Odd value charge behavior

[jmueller065]

This is very strange, and I dread it may take a trip to the dealer...sigh.

For two days last week and this morning my FFE had some issues with value charging. Here is the setup:

• Very cold (<10F)
  Plugged into JuiceBox overnight set at 25amps or so (6kW)
  Value charge set to start at 1am
  Precondition set for 85F @ 6:30am
  Car partially charged up on "charge now" the night before and switched to "value charge" while charging (and less than full)

In the morning I get the notification from MFM that the car is fully charged except that:

• There is an odd 60Hz hum coming from the back of the car (unplugging the car stops the hum)
  The dash and MFM read 96% OR 97% full
  Precondition either skipped or car not at 85F

(The odd 60Hz hum is why I think I'll need to take it in ). It did this for two days last week and then returned to normal. All this week it has also behaved normally (this morning happened to be the coldest day of the week and the two days it did this last week were also the coldest days for the week).

Even with the car only showing 96/97% it still drives ok, regen works, etc. No dash faults whatsoever, no errors in MFM.

One speculation I have is that somehow the JuiceBox is acting flakey or that some salt has got in the charge connector somehow fooling the car to think its on a Level 1 instead of a Level 2 (thus making it do odd things). To test for this I'll switch over to my LCS-25p for the next few days and see if the behavior changes.

 

[davideos]

The 60Hz hum is the odd part because the charger (on-board) should be converting everything to DC. I wouldn't suspect the Juicebox since it just makes the 240V connection to the car active. Although I wouldn't dismiss it being able to cause an issue I would not suspect the LCS-25p to be any different.

I hear you on the dealer part. Not only do I not like the inconvenience, they don't always pay attention to details. When I had my battery work done, they also fixed a seal on the differential in the front. The foam cover under the hood used to have nice clips that hold the cover on. I found out yesterday that they replaced them with those generic plastic plugs used to hold interior parts together like headliners or plastic moldings.

When you hear the hum, is it actively charging? Or is it just connected. My only thought was perhaps the car can use AC to pre-condition as well as heat the battery in cold temps. I doubt it, but just a thought. In addition, the heater is in front, not the back. Did you put your ear to the rear battery pack?

 

[jmueller065]

When you hear the hum, is it actively charging? Or is it just connected. My only thought was perhaps the car can use AC to pre-condition as well as heat the battery in cold temps. I doubt it, but just a thought. In addition, the heater is in front, not the back. Did you put your ear to the rear battery pack?

It is the rear. You can easily tell just by walking around the car.

I don't think the car is charging: This occurs in the morning after it has value charged overnight (and after I've received the notification on my phone that the charge is complete). With the dash and phone saying 96% (less than 100%) my guess has been it is attempting to charge but somehow cannot (or that I've lost some battery capacity?), or that its in some goofy state and has been using the HVB to power the heater even though it is plugged in.

 

[WattsUp]

The foam cover under the hood used to have nice clips that hold the cover on. I found out yesterday that they replaced them with those generic plastic plugs used to hold interior parts together like headliners or plastic moldings.

Maybe, lacking much experience with the car, they broke the original clips when taking them off (and failed to tell you cuz, you know, they're so honest and up-front)?

 

[davideos]

Maybe, lacking much experience with the car, they broke the original clips when taking them off (and failed to tell you cuz, you know, they're so honest and up-front)?

I think they just assumed it would be a long time before I noticed or wouldn't care. But I think you are right about them breaking it...I think they likely lost one of them. I actually need to schedule an appointment because one of the rear seat belts doesn't latch. It looks like a manufacturing defect.

Anyway, on the humming issue, It wouldn't be a good think if the noise was coming from the battery, which could mean there was AC on it and some circuits got crossed somewhere...but unlikely if the battery actually gets charged. I wonder if the noise is actually coming from the charger...which I believe is mounted to the bottom of the car but more toward the front. Then, when the charging slows down at the last few percent, this function has failed and has resolved to make noise instead. Just be sure you can demonstrate it to the dealer. Their favorite phrase is "no defect found."

 

[jmueller065]

Anyway, on the humming issue, It wouldn't be a good think if the noise was coming from the battery, which could mean there was AC on it and some circuits got crossed somewhere...but unlikely if the battery actually gets charged. I wonder if the noise is actually coming from the charger...which I believe is mounted to the bottom of the car but more toward the front. Then, when the charging slows down at the last few percent, this function has failed and has resolved to make noise instead. Just be sure you can demonstrate it to the dealer. Their favorite phrase is "no defect found."

I think the charger is dead center in the "hump" where the exhaust pipe runs down the center of the ICE vehicle (in one of the plant videos they show the installation of the charger). Yeah in this video at 1:46 "High Voltage Charger Install":
https://www.youtube.com/watch?v=lQYKw6rdY7E

Update: I plugged the car into my LCS-25p when I got home with the car showing about 40% battery, and the outside temp was around 19F. The car started the low temp 15 minute charge immediately (that quick charge it does when its really cold and set to value charge). During this time it made the 60Hz noise but it properly charged the car (at least the battery % did increase by about 3-4%). At the end of the 15 minute charge it stopped charging and stopped making the noise. Thus the noise is associated with a slow trickle charge & heating the battery...hmm.

 

[Steve0512]

Okay I'm going to throw this out there. Is the sound a 60hz humm? or could it be the sound of a cold pump pumping cold fluid to condition the battery?

 

[jmueller065]

Okay I'm going to throw this out there. Is the sound a 60hz humm? or could it be the sound of a cold pump pumping cold fluid to condition the battery?

LOL now I hadn't thought of that (or pumping warm fluid) since it does sound a lot like 60 Hz--my EE bias showing. Now either the car is just starting to make this noise at 18k miles or I just haven't noticed the noise before.
That still wouldn't explain the car thinking it has a full charge and only showing 96% though.

 

[hybridbear]

What's a 60 Hertz hum?

 

[jmueller065]

60 Hertz is the A/C line frequency so whenever you've heard that buzz of an amplifier that isn't setup correctly; that is a 60Hz hum.
Wow, really you can find anything on youtube these days! 60Hz hum experiment LOL
https://www.youtube.com/watch?v=Vf6Bq-vStLA

I've been doing a few experiments to see where my 3-4% is going: (I don't remember seeing this drop last winter, even when I had the car parked outside and it would precondition to 85F on a <0F morning.)

• Charged up to 100%, no precondition and drive: % falls as expected (100, 99, 98, 97, etc.) (If I had a battery issue I would expect "unnatural" drops).
• When really cold out (<10F) either remote starting, or preconditioning uses 3-4% of the battery (even if its plugged in, regardless of which EVSE its using)
• In warmer weather there is no % loss on a remote start or precondition (warm being 20F or higher)
• GOM is still showing ~70 miles with HVAC off and ~50 with HVAC on--about normal

Aside from this small % drop on a precondition the car is otherwise fine.