Weird AC behaviour while fast charging

[pancello]

Hi!

Thank you for this great community you have! I've been reading this forum since looong before buying myself a lovely second-hand Peugeot iOn, and it sure made the difference choosing my first EV!

I'm posting here because, while being tremendously happy with my car, I noticed a weird behaviour while fast charging. When I plug in, if the battery is hot enough, it will turn the AC on to cool the batteries. But when it reaches about 50%, the AC turns off intermittently for a while, and then turns off completely. I even tried to restart the charge, and it doesn't start up again. The fan goes off, the AC light goes off...

Using caniOn I then notice the batteries start to heat too much, and still no AC.

I hear this is no usual behaviour, and the AC should stay until the end of the charge.

Any clue of what may be wrong (if it is wrong at all) with my AC?

I took some screenshots of caniOn during the latest fast charge. This is the first picture, where we can see the AC turning ON a few seconds after starting the fast charge.


Here we see the AC turning OFF. It will then start turning ON for like half a second, then OFF, then ON again, and so on until it stops completely (it happens so fast that caniOn doesn't even register it):


A picture of the cells's temperature after the AC turns OFF. Not very good looking, since they won't have any more cooling...

 

[JoeS]

pancello, welcome to the forum and thank you for your kind words. Thank you also for your descriptions and CaniOn screenshots.

The AC behavior you are experiencing is perplexing, but also quite common. Many of us have noted it, and do not understand why Mitsubishi would prematurely stop the battery cooling.

IIRC, there was some effort to remotely turn on the fan inside the battery pack but I couldn't find the posts and I don't believe it was successful. There is at least one thread discussing mods for redirecting the AC air directly into the battery pack - but, unfortunately, the AC could not be run while the car is charging.

 

[PV1]

Mine does it, too, but usually around 66-67%, although lately it's developed a habit of cycling on/off rather quickly at this threshold before shutting down completely. Confusing, but apparently normal operation.

 

[pancello]

Hi!

I bought the car with that AC hack which directs the AC to the pack instead of the feet. It is quite useful, but using it means less range...

So I now feel partly relieved and partly concerned... If it is normal behavior, at least it means nothing is damaged, and that's good! I just bought the car, and I wouldn't like to spend money fixing it already.

On the other hand, I fear that the pack will suffer very high temperatures during big trips, which could shorten its lifespan. So it stills concerns me... I try to keep it below 30°C, but it I fast charge it and then I need to use the full range (no AC), I believe the temperatures would rise even more...

Do you think this is worth a visit to Peugeot, anyway?

 

[pancello]

Also I noticed sometimes the car takes a while to start up... And as much as I know, it uses the 12V battery to start.

Could it be related? And the car just needs a new 12V battery?

Sorry for my ignorance... I'm probably talking nonsense, but anyway...

 

[JoeS]

...Do you think this is worth a visit to Peugeot, anyway?

Hi pancello, I personally am very reluctant to let anyone touch my i-MiEV unless absolutely necessary - your situation sounds 'normal'. In order for the service department to deal with your issue they would need access to a CHAdeMO charger - something I doubt they have. I would be fearful of their rummaging about, as there are probably very few technicians out there with i-MiEV/iOn/C-Zero experience. Will you be making many seriously-long hot summer trips whereby this would be a concern?

Regarding the start-up time delay, it should pop into READY within about a second of turning the key to the START position, although some have noted a hiccup if they rush through that. In your shoes I would take my time and note the car's response until you're comfortable and can consistently activate the car. A low 12v battery would manifest itself with any number of different strange reactions - you might simply measure its voltage after the car has been sitting overnight to see if it's ok.

BTW, you might wish to update your location as we have forum members from all over the world.
http://myimiev.com/forum/viewtopic.php?f=13&t=3196

 

[pancello]

...Do you think this is worth a visit to Peugeot, anyway?

Hi pancello, I personally am very reluctant to let anyone touch my i-MiEV unless absolutely necessary - your situation sounds 'normal'. In order for the service department to deal with your issue they would need access to a CHAdeMO charger - something I doubt they have. I would be fearful of their rummaging about, as there are probably very few technicians out there with i-MiEV/iOn/C-Zero experience. Will you be making many seriously-long hot summer trips whereby this would be a concern?

Regarding the start-up time delay, it should pop into READY within about a second of turning the key to the START position, although some have noted a hiccup if they rush through that. In your shoes I would take my time and note the car's response until you're comfortable and can consistently activate the car. A low 12v battery would manifest itself with any number of different strange reactions - you might simply measure its voltage after the car has been sitting overnight to see if it's ok.

BTW, you might wish to update your location as we have forum members from all over the world.
http://myimiev.com/forum/viewtopic.php?f=13&t=3196

Hi Jos! Thank you for your help

I don't know what is a seriously-long trip, but I'll be making some 5-6 fast-charge stops in a trip during this summer, and I expect about 30-40°C outside... I don't know either if four or five days per year with cells above 40°C is something I should worry about in terms of battery durability (providing I can stay below 33°C the rest of the year)?

About the start up of the car, I think what happens is what you describe: I rush too much and the cat doesn't like it! So I should probably discard problems with the 12v battery... I'll try to measure the voltage anyway just to be sure.

I'm from Portugal! A small country in Europe I'll update my location

 

[JoeS]

...I'm from Portugal! A small country in Europe I'll update my location

pancello, we have another member from Portugal (Tábua), who goes by the name Malm, who has probably used/abused his battery more than anyone else on this forum. You might scan through his posts (he has many) and perhaps contact him? After all, you are only 140km from each other.

 

[pancello]

...I'm from Portugal! A small country in Europe I'll update my location

pancello, we have another member from Portugal (Tábua), who goes by the name Malm, who has probably used/abused his battery more than anyone else on this forum. You might scan through his posts (he has many) and perhaps contact him? After all, you are only 140km from each other.

Sure I "know" him from a Portuguese EV forum. He's the absolute hero! I'm happy to know that he is known here as well.

I'm still on the process of reading his "diary" on that forum, which has more than 200 pages! I learnt so much reading it that I will never be able to thank him enough.

I'll probably contact him I work near his town also

 

[Aerowhatt]

I have seen the same behavior from the AC during DCQC. From watching individual cell temps on Canion I think it has to do with the disparity between cooler and warmer cells. As we know the cell cooling is far from uniform in the pack. Seems that my AC shuts down when the difference between the warmest and coolest cell censor is about 18F. This does make some sense from a battery balance and longevity standpoint.

Nothing definitive just an observation . Perhaps other interested parties can watch theirs from the same perspective and see if it holds water??

Aerowhatt

 

[pancello]

That's interesting... The screenshots I took and posted above also indicate 7°C difference. Next time I use a DCQC I'll take some screenshots as well, or maybe even record the screen.

What I don't understand is why you say that from a longevity standpoint the pack should not have great differences between cells? I thought that although my battle should be against the warmer cells, having some very cold ones could only mean good...

 

[rnlcarlov]

I've had up to 12ºC diference in cell temperature. I had some cells near 42ºC and others at 20ºC. My A/C never stopped during AC, so it could be something more specific to the newer models (since both my C-zero and Malm's imiev are 2011 model year.)

 

[pancello]

It could be that the 14.5kwh battery models have this stop during charge. But I'm pretty confident my model is 16kwh... Is there anyway I can confirm which model is mine?

 

[rnlcarlov]

It could be that the 14.5kwh battery models have this stop during charge. But I'm pretty confident my model is 16kwh... Is there anyway I can confirm which model is mine?

It's pretty easy. Just get Canion or EvBatMon running and check the pack voltage. The 14.5kwh have less cells so the voltage is around 300-320V (depending on SOC), which is lower than in 16kwh models (320-360V).

 

[Aerowhatt]

I've had up to 12ºC diference in cell temperature. I had some cells near 42ºC and others at 20ºC. My A/C never stopped during AC, so it could be something more specific to the newer models (since both my C-zero and Malm's imiev are 2011 model year.)

We do know that they have changed the firmware along the way. Even updated some older models. There are even a few minor differences between mine and my wife's. They are the same model year built less than 60 days apart from each other!

Aerowhatt

 

[Aerowhatt]

That's interesting... The screenshots I took and posted above also indicate 7°C difference. Next time I use a DCQC I'll take some screenshots as well, or maybe even record the screen.

What I don't understand is why you say that from a longevity standpoint the pack should not have great differences between cells? I thought that although my battle should be against the warmer cells, having some very cold ones could only mean good...

Since all the cells are seeing the same amperage and they behave and age differently based on temperature during fast charging. It does make some sense. I agree with you that fighting the warmest cells would make more sense. However since their warranty covers cell failures but not degradation. They are more motivated to keep the cells in the same thermal range during extreme events like fast charging. Less worried about overall degradation than developing cell disparities.

Having flown electric RC sport planes for years. I found that batteries charged at the field (at 2C rate) on ice lasted significantly longer than those at ambient temps. The Ice charging would cool the outer cells well but the center ones would still be hot. Batteries that were allowed to cool and equalize the cell temperatures before fast charging lasted far better than the other scenarios allowed for. All based on cycle life, not calendar life.

Aerowhatt

 

[pancello]

Hi!

I just got canion back, and checked both temperatures during DC charging and volts. It seems my pack is really 16kwh, since they remain above 320V. So it really should have something to do with firmware updates and not the batteries versions...

About the temperatures, couldn't yet find anything conclusive since I didn't do a lot of DC charging, but it seems the AC comes off at 55%-56% no matter what. But at that point, the difference between cells is almost always above 6°C too. So... I think I have to do some more charges before getting a definite answer...

Thank you aerowhatt and rnlcarlov!