

 

[Keefy]

OK So an update on my progress.

Sorry I do mean SOH not SOC. Thanks for picking that up.

I was referred by the original dealer to the main city one. They were very knowledgeable and knew what I was asking them to do. That is check the battery to see if it could be replaced or fixed free of charge as it was outside the conditions of the warranty.

The dealer called me about 5 hours after dropping off and said they had tested the battery, sent the data to Mitsubishi Australia and they had found that the traction battery's SOH was 29%. They then went on to say that this is normal for the age of the car and that there was no warranty issues.

I was pretty prepared for that answer and there was no charge for the test so no harm done. They were all very nice. However I knew that 29% was just a figure they picked as its less than the 30% stated on the warranty. I still have a lot of warranty to go.

On the same day I went and got a 2nd opinion. All they did was put a Mitsubishi approved ODBD reader on the car, found the BMU then printed out the page with the relevant information. In the print out its called "Battery current capacity" and showed 26.9 Ah. The Original capacity is 40 Ah.

Are these the kind of conditions that were met for other batteries to be replaced? Is there any similar website marketing claims related to the 2017 or do they have all that locked down now?

Thanks so much for any info anyone has.

 

[zzcoopej]

In the print out its called "Battery current capacity" and showed 26.9 Ah. The Original capacity is 40 Ah.

Sure the battery is 40Ah at the factory, however we use 38Ah to determine SOH as 40 is just unrealistic - Lithium batteries degrade rapidly at first and then level out.) http://evpositive.com/battery-history.html

Ok, 26.9 Ah / 38 Ah = 71% SOH, or 29% degradation. So I agree with both shops where you got your PHEV tested. No picking numbers out of the air, this is actually where your battery is at.

In Australia, for original owners of 2014 models (like mine) MMAL agreed to replace our traction battery due to a website claim implying no more than 20% degredation over the life of the PHEV ("life" was later clarified to be 10 years). More recent PHEV's are not being accepted for warranty replacement due to that original degradation claim being removed from the MMAL website. I don't agree with that, I think that once you make a statement on a website it lingers in the hearts and minds of purchasers and on forums etc. MMAL never posted that they retracted the claim, they simply deleted it hoping it would go away. All the above is documented in Andy's youTube channel eg - https://www.youtube.com/watch?v=PY-3AAEXxWE

 

[Keefy]

Yes I may have to re-watch those videos now that it seems to apply to my situation.

I will also redo my Maths for a 38 Ah start capacity.

So I have had a few emails back basically re-iteration what they have said previously. That is that they don't believe there is a fault and as such the battery does not qualify for a warranty claim.

Is there an Ah reading that would make the battery qualify? I can only charge the battery 6kWh so it the starting capacity was 13kWh Then the battery is only taking 50% of what it used to. Even if you estimate the inverter losses to remain the same as new its lost 50% of its capacity! Surely that is grounds for a replacement of?

Under Australian consumer law a product is meant to last as long as a reasonable person would expect the product to last. I think most people would expect their battery (or cars range) to be better than 1/2 as good after 4.5years?

 

[Keefy]

In the print out its called "Battery current capacity" and showed 26.9 Ah. The Original capacity is 40 Ah.

In Australia, for original owners of 2014 models (like mine) MMAL agreed to replace our traction battery due to a website claim implying no more than 20% degredation over the life of the PHEV ("life" was later clarified to be 10 years).

Does anyone have any copies of these websites? Maybe it can be found on the archiving websites?

 

[zzcoopej]

Does anyone have any copies of these websites? Maybe it can be found on the archiving websites?

Yep, email me via the Ev Positive "contact us" page www.EvPositive.com

 

[greendwarf]

I think most people would expect their battery (or cars range) to be better than 1/2 as good after 4.5years?

Now I don't have any means of measuring battery capacity or energy input, and frankly I don't really care - all I am interested in how far I can drive in EV on a full charge because it is just a means of transport. I an still getting just over 20 miles per charge after almost 7 years and 51k miles.

So if, as you suggest, you are down to only half the range after 4.5 years, then yours is not wearing as well as mine - unless, of course, you have done considerably more EV miles than me, as we know the battery life is limited by the number of recharge cycles.

 

[Ozziefletch74]

Hi Keefy.
I had exactly the same issue only to be given the run around did you get the problem sorted!
After they refused to budge I did a reset of the BMU and before hand the car wasn't to bad getting a range of 27klm after the reset I'm getting 40klm consistent, the battery was at 25.ah and the soh was 62 but I have never really bothered about the numbers more the fact that what I can get out of it and it seems to have worked all though it is dropping everyday with monitoring from the Dog app,when the range gets to low I guess I'll do it again and see how it goes but this far after 2 months of the reset it's going along nicely, mine is 2014 with 135000 on it so I am absolutely over the moon, the strange thing was with mine is that the lady I brought it off claimed she never charged it and only used it as a hybrid I would have thought that would have been much worse for the battery but as I said it's going along nicely city driving in ev mode

 

[ThudnBlundr]

So you fool the car into thinking the battery is better than it is, so it charges and uses the battery in a way that's likely to harm it. Every reset damages the battery even further. Why do you think they use the BMU to reduce the capacity over time? :roll:

 

[kpetrov]

At least when BMU reset is done it should be done properly followed by a DBCAM which completely discharge the battery and slowly charging it analyzing it's condition.

 

[B3333J]

For anyone interested in this, I wanted to see what happens when doing a reset without anything else following it.

My SOH was 29AH (76%) and followed up with a smoothing and DBCAM today. Not sure if this will slightly increase the SOH but I think it’s likely around 29/30AH anyways.

Anyway before doing this I thought I’d reset the battery when it was sitting at 100% SOC and run it down to 30% for the DBCAM procedure and just see what happened to the battery voltage. I’ve seen plenty of people talking about just doing a reset but no mention of what this increased range does to their battery voltage. It was reading 40AH SOH and 46km range on the dash.

Usually my car gets around 33-38km EV range depending on temp, traffic etc. it usually doesn’t drop below 3.7V before the engine kicks on, and the max voltage difference in this range (between max and min cells) tops out at 0.01V.

The below image is what happened beyond the normal range of my car when I reset my BMU. When I got home (the end of the graph) I had driven 46.7km, and the car still hadn’t started the engine. This reset allowed me to run my battery way below the normal voltage, probably not something I’ll be doing again outside of the DBCAM procedure.

I am wondering if it’s normal to get such a big cell voltage difference as you discharge the battery so low, does it mean I’ve got a few cells compromising my SOH, even though when average V > 3.7 the difference is minimal?

Hope this info is interesting to others, it answered a big question for me. Does a reset simply give you more range by dipping into the battery reserve, which likely decreases the battery lifespan? Yes, it seems it does.

https://freeimage.host/i/2254513d-ec6a-4e18-9e40-da331647c823.HENmMIn

 

[Daixiwen]

The voltage difference at the end of discharge is normal. Each cell has a slightly different capacity, and they are balanced at the end of charge. This means that it is at the end of discharge that you will see the highest difference in state of charge between the cells. In addition this is the area where the voltage will drop faster with declining state of charge, so you will see an even bigger voltage difference. It shouldn't have a big impact on your range because as you said in a normal usage the voltage will not go below 3.7V and the voltage difference between the cells is then very low.

 

[CharlieMac]

I there, just wondering how you get a dbcam, smoothing and BMU reset in Melbourne Australia? I've found the dealers here are the worst. They all lie about the SOH of my car's battery which is down to 20km on my 2017 Outlander.

 

[OncleV]

Hello there,

After reading about your experiences, I'm now hesitant to buy even a new car! The concept is appealing, but there are many negative testimonials regarding the battery warranty.

As a complete noob, I've just started learning about this wonderful car. Therefore, I would greatly appreciate your insights regarding the PHEV Watchdog readings of the car we saw over the weekend.

The car is a 2019 model with 61,000 kilometers or 37,900 miles on it. The live readings of the battery while charging were as follows:
- State of Health (SOH): 84.3%
- Ampere-hours (Ah): 38.8
(Refer to the attachment for more data.)

Initially, it seemed fine to me, but the battery "birthday" of 626 days raised some suspicions. I asked the owner if they had replaced the battery since 626 days doesn't equate to four years. They replied that they hadn't and expressed confusion about that reading. Interestingly, they claimed to be unaware of the existence of the PHEV Watchdog app

I presume that the battery reset was likely performed by the actual owner 626 days ago, I that the car dealer wouldn't have done such a thing, right?

Therefore, is it safe to conclude that buying this car, given the battery reset, is not a good idea?

Thank you in advance,
Cheers

 

[AndyInOz]

My instinct is that a battery reset, performed a year and a half ago, shouldn't be a cause for concern.

The software has had plenty of time to accurately reflect the battery's performance since.

A battery reset YESTERDAY would be a big red flag for me.

 

[OncleV]

I understand... But doesn't resetting the battery affect its long-term health?

I realize I need to do more research, and I will. However, I had to make a quick decision regarding this car.

Thank you for your prompt response!

Here's another question for the hive !

Under what battery percentage and over what mileage would you not buy a used car?

I'm specifically looking at 2019 or newer, 2.4L, Instyle models...

I assume that a 2020 model with the following specifications:
- Mileage: 103,500 km (64,300 miles)
- Current battery capacity: 78.5% of 43.7Ah
- Recharge cycles: 1,091
- Manufacture date: 1,371 days ago (without a battery reset)

...is not a car that you could keep for 10 more years, right?

I saw this car today, and for the first time, I had the opportunity to hear the engine running with the hood wide open (in battery save mode and while charging the battery). All I can say is that it sounded like my old diesel engine with a faulty piston joint. It sounded more like a tractor than a Japanese car for me... :?

The dealer assured us that this is normal, especially since the car had been stationary for about a month...

Is it normal for a Mitsubishi Outlander MY19 to make such noises?

Thanks in advance for your help!

 

[Lon12]

I just wanted to add that a BMU reset can happen accidentally.
I was working in the garage putting up shelving and had turned the car on to listen to the radio. After a few hours the radio stopped and I noticed the car 12 v had emptied.
My first thought was to plug in the charger. That didn't help. So I then jumped the 12v to try and get it charging. I'm don't remember the exact order I did this but afterwards my battery capacity was back to 100%.