Fan noise while car is at home charging

[spinball]

I noticed a noise today while my i3 is in the garage charging. I've not noticed this before. It sounds like a low power air compressor, very similar (if not the same) as the noise I heard when the car is preconditioning using the AC.

Is this normal? What is it doing? My only guess is cooling the batteries but I don't know why it would only be doing this now and not all the other times I charged it. It's about 75 F here and the car has been parked for 4 hours now.

 

[jadnashuanh]

It could be the battery conditioning cooling things off. Whether that needs to happen could differ by how far you had driven previously before you charged it, and the ambient conditions. Driving warms them, and they may be managed while on the road some, if needed, but also they get warm while charging.

 

[psquare]

I noticed a noise today while my i3 is in the garage charging. I've not noticed this before. It sounds like a low power air compressor, very similar (if not the same) as the noise I heard when the car is preconditioning using the AC.

Is this normal? What is it doing? My only guess is cooling the batteries but I don't know why it would only be doing this now and not all the other times I charged it. It's about 75 F here and the car has been parked for 4 hours now.

Was it after you used the REx? I noticed on a warm day a couple of weeks ago that after brief REx use the fan was on for about a minute after switching it off.

 

[spinball]

Have not used the REx since delivery on June 6th.

I can see now why some were complaining you can't display the battery temp anywhere.the car is probably functioning normally but it's still nice to verify.

 

[TomMoloughney]

Yes it's normal. The fan is actually quite loud, unfortunately. I've noticed it runs while charging most of the time when the outside temp is around 80 degrees or higher. It usually doesn't run during the entire charging process, just the beginning.

 

[spinball]

Thanks Tom. I bet every single owner that has heard this noise while parked has at least wondered if there's a problem.

 

[alohart]

I wonder how much power the battery pack cooling system consumes. For those interested in minimizing electricity consumption, charging at a lower current that doesn't warm the battery pack enough to activate cooling might be the best approach if slower charging could be completed in a timely fashion.

 

[psquare]

I wonder how much power the battery pack cooling system consumes. For those interested in minimizing electricity consumption, charging at a lower current that doesn't warm the battery pack enough to activate cooling might be the best approach if slower charging could be completed in a timely fashion.

That's an interesting thought. Is there a benefit in switching the Settings to a slower charging mode?

Our overnight charging window is 7 hours long, plenty of time to charge the car even on a slower setting. Rarely is our i3 on lower than 30% SOC anyway. The only downside is that you have to remember to switch it to maximum charging speed when you're charging elsewhere.

 

[spinball]

From what was said above, the cooling should only come on at higher (80+ F) ambient temps. Where I am, that's probably only 3 months out of a year.

 

[alohart]

Is there a benefit in switching the Settings to a slower charging mode?

I have always assumed that there's a fixed charging overhead with the charger and DC-DC converter being on during charging such that slower charging would result in a bit more electricity usage compared with faster charging. However, the normal overhead is likely less than that with the A/C compressor, fan(s), etc., running when battery pack cooling is required. So there might be a sweet spot where charging is not quite fast enough to result in cooling but not so slow that normal charging overhead is significant.

Our overnight charging window is 7 hours long, plenty of time to charge the car even on a slower setting. Rarely is our i3 on lower than 30% SOC anyway. The only downside is that you have to remember to switch it to maximum charging speed when you're charging elsewhere.

I can change the maximum charging current on my JuiceBox EVSE in 1 amp increments, even while charging is occurring, so I don't have to muck with the i3's charging settings. But my 20 amp charging circuit limits my charging current to 16 amps which might not heat the battery pack enough to require cooling. I've never heard a cooling fan while charging even though the ambient temperature is typically in the high 70's in our apartment parking garage parking space. But we don't use our i3 during the hottest summer months, so battery pack cooling might occur then.

 

[jadnashuanh]

Ideal operating temp of the battery pack is 77-degrees F from what I've heard. A bit higher during charging may not be an issue. Most likely scenario is if you've just come back from a high speed run when it's hot out...the cooling may take place even prior to actually charging.

 

[KurtEndress]

I believe the KLE charging electronics also get warm. It's certainly part of the cooling loop. I wonder whether more power is lost and heat generated in the battery or the KLE. It's possible it is cooling the electronics rather than the battery itself, though that's a minor point.

 

[jadnashuanh]

Level 1 charging is less efficient than L2, since boosting 120vac to 380vdc is less efficient than 240vac to the same.

You'd have to instrument the vehicle to really know. Possible, but why?

 

[Lincsat]

I've noticed the charging noise (and preconditioning fan) are getting louder, now much louder than when new. Ambient is getting warmer here, not reached 80F yet though.