# Anyone using OEM Tesla battery heaters?



## Jimbo69ny (Feb 13, 2018)

I see a bunch on ebay for a reasonable price. I am wondering if anyone has used them to heat Tesla modules or full packs. I haven't seen one in person but it would seem pretty straight forward.

I searched but surprisingly I didn't find any threads about it.

Do they require any CAN data to activate?
From what I can tell there are 2 small wires and 2 larger wires. Presumably switched power and main power. Looks like it can take 450 volts directly from the battery.


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## Kevin Sharpe (Jul 4, 2011)

Jimbo69ny said:


> I am wondering if anyone has used them to heat Tesla modules or full packs. I haven't seen one in person but it would seem pretty straight forward.
> 
> I searched but surprisingly I didn't find any threads about it.


Damien, Jeff, and my builds are all using the Tesla fluid heater. Mine is for battery heating, and iirc the others are for cabin heating.



Jimbo69ny said:


> Do they require any CAN data to activate?
> From what I can tell there are 2 small wires and 2 larger wires. Presumably switched power and main power. Looks like it can take 450 volts directly from the battery.


It's a 'dumb' device which in the Tesla Model S uses a PWM control circuit in the Front HVJB. More info here


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## Jimbo69ny (Feb 13, 2018)

Kevin Sharpe said:


> Damien, Jeff, and my builds are all using the Tesla fluid heater. Mine is for battery heating, and iirc the others are for cabin heating.
> 
> It's a 'dumb' device which in the Tesla Model S uses a PWM control circuit in the Front HVJB. More info here


So I would need a PWM too? 

This is the part I found. https://www.ebay.com/itm/Genuin-Tes...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649


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## Kevin Sharpe (Jul 4, 2011)

Jimbo69ny said:


> So I would need a PWM too?


PWM is used to control the amount of heat generated... I would suggest you use the PWM circuit in the Tesla Front HVJB because it's designed for the job, cheap, and a simple device that will also connect the Tesla DCDC, PTC Heater, and A/C compressor if required.


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## Jimbo69ny (Feb 13, 2018)

Kevin Sharpe said:


> PWM is used to control the amount of heat generated... I would suggest you use the PWM circuit in the Tesla Front HVJB because it's designed for the job, cheap, and a simple device that will also connect the Tesla DCDC, PTC Heater, and A/C compressor if required.


So many acronyms! lol


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## Kevin Sharpe (Jul 4, 2011)

Jimbo69ny said:


> So many acronyms! lol


 if it's helpful in full English let me know... I assume people understand the acronyms but no problem if not.


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## Jimbo69ny (Feb 13, 2018)

Kevin Sharpe said:


> if it's helpful in full English let me know... I assume people understand the acronyms but no problem if not.


What is PWM? I assume HVJB is high voltage junction box.

Seems like a lot to add when I only need a fluid heater and circulator pump.


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## Kevin Sharpe (Jul 4, 2011)

Jimbo69ny said:


> What is PWM?


Pulse Width Modulation (here) is used to control the power delivered to a device... it's widely used in cars, controlling the radiator fan speed for example.



Jimbo69ny said:


> I assume HVJB is high voltage junction box.


Correct, Tesla use two in the Model S/X... one at the front (here) and one at the rear (here).



Jimbo69ny said:


> Seems like a lot to add when I only need a fluid heater and circulator pump.


You'll need to control the heater power somehow otherwise it will simply boil the water in your system... the front HVJB is a very cheap and convenient water proof power controller that would interface easily to your control system (Arduino for example).


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## Jimbo69ny (Feb 13, 2018)

Kevin Sharpe said:


> Pulse Width Modulation (here) is used to control the power delivered to a device... it's widely used in cars, controlling the radiator fan speed for example.
> 
> Correct, Tesla use two in the Model S/X... one at the front (here) and one at the rear (here).
> 
> You'll need to control the heater power somehow otherwise it will simply boil the water in your system... the front HVJB is a very cheap and convenient water proof power controller that would interface easily to your control system (Arduino for example).


What about simply paralleling off of the existing cooling system? I know that will increase the load on the OEM cooling pump, I wonder if it would be ok. The OEM coolant connections are in the front of the pack. I would have to add a T and run lines to the rear. I would have to monitor flow to make sure the rear pack was actually cooled and heated. 

Sure a stand alone system would probably be best.


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## Jimbo69ny (Feb 13, 2018)

Jimbo69ny said:


> What about simply paralleling off of the existing cooling system? I know that will increase the load on the OEM cooling pump, I wonder if it would be ok. The OEM coolant connections are in the front of the pack. I would have to add a T and run lines to the rear. I would have to monitor flow to make sure the rear pack was actually cooled and heated.
> 
> Sure a stand alone system would probably be best.



I read the thread you posted about the front HVJB. Seems like I would need to know CAN to do that. I dont. CAN is over my head and I havent found a place to learn. I've watched youtube videos but without spending thousands on oscilloscopes and whatever other equipment I would need, I dont know how I could practice. Not really too eager to until that is my only option. Id rather find a 12 volt solution.


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## Jimbo69ny (Feb 13, 2018)

I am thinking a Tesla battery fluid heater https://www.ebay.com/itm/ELECTRIC-B...m=282566278938&_trksid=p2047675.c100752.m1982

Plus a fluid pump https://www.ebay.com/itm/22L-m-348G...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

Plus some kind of 12v trigger. I have buddy who knows CAN and is working on a controller for a spare Tesla Rav4 EV pack that I have. I just asked him if he will be able to trigger the pump and heater using his controller. If not, I will be able to monitor the temps and flip a manual switch on my dash.


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## Kevin Sharpe (Jul 4, 2011)

Jimbo69ny said:


> I have buddy who knows CAN and is working on a controller for a spare Tesla Rav4 EV pack that I have. I just asked him if he will be able to trigger the pump and heater using his controller.


The pumps and battery heater use PWM not CAN (see attached schematic). They are controlled by the "Tesla Thermal Controller" (TTC) which uses CAN to communicate with the car. The TTC could be reverse engineered but it's not a trivial task.

I'd recommend you try and find a local electronics engineer who understands PWM and Arduino. It would be easy to drive the pumps and heater (via the front HVJB) using 12V PWM from the Arduino and develop your control software... my biggest concern is overheating the battery and the risk of fire if you get this wrong


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## DrJeff (Apr 24, 2015)

Tesla PWM pump and diverter valve control details found on this segment of my thread for the TesLorean...

Jeff


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## oudevolvo (Mar 10, 2015)

While searching and researching on the Tesla battery heater I find it listed under several numbers:
1028689-00-B 
1009508-00-E
1038901-00-G
1038901-00-H
Does anyone know whether there is any logic in those part numbers?
Does the letter perhaps indicate the generation and thus 1038901-00-H being the newest model?

And does anyone know whether there are differences between them?
I’ve seen them advertised as 2,5kW but also with stickers on them being 5,5kW.

Whicht both seems quite a lot so I would want to implement PWM control to reduce power. But is there a PWM control / signal line?


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## Jimbo69ny (Feb 13, 2018)

I just picked up my circulator pump. I bought this one on ebay. Its the same pump that Jack sells on EVTV but cheaper. https://www.ebay.com/itm/22L-m-348GHP-DC12V-High-Temperature-80C-Brushless-Water-pump/151270327261?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I still dont know if I should buy a Tesla water heater or not.

I have a lot of experience with home solar hot water heating systems. I am tempted to put a solar hot water panel on top of my battery trailer and call it a day.


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## Jimbo69ny (Feb 13, 2018)

I just purchased a Tesla fluid heater. Best deal I have seen. Only $65 shipped.
https://www.ebay.com/itm/NEW-2014-1...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649


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## oudevolvo (Mar 10, 2015)

Jimbo69ny said:


> I just purchased a Tesla fluid heater. Best deal I have seen. Only $65 shipped.


Congrats! Not expensive at all.


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## oudevolvo (Mar 10, 2015)

Kevin Sharpe said:


> The pumps and battery heater use PWM not CAN (see attached schematic).


Unfortunately I do not understand the schematic. Hope you can elaborate on the heater wiring.
Looking at images of the heater om the web I see two connectors.
One is a 2-pin orange HV. The other one is a 2-pin black connector.
What are these?
Is one of these pins in the black connector a PWM control pin? And a thermistor???



Kevin Sharpe said:


> It would be easy to drive the pumps and heater (via the front HVJB) using 12V PWM from the Arduino and develop your control software...


Is my understanding correct from other posts that the Front HCJB is just forwarding the PWM signal so the same control software can be used directly on the heater?



Kevin Sharpe said:


> my biggest concern is overheating the battery and the risk of fire if you get this wrong


Yes, agree, you could cook the modules in theory. However, even if the heating control software fails to stop heating above a certain temperature the BMS is there as a failsafe. At least the BMS I’m using (Libal n-BMS) can be configured to trigger a temperature based error and open all contactors so it cannot escalate. But I agree heating batteries remains delicate. Earlier I anticipated on using a 220V Defa heater with integrated thermostat at 40 degrees. Later I planned to use a 220V Defa PTC heater and currently I am thinking about using a Tesla battery heater.


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## oudevolvo (Mar 10, 2015)

Bought one today too!

And to get back to my own question asked earlier


oudevolvo said:


> While searching and researching on the Tesla battery heater I find it listed under several numbers:
> 1028689-00-B
> 1009508-00-E
> 1038901-00-G
> ...


There are two generations. 
1028689-00-* and 1009508-00-* are Gen 1. and are Philips & Temro Zerostart units. From modelyear 2015 onwards Tesla switched to LG heaters and have number 1038901-00-*. 

Next challenge is how to PWM control it.


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## DrJeff (Apr 24, 2015)

My Tesla coolant heater is from a 2015 70D car. It has 2 HV wires that connect via the grey connector to the Front HVJB. There are only two LV wires, colored DB-WH and BK-GY.

From the wiring diagrams, the LV wires (after a connector) correspond with wiring from the Tesla Thermal Controller module.

CoolantHtrExitTempSens
DB-WH : Tamb
BK-GY : AGND

The first LV wires out of the heater are Red and White. From the alignment of the wiring in the connector, I would guess that the White wire connects to the DB-WH wire running to the Thermal Controller.

At the Front HVJB, the two HV lines (via the grey connector) from the coolant heater run to a section of the control board that appears to hold three high voltage transistors (perhaps not the correct technical term). The Front HVJB also get PWM signals. The AC compressor is direct CAN, the PTC heater is direct CAN, and the DCDC is CAN controlled... So the PWM lines into the Front HVJB must control the HV voltage to the Coolant Heater. So in this configuration you would need the Front HVJB to adjust the heating properties of the coolant heater.

Jeff


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## oudevolvo (Mar 10, 2015)

Thanks Jeff for the elaborate answer and information.
From the above I'm not sure what "BK-GY : AGND" on the LV side is. Perhaps just ground?
But nevertheless building on whay you are saying the black wire on the heater unit looks more like just a thermistor to measure outgoing water temperature from the heater.
If I understand it correctly: Tesla is using HV PWM to control the heater and reduce the power.

Implementing HV PWM at approx 10 Amps and 355V seems like a totally different ballgame than PWM controlling a 12V Pierburg pump. Not really my cup of tea.
Nor is using a HVJB + Thermal controller in my build.

I'll continue exploring possibilities but I'm afraid my only option is to run it at full-power on/off using a contactor and the HV lines.


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## Kevin Sharpe (Jul 4, 2011)

oudevolvo said:


> Implementing HV PWM at approx 10 Amps and 355V seems like a totally different ballgame than PWM controlling a 12V Pierburg pump. Not really my cup of tea.
> Nor is using a HVJB + Thermal controller in my build.


The Front HVJB has the relevant HV circuit and is often available for under 100 USD. It's a simple way of adding PWM control to the Battery Heater and for distributing HV for features like DCDC, AC Pump, etc.



oudevolvo said:


> I'll continue exploring possibilities but I'm afraid my only option is to run it at full-power on/off using a contactor and the HV lines.


I suspect your contactor will not like switching the battery heater on/off at full load continuously. You'll need to check the contact ratings and duty cycle. 

PWM really is the way to go... in the next few weeks we will have several cars using the Tesla Battery Heater and will share the knowledge


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## oudevolvo (Mar 10, 2015)

Thanks Kevin!
Well, I guess at least including the HVJB is on then.
I think I'm starting to understand it. Also after reading your topic on "Hacking the Tesla Model S Front Junction Box" in particular of what Tom writes.


Tomdb said:


> the battery heater just needs a pwm into the junction box.


and yourselves


Kevin Sharpe said:


> Fuse F1 (20A) connects the HV to the "Grey" connector via three IPB60R099CPA MOSFETs (here) and a .005R WSL2726 resistor (here). I suspect the busy power circuit is controlling the MOSFETs and has no connection with the other fused supplies.


So I can just feed 12V PWM into the front HVJB (signal characteristics to be discovered) and the Front HVJB translates that into HV PWM. And there is no need to also include the Thermal controller.

I'm also exploring the possibilities for adding A/C to my project and a Tesla pump is one of the options. In that case the Front HVJB perhaps also comes in handy. I'm not so much into CAN-BUS but I am eager to learn. Especially since the Lithium Balance n-BMS is quite CAN driven.

Will keep my eyes open for a reasonably priced front HVJB in the EU. Current offerings I can find are EUR 300+. Or otherwise buy one in the US if I can indeed find it for around $100. Assume I will need to by a cable (1030582-00-D) as well to have the right connector to feed power into the module.

Thanks! This is going to be an interesting journey.


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## Kevin Sharpe (Jul 4, 2011)

oudevolvo said:


> So I can just feed 12V PWM into the front HVJB (signal characteristics to be discovered) and the Front HVJB translates that into HV PWM.


It's possible the PWM signal is 3.3V to 5V rather than 12V... all will be revealed in the near future 

Don't forget that you can also use the Tesla DCDC converter to provide 12V for your system.. that plugs into the Front HVJB using a single cable


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## oudevolvo (Mar 10, 2015)

Kevin Sharpe said:


> It's possible the PWM signal is 3.3V to 5V rather than 12V... all will be revealed in the near future


Thanks for the warning! I'm looking forward to the details. Thanks for all the efforts in reverse engineering all this AND making it publicly available.



Kevin Sharpe said:


> Don't forget that you can also use the Tesla DCDC converter to provide 12V for your system.. that plugs into the Front HVJB using a single cable


Yes, I played around with that idea in my head. I saw Damiens update over the last weekend that he had it up and running.
It's tempting especially since I like doing things 'just because you can'.
However in this case, I have my DC/DC already mounted in the car and even found the corresponding plug for the control connector.
Even though I like exploring I need to make sure I get my project finished as well. So for the DC/DC maybe next time...


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## DrJeff (Apr 24, 2015)

oudevolvo said:


> ...Assume I will need to by a cable (1030582-00-D) as well to have the right connector to feed power into the module....


The HV wiring into the (2015) Front HVJB are just two orange cables that end in ring terminals (no special port - but there is a fancy grommet/cable securing mechanism). When the Front HVJB lid is off, there is even a little door in the (orange) protective cover that provides access to the bolts through the ring terminals.

Jeff


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## oudevolvo (Mar 10, 2015)

DrJeff said:


> The HV wiring into the (2015) Front HVJB are just two orange cables that end in ring terminals (no special port - but there is a fancy grommet/cable securing mechanism).


Thanks! Yes, I assumed I needed that fancy securing mechanism to preserve IP rating and keeping the box watertight. Found it on this Autobahn photo as well.








But perhaps I can just add screw thread in de casing and use my own metal EMC glands.


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## Jimbo69ny (Feb 13, 2018)

Can anyone post the dimensions of the Tesla Battery Heater? Mine is on my way but not in my hand yet. I am working its home tonight and I need to make sure I leave enough space.

Many thanks!


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## DrJeff (Apr 24, 2015)

Jimbo69ny said:


> Can anyone post the dimensions of the Tesla Battery Heater? Mine is on my way but not in my hand yet. I am working its home tonight and I need to make sure I leave enough space.
> 
> Many thanks!


Depth 4in (including the bracket - bracket probably adds 1/5in to width)

Width 7 1/2in (incl's 1in of coolant pipe outlet, so once hose attached it will probably take up another inch - even if the hose bends out of the way quickly)

Height 7 7/8in (incl's 1in of coolant pipe outlet, so once hose attached it will probably take up another inch - even if the hose bends out of the way quickly)

Jeff


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## Jimbo69ny (Feb 13, 2018)

DrJeff said:


> Depth 4in (including the bracket - bracket probably adds 1/5in to width)
> 
> Width 7 1/2in (incl's 1in of coolant pipe outlet, so once hose attached it will probably take up another inch - even if the hose bends out of the way quickly)
> 
> ...


Awesome! Thank you!


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## Jimbo69ny (Feb 13, 2018)

It is looking like the smaller two wires are a thermistor. The larger 2 wires are obviously HV. I thought the smaller wires would be a switch but its not looking like that is the case. The resistance of the 2 wires changes with temperature.

If you are interested I created a google doc to document the resistance at different temperatures. 
https://docs.google.com/spreadsheets/d/1u4Y_bB8EBBnw36TMK_wG7xjk1fXnhC1gdV_QfIZ922w/edit?usp=sharing


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