Battery coolant heater broken

[20alawrence]

Hello, I had just replaced my battery heater on my 2015 model s 85D, however after the installation, the battery heater still does not pull any power, and when plugged in with a cold battery all I’m pulling is 1/30 A, I have no warnings or messages on the dash either.

 

[Gtech]

Do you also checked service mode for hidden errors?

 

[20alawrence]

Do you also checked service mode for hidden errors?

I just checked, nothing there either besides a parking sensor error, very strange, thank you for mentioning that though! Never hurts to take a look

 

[howardc64]

Tesla algorithm is really lazy at triggering the battery heater. Had a friend that was also chasing what he thought was a non working heater. Turns out its by design.

cell warm up analysis

Sorting out coolant heater behavior with a fellow 2013 MS owner with gen1 DCDC in these winter months. Used scanmytesla to record 3 trips. Here is the conclusion and data Car is no hurry to warm up the cell. Regen is limited for quite while until avg cell temp reach ~18.4C which takes more than...

teslamotorsclub.com

Looks like max defrost is the more urgent trigger. If just driving around, car will just assume to slowly use stator heat.

 

[di kou]

Any update? I am having the same issue here.

 

[di kou]

Hello, I had just replaced my battery heater on my 2015 model s 85D, however after the installation, the battery heater still does not pull any power, and when plugged in with a cold battery all I’m pulling is 1/30 A, I have no warnings or messages on the dash either.

I have sometimes in warm Weather around 20-25 *c. The car shown The battery is heating and charge rate dropped from.30/30 amp to 1/30 amp. Any update for you problem?

 

[20alawrence]

Still no fix yet, hopefully this winter I can figure something out, otherwise I may just put a regular coolant heater with a plug in the car so I can at least plug it in to my wall to warm the coolant and battery before I leave.

 

[OrbiterTI4]

When I set my navigation destination as a Supercharger that's near enough to prompt the "preparing battery for arrival" message, I'm guessing that is turning on the battery heater, but I don't have access to data that @howardc64 has to confirm.

 

[Zuikkis]

Still no fix yet, hopefully this winter I can figure something out, otherwise I may just put a regular coolant heater with a plug in the car so I can at least plug it in to my wall to warm the coolant and battery before I leave.

Hmm. Cold battery is only an issue while charging. There's no need to preheat before driving.

I assume you car is working as intended..

 

[Zuikkis]

Hello, I had just replaced my battery heater on my 2015 model s 85D, however after the installation, the battery heater still does not pull any power, and when plugged in with a cold battery all I’m pulling is 1/30 A, I have no warnings or messages on the dash either.

Just noticed this bit in the first post.

I'm from Finland so I often charge at cold temperatures. Usually the charging starts like you say, at 1Amps. It can be like that for quite long, 30 minutes or sometimes even over an hour. After that it starts ramping up the amps, quickly reaching the maximum.

I'm pretty sure it IS running the battery heater when it shows 1A. However the heater is not run from mains, the power is taken from the battery. This sounds stupid at first, but it actually makes sense. Drawing power from the battery will actually heat it. So the heater is double effective; it heats by drawing power and by warming up the coolant.

I guess if the battery is really empty (single digits %) the heater must be run from the mains.

 

[Rocky_H]

I'm pretty sure it IS running the battery heater when it shows 1A. However the heater is not run from mains, the power is taken from the battery.

I am almost certain that is not true. It is using mains power to run that battery heater as well. But the point is that it is only trying to display the CHARGING amps on that screen. So the extra several amps it is drawing through the plug that are going to run the battery heater are just not being included in that 1A number on the screen because they aren't going into charging yet.

 

[Zuikkis]

I am almost certain that is not true. It is using mains power to run that battery heater as well. But the point is that it is only trying to display the CHARGING amps on that screen. So the extra several amps it is drawing through the plug that are going to run the battery heater are just not being included in that 1A number on the screen because they aren't going into charging yet.

I can proof otherwise. I have an OpenEVSE charger that logs the actual power taken from the wall.

Now, here the charging started at 13:30. Tesla uses only very little power, maybe 150-200W. It even drops to zero a few times, then about 1h later it suddenly shoots to 3600W..

 

[Zuikkis]

Oh, also I do think the app shows the actual power taken, not just charge amps.

Sometimes when going on a long trip I charge to 100%. When near 100% charging is very low, it only takes a few amps. However when you start the cabin heater from the app, amps jump much higher. These amps are going to the cabin heater.

 

[Sudre]

My coolant heater on my 2013 Model S went out last year and I just ignored it. It was easier to put a space heater in the garage that I could turn on remotely an hour before I wished to charge. This month I decided to go ahead and fix it. I tested the coolant heater, even took the whole thing apart and there appears to be nothing wrong with it. It could be that once the heating element is submerged it short to the case thru the fluid. I am really curious where the relay is for turning this thing on and what tells that relay to turn on. I am beginning to think it's something wrong in the DC to DC converter.

I purchased one on eBay that is currently installed in the car. I won't know if it's working until I get a cold day. Service mode still shows a coolantHeater issue in the logs (do these clear themselves?). I still need to purge the air bubbles tho.

The relay must be in the DC to DC converter because the power cable connects directly to the converter. There is a reference line (the black wires) in with the main feed wires (orange) that just goes internally to the case of the heater....not really the case but a metal gasket like piece. Basically if you unplug the cable from the DC to DC converter it opens that connection and shuts down the coolant heating process. I imagine if the heater shorts to the case it also can sense that and shut down. There is also an overheat thermostat that comes out of the heater and goes into the cars wiring harness (Red wires).

SO my goal is in the long run to rebuild the original heater and add a 12 volt 200 watt (~17 amp) heater to the unit and connect it to one of the spare fuse spots in the fuss box. Then get a 12 volt remote switch. This way I can turn on MY battery heater whenever I want. Not much but a little something to get things started.

I am guessing the DC to DC converter senses the temp of the water entering the converter (for a Gen 1 DCtoDC converter at least) and uses that to determine if the heater should come on. The converter can also decide by the amount of power it is using if the heater needs to come on (since the heater and AC condenser go thru it). This could be why my heater is not coming on but the pump is running. There is no communication wiring going to the converter in a 2013 Model S so I don't know how else it is turning this thing on and off. Anyone have any ideas?