Tesla "Fire Crackling" Sound And B250e Battery Filter ?

[FordAnglia]

Greetings,

My work office has eight EV charger stations to service our fleet of 56 employee owned EVs. A very nice and popular perk! Most of the EVs are Tesla Model 3 vehicles, sadly only one B250e (mine)

One of the Tesla Model 3 owners posted the following to our internal EV forum:

Good morning all,
FYI for EV car owners: I have been experiencing some type of fire-cracking popping sound in the back of my driver seat. It’s happening on the way to work and home yesterday continuously every minute or two, and even I could hear the sound from the outside when all doors closed. Googling people mentioned about the popping sound or banging sound like metal expansion during super-charging, and I experimented it as well but this’s different type.
I am planning to call Tesla support to report the issue today.

Isn't that interesting! It turns out that Tesla issued a Service Bulletin in July 2019 to address this issue. The noise under the driver's seat is caused by blockage of the High Voltage Battery breather, which equalizes the air pressure inside the battery chamber and atmosphere.

Looks like our B250e annual Battery Check avoids this problem by replacing the Desiccant Filter, which can become blocked. The filter's other function is to remove atmospheric moisture from entering the high voltage battery chamber and causing corrosion.

Not sure if Tesla has an annual preventative maintenance program for this issue.

EV tech is fascinating.

Peter,

 

[JeffRay]

Peter,

Then there is the Air Dryer which was replaced during the B service. Service Advisor said it was related to the electrical system. Whatever.

 

[FordAnglia]

Then there is the Air Dryer which was replaced during the B service. Service Advisor said it was related to the electrical system. Whatever.

While watching the B250e factory video on YouTube I noticed a belt driving a pulley at the bottom end of the Drive Unit. Perhaps for an alternator to power and charge the 12V battery? Unlike the alternator in an ICE car, our EV motor only turns when the car is moving. For that reason an electronic DC-DC converter for 12V makes more sense, and that's what Tesla does. Now I'm curious about a rotating part driven by a belt in the B250e. Perhaps it circulates the battery and motor coolant?

I assume that other traditional ICE belts such as power steering, radiator fan, and A/C compressor, are driven by separate electric motors in an EV. ICE has the advantage of running when the car is not moving. Well, excluding the ICE cars that have Stop-Start operation to save fuel. I'm not a fan, and luckily rental cars I've driven have a Stop-Start disable switch.

Which brings us back to your Air Dryer service item. I wonder what it's role is in the EV world?

We had a counter theory on the "Fire Crackling" over lunch today. Could there really be an electrical problem in the Tesla heated seats or power seat motors? I'll share what my coworker finds out after a visit the Tesla repair shop.

Peter,