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How many coolant pumps does S have?

whitecotton

Member
Dec 31, 2015
155
17
Houston, Texas
He said DU as in display unit, Not the drive inverter I can definitely see that it makes a lot of heat.

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It seems like series would be used to heat the battery solely with the motors where as parallel is used to cool the motor and inverter . While the battery circulates its own stable coolest of the appropriate temperature because in that picture the battery coolant is 72degrees F
 

apacheguy

S Sig #255
Oct 21, 2012
5,085
1,246
So Cal
I'm pretty sure the DU does not get near warm enough to justify repurposing the heat.

It definitely does. Even Elon is on recording stating the Model S is designed to shunt heat from the DU to the battery pack in cold climates. This would be a condition where the coolant loop would be running in series.
 

whitecotton

Member
Dec 31, 2015
155
17
Houston, Texas
Display Unit ?! I don't think so, most likely Drive Unit (composed of the motor & inverter).


sorry i was thinking about the other DU, the display unit, the shows it has definitely been a long week. From my knowledge in off grid home inverters i can definitely understand the heat generation.

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IMG_4056.JPG


this is under the coolant tank on my vehicle, definitely a pump as it has wires going into it and the centrifugal shape. any thoughts as this appears to be a new find?
 

Mike K

Member
May 15, 2013
849
833
Los Angeles
sorry i was thinking about the other DU, the display unit, the shows it has definitely been a long week. From my knowledge in off grid home inverters i can definitely understand the heat generation.

- - - Updated - - -

View attachment 106902

this is under the coolant tank on my vehicle, definitely a pump as it has wires going into it and the centrifugal shape. any thoughts as this appears to be a new find?

I don't think it's a new discovery. I show it on my exploded parts diagram but I didn't download the corresponding parts list with the drive unit cooling loop diagram and it's in the drive unit loop, not the battery loop. So if it is a pump, it's for the drive unit.

Never mind, I have another bulletin that has drive unit pump info. It's referred to as "powertrain coolant pump 1".

So now this is confusing because if that's a pump and then there's a separate pump for the powertrain coolant loop up front then that means there's four total pumps because we know for sure there are two on the battery loop. I did happen to download the wiring diagrams for the entire car and they only refer to 3 pumps with an an open circuit for a fourth pump in the thermal management unit, though no reference to a 4th pump.

Would someone else access the manual please? I don't want to pay another $32 just to answer this question. :-D I'll tell you where you have to look. You just need the parts list for the motor coolant loop. It will answer the question right away. From the looks of it though, there are two pumps on each loop.
 
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JER

Member
Apr 25, 2015
294
26
Bristol, UK
I don't doubt that dual motor transmission has changed the cooling layout significantly. Given how torque sleep works, it would make sense to have an extra (separately controlled) coolant pump for the second drive unit. Could that be the third pump?
 

Mike K

Member
May 15, 2013
849
833
Los Angeles
If Whitecotton has a dual motor car, could it be the coolant pump for the front drive unit?

My diagrams are rear wheel drive specific and the picture of the pump he posted is accounted for in my diagrams. I can see exactly where in the drive unit loop it fits in. So I wouldn't say anything about that identifies a front motor.

Likewise, there shouldn't be any need for a third pump as the loop for the drive unit already circles the entire car and there are already two pumps up front on that loop. If I expected to see a third pump anywhere it would be at the rear of the car.
 

Kalud

Active Member
May 7, 2013
1,059
290
Montreal, QC
I don't see a path for the supposed use of waste heat for cabin heating. Only evaporator lines to HVAC.

That is correct; drive unit heat can be recycled only for warming the battery. It could still be saving some energy in cold weather though.

Yes unfortunately, the cabin cannot get any residual heat from the battery / Drive unit. The cabin gets heat only by the 6kW resistive PTC Heater, and cooled / dehumidified with the evaporator from the AC.
 

jaguar36

Active Member
Apr 10, 2014
2,069
1,570
NJ
Yes unfortunately, the cabin cannot get any residual heat from the battery / Drive unit. The cabin gets heat only by the 6kW resistive PTC Heater, and cooled / dehumidified with the evaporator from the AC.

The cabin can also be heated by the AC being used as a heat pump. This is the primary method of heating most of the time, the resistive heater only kicks in during particularly cold days, or right when the car starts up to warm up the cabin quickly.
 

islandbayy

Active Member
Feb 25, 2013
2,654
1,032
Greendale, Wisconsin
The cabin can also be heated by the AC being used as a heat pump. This is the primary method of heating most of the time, the resistive heater only kicks in during particularly cold days, or right when the car starts up to warm up the cabin quickly.
Incorrect, the Model S and Model X do not use Heat Pumps. They went with Resistive heating only.








As well, as I can assure you that the Model S has 3 cooling pumps. I know because all 3 have failed on my vehicle.
 

Kalud

Active Member
May 7, 2013
1,059
290
Montreal, QC
The cabin can also be heated by the AC being used as a heat pump. This is the primary method of heating most of the time, the resistive heater only kicks in during particularly cold days, or right when the car starts up to warm up the cabin quickly.

Unfortunately this is false and been discussed many times before.
 

Mike K

Member
May 15, 2013
849
833
Los Angeles
As well, as I can assure you that the Model S has 3 cooling pumps. I know because all 3 have failed on my vehicle.

I can say with a fair degree of certainty that you're wrong on this one. I posted a picture of my salvage car clearly showing three under hood and then with the fourth by the reservoir that makes four total. The diagrams I have for rear wheel drive cars corroborate all of this well, showing two pumps on each loop.

I think the confusion is in the different terms used to describe them but there are 4 pumps pushing coolant on two different connected loops.
 

Ingineer

Electrical Engineer
Aug 8, 2012
1,507
3,699
On all Model S cars I've looked at under the frunk box (close to 20 now) there are 3 Bosch centrifugal coolant pumps. 2 are run in series for added flow, but effectively show up as one in the thermal screen, but you can see them in Diag as separate units. It appears the 2 in series are in the powertrain loop, and the 1 is in the battery loop, but I'd have to double-check that one. There is a 4-way valve that can put the powertrain loop in series with the battery loop which lets waste heat from the powertrain warm the battery. It can also run in parallel with the systems in their own loops. There is a resistive heater in the battery loop that can heat the battery as well as a chiller that runs from the A/C system to cool it when supercharging. The powertrain is cooled by a radiator in front, and it has it's own bypass valve so it can be shut off when cooling isn't needed. (as well as louvers to block airflow and improve aero)

Sadly, there is no heat-pump capability. This low-cost addition could have made heating the Model S cabin way more efficient. Nissan put one in the Leaf in 2013.

Contrary to rumor and a early patent filed by Tesla, there is no way to use waste heat from the powertrain and/or battery to heat the cabin. Glycol never enters the cabin HVAC. It's sole means of heating is electric resistance.
 

ArtInCT

Always Learning
Sep 2, 2014
1,713
433
Southern Connecticut
Ingineer: In the battery loop, the resistive heater you mention, does it heat the glycol solution in that loop? Is that heater a high voltage heater?

Regarding the cabin resistive heater... Likewise is it a High Voltage unit i.e.: it is powered by the traction battery.??
 

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