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Discussion Starter #1
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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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.

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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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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:D 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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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.

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).

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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Discussion Starter #9
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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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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Discussion Starter #11
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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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 :eek:
 

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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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Discussion Starter #15
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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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???

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?

my biggest concern is overheating the battery and the risk of fire if you get this wrong :eek:
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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Bought one today too!

And to get back to my own question asked earlier
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?
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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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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