Car makes strange noises while in the garage

[ForumLeech]

My 2014 B250e makes noises in the front end of the car while it's in the garage with no key inserted. It starts with a strong click followed by the sound of liquid squirting through tubes and 45 seconds of continuous whirring noise like a small electric motor is running. I understand one of the triggers is a button, immediately left of the E/S button on the dash, for enabling climate control while the car is off and unattended. The button lights up blue or red. Turning off this button helped a lot but it still happens occasionally. Today I heard the noise after I disconnected the charger. A couple hours later it made the noise about a minute after I opened the driver door to release the hood. Does anybody know what all the triggers are for this noise and what is being accomplished? I am guessing it comes from a thermal management system used by the main lithium ion battery and climate control system but it doesn't seem necessary under all circumstances. Why would unplugging the charger cause the thermal management to come on? Also, I noticed the traditional 12V lead-acid battery under the hood shows 14.3V on a multimeter during the noise events and drops down to 12.3V when the car is silent. It's charging the 12V battery during the noise like a running gasoline vehicle would.

 

[JeffRay]

FL,

This is a new one. As I am not mechanically inclined, I can only offer the observation that I have never heard and that the coolant system for the batteries is the only liquid that would circulate. When you take it into the dealer next, have them check that function. If you are not getting any error messages, if a problem, it has not gotten serious enough to trigger a sensor.

 

[hallcp]

My B is parked outdoors, so I don't hear all the noises. But I do hear the system coming on and pumping fluids at the oddest times.

You might also want to peek at the two coolant reservoirs under the hood. If they're low I'd go to the dealer since I don't know what chemical should be poured in to top off. Plus, as a closed system it shouldn't be losing any.

But the noises may be quite normal.

Charles.

 

[ForumLeech]

My current hypothesis is the 12V battery is near the end of its life and is triggering top off charging from the main traction battery which then triggers its own thermal management system. The 12V battery is necessary for starting up the car and seems essential enough to trigger top offs. The car did complain about its 12V battery last Winter when it was left outside in freezing weather for a few hours. I plan to report my findings after I replace the battery.

Also, I understand the B250e uses a Tesla powertrain and main traction battery and maybe the larger Tesla community is familiar with the noises at odd hours. The B250e was a low volume car and we’re sort of in a bubble in our forum. It might make sense for us to be a subcategory of a Tesla forum. There’s a lot of DIY and tinkerer knowledge in the Tesla community.

 

[hallcp]

Yes, our Tesla also makes noises at odd times. In general it appears to be trying to pump coolant for the battery system, since it does not cool the interior by itself except in special circumstances. But I have heard it on both very hot and not so hot days, so go figure!

 

[Cardonman]

Strange noises...I’ve owned my ‘14 now for 3 years. Indeed the 12V accessory battery is used to provide power to the pumps. All the BMS is trying to do is keep the traction battery temp at its optimal temperature regardless if it’s hot or cold outside. (my guess 72-78F). I just got back from a three week trip and discovered that my 12V battery had dropped to 6.5V. The car was indeed plugged in to my Clipper Creek the entire time. So of course I found it very odd that the car was dead since the 12V was replaced last winter by MB. (The owners manual states that the car must be driven so that the 12V can be charged. Should not sit for more than two weeks.) I connected a trickle charger to the 12V and in about 2 hrs I got a “12V “ reading. Did a quick test drive and sure enough the 12V was back up to 14.3V. All those noises are normal. This car does use its 12V a LOT. Hence, the 12V battery life span could be less than 4 yrs. in my experience.

My $.02,
C

 

[ForumLeech]

Problem solved. I replaced the 12V lead acid battery under the hood and car stopped making noises in garage. Car is five years old and I kept that battery about one year too long. I believe the high voltage traction battery and its support systems were coming on to recharge the 12V battery every time it fell below a low-voltage threshold. And the 12V battery was so close to that threshold that small events like opening the door and triggering the interior light or just sitting for a few hours could trigger a recharge event.