[sarahbower1]

Finding info on the new Ioniq is very difficult, let alone any sort of diagnosing work, I could barely find good reviews on the car! What are you wanting to check through the OBD-II? Voltage or mAh? My question is even if you are able to connect to the car, how will you learn anything? Seems like it'd be necessary to have a before snapshot of the voltage or capacity, and then you could have a reference point to compare to?

I'm an engineer as well, so speak freely

I was hoping to see if there was significant volt drop across individual cells when they were put under load.

 

[brin]

It is not battery, as it would 100% catch fire in case of any bang. My guess is temperature difference due to long regen. You are heating a lot of parts there and some metal sheet or rod is compressing under heat and giving load bangs.

 

[kayan]

Ok, I did another test that might provide some relief and insight. I drove the exact same mountain road yesterday in pretty much the same conditions as before. The thing that I did differently this time was instead of doing a lot of regen on the way down the mountain, I mostly left it on lvl 0 (no regen). Of course, there was a little regen, but I made sure that the amount that I was using regen was significantly less than before.

The result is that even though I was using no regen (so hopefully no reason for the battery to overheat or something related to the battery), I still heard the bang from the rear! Moreover, I heard the bang happen at about the same location down the mtn that I did previously. From this, I conclude that:

1. The bang is not related to the battery regen, and likely not related to the battery at all, as I wasn't using regen nor propulsion since it was downhill so the battery did nothing.
2. Since the bang occurred at the same location as before, this makes me think that it is purely an elevation caused issue that happens once I descend a certain amount of elevation down the mtn.

These findings are some relief because hopefully they show that the most expensive replacement on the car isn't about to catch fire! However, someone with better power train knowledge will hopefully see these results and chime in to the possible components that could be affected by difference in pressure from elevation. I'm ruling out temperature for now because it's very hot here all the time and my car has seen both hot and cold temperatures and it has never caused this sound, so I'm singling out pressure change as the culprit for now.

 

[Jan Treur]

If you went downhill, I suppose you used the brake pedal. Therefore you still did regen, the difference is that this time you controlled it 'manually' by your foot.

 

[kayan]

That is right of course, but I tried to emphasize that while I recognize it's impossible to not regen at all, my point was that I regen'd significantly less than before by just letting the car coast faster instead of slowing it down.

Also, the amount of regen from using the brake pedal is much less than using only the paddle wheel controls because it also induces the disc-brakes when needed. As such, on my second trip, I regen'd only about half of what I did on the first trip.

 

[yticolev]

If you are holding a constant speed with either the brake pedal or holding speed via CC, regen will be identical. Physical brakes will require far brisker deceleration or the last few feet of a complete stop.

 

[sarahbower1]

Ok, I did another test that might provide some relief and insight. I drove the exact same mountain road yesterday in pretty much the same conditions as before. The thing that I did differently this time was instead of doing a lot of regen on the way down the mountain, I mostly left it on lvl 0 (no regen). Of course, there was a little regen, but I made sure that the amount that I was using regen was significantly less than before.

The result is that even though I was using no regen (so hopefully no reason for the battery to overheat or something related to the battery), I still heard the bang from the rear! Moreover, I heard the bang happen at about the same location down the mtn that I did previously. From this, I conclude that:

1. The bang is not related to the battery regen, and likely not related to the battery at all, as I wasn't using regen nor propulsion since it was downhill so the battery did nothing.
2. Since the bang occurred at the same location as before, this makes me think that it is purely an elevation caused issue that happens once I descend a certain amount of elevation down the mtn.

These findings are some relief because hopefully they show that the most expensive replacement on the car isn't about to catch fire! However, someone with better power train knowledge will hopefully see these results and chime in to the possible components that could be affected by difference in pressure from elevation. I'm ruling out temperature for now because it's very hot here all the time and my car has seen both hot and cold temperatures and it has never caused this sound, so I'm singling out pressure change as the culprit for now.

Thanks for doing that experiment.
A big reliefe for me too. I totally agree with you, it must be some sort of housing like the battery box that is conking in with pressure.

 

[sarahbower1]

Hmmm. There is a screen on the dash that tells you how much re-gen is been generated collectivly ( sort of ). Unfortunatly I don't do that trip often so won't be able to try it any time soon.

 

[emaijala]

Just an idea: if you switch to N before braking, regen is disabled. This of course means that the brakes will get hotter, so I'd avoid doing that for any longer period, but you could test also that around the location where the bang happens.

 

[DocMiller]

Sorry for being possibly flippant. It comes from virus lockdown as well child hood stress disorder.
After following this thread for awhile I keep wondering why everyone is missing the obvious answer.
3 BANGS scientifically and definitely proves it comes from Sonic Boom.

 

[kayan]

Just an idea: if you switch to N before braking, regen is disabled. This of course means that the brakes will get hotter, so I'd avoid doing that for any longer period, but you could test also that around the location where the bang happens.

Thanks for pointing this out.

 

[sarahbower1]

This is a good idea however I must confess that I am a little scared to try this out. I know there is some sort of reduction gearbox, I have no idear what exactly it does or how it will react to be put in neutral while moving. More importantly I would not like to try and put it back in Drive while the car is moving.

 

[brin]

Nothing to worry about. Neutral or drive are in this case just firmware options. Emotor is connected to wheels through reduction gearbox with fixed ratio (two simple tooth gears) and differential. There is no clutch, you cannot really disengage emotor from wheels. It is always turning when your car is moving. When you change to neutral, your invertor driving your motor is just freewheeling it. And when you set drive again, it just applies power or regen again.

 

[sarahbower1]

Thanks.