[WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
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Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
good work! interesting approach with clocking holes for the leaf motor to get the "perfect" angle. looks like there is ample surface area over lap for the coupler. your going to likely crack a cv cage or blow the gearbox before the coupler comes remotely close to breaking! my 4mt (and coupler) is still going strong...and i have been very very very hard on it.
https://bratindustries.net/ leaf motor couplers, adapter plates, custom drive train components
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
nononononoonoononnnnoonononononononoonononononononoonononononononononooooooooooooooooooooo i let out some magic smoke 
Looking for some advice.
Setting up the WDR Automisering BMS today and it was going great. I downloaded the BusMust CAN GUI to confirm the CAN dongle works. I figured out how to download and open the WDR GUI and it seemed awake. Then i disconnected 12V while i plugged the Ioniq CMUs into the battery modules. First the orange CMU harnesses were plugged into the front and rear of each module then each CMU was connected to the large black connector on the harness in the order of 1-2-3-4. Then i smelled the magic smoke and about 10 seconds later saw a swirl of smoke coming out of the CMU connected to 2 where the yellow arrow is. AHHHHHHH! I frantically managed to unplug all the CMUs in about 10 seconds. The other 3 were cool to the touch and the hot one is smoked as you can see. The modules all measure between 23.84-23.87V.
Possible causes I can think of:
1. My first thought was that somehow HV leaked onto the LV wiring, but i don't think that is the case because i didn't see where anything was touching that that could have happened. The only way i could see that is if the exposed shielding of the twisted and shield pairs touched a battery terminal and somehow brought that into the circuit, but the shield aren't grounded anywhere yet and i would consider this pretty unlikely.
2. I assumed that the CMUs and BMS are inactive until powered on and i press go. After connecting everything up i was going to connect 12V and open up the GUI to read cell voltages and thought there would be a command to balance the cells if i wanted to. Now I'm wondering if the balancing is passive and when i connected the CMUs the balancing process began. I wasn't planning to balance the cells so i didn't reconnect all the modules. I highlighted with red lines which modules are connected and as you can see all 4 modules in the second set are connected AND the bottom module is also connected to the top module of the 1st set. I think the CMU began balancing 3 modules at 24V with one module at 48V.
3. The large grey deutsch connectors i made that made to string the CMUs together were only loosely fitted. For some reason i didn't push the plugs into the receptacles all the way so maybe some pins were only barely touching while other pins weren't touching at all. Only CAN is going through these connectors so idk how that could have caused a failure like this.
4. The CMU harness was connected "backwards". If the module plugs closest to the CMU are connected to the negative side of the string of 4 modules and the plugs furthest from the CMU are connected to the positive side of the string, would it be problematic to connect the harness backwards? Sets 1 and 2 are connected with the CMU closest to the negative module and sets 3 and 4 are connected with the CMU closest to the positive module.
Glad i still have all my fingers, toes, and modules! I wasn't wearing my HV gloves since i wasn't planning to doing HV stuff and that is a lesson learned.
Any help is appreciated!
Looking for some advice.
Possible causes I can think of:
1. My first thought was that somehow HV leaked onto the LV wiring, but i don't think that is the case because i didn't see where anything was touching that that could have happened. The only way i could see that is if the exposed shielding of the twisted and shield pairs touched a battery terminal and somehow brought that into the circuit, but the shield aren't grounded anywhere yet and i would consider this pretty unlikely.
2. I assumed that the CMUs and BMS are inactive until powered on and i press go. After connecting everything up i was going to connect 12V and open up the GUI to read cell voltages and thought there would be a command to balance the cells if i wanted to. Now I'm wondering if the balancing is passive and when i connected the CMUs the balancing process began. I wasn't planning to balance the cells so i didn't reconnect all the modules. I highlighted with red lines which modules are connected and as you can see all 4 modules in the second set are connected AND the bottom module is also connected to the top module of the 1st set. I think the CMU began balancing 3 modules at 24V with one module at 48V.
3. The large grey deutsch connectors i made that made to string the CMUs together were only loosely fitted. For some reason i didn't push the plugs into the receptacles all the way so maybe some pins were only barely touching while other pins weren't touching at all. Only CAN is going through these connectors so idk how that could have caused a failure like this.
4. The CMU harness was connected "backwards". If the module plugs closest to the CMU are connected to the negative side of the string of 4 modules and the plugs furthest from the CMU are connected to the positive side of the string, would it be problematic to connect the harness backwards? Sets 1 and 2 are connected with the CMU closest to the negative module and sets 3 and 4 are connected with the CMU closest to the positive module.
Glad i still have all my fingers, toes, and modules! I wasn't wearing my HV gloves since i wasn't planning to doing HV stuff and that is a lesson learned.
Any help is appreciated!
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
other lesson learned: whenever you get the feeling things are going well and you're doing great it is a surefire sign something is about to go wrong! That's happened three times in a row.
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
The redneckifiction of my garage (gararge as they say around here) is complete. IOW i built a plastic tent around my car workspace so i can work through the winter via space heater more comfortably. After a full day with the space heaters maxed out i got to 45F when it was 32F outside. ugh. it's going to be a long winter!
Then i had a call with Walter of WDR BMS fame and we started to get my BMS set up. It went really well except for realizing i think i killed another Hyundai Ioniq 5 battery module. When i was measuring cell voltages my probe touched two neighboring pins on a voltage sense connector. I didn't know not to do this because the cells are fused and now the module might be bricked A $200 FAFO. To reduce the timeline i'm going to get the car running with 12 modules (3 packs of 4 modules) instead of all 16. That way i don't have to source 2 more modules or build the 4th pack yet.
Then i got the first battery box built! I used a rolling pin mathod to get the thermal paste to the right height to barely touch the bottoms of the cells. I think my spacing worked out a well as i could have wanted. When i rest the module on the paste there's a .01-.03" gap between the mounting surface and the module. This gives a teeny bit of pressure on the cells, just enough to make them touch without deforming the pouches i hope. When i lift the module back up you can see a tiny bit of paste stuck to the cells and the very faintest outline of where they touched the thermal paste. I learned from the hyundai technical service manual that this paste gets installed as a 2-part mix, therefore i'm guessing it's much softer when the modules are installed at the factory than it is now. Hope i get some ok heat transfer out of this complex design i've made.
Next i started to install my motor mounts. that's going ok and the motor is now supported in the engine bay without a crane for the first time and that feels gooooooood! Gonna have to take them out for painting before final install.
Then i had a call with Walter of WDR BMS fame and we started to get my BMS set up. It went really well except for realizing i think i killed another Hyundai Ioniq 5 battery module. When i was measuring cell voltages my probe touched two neighboring pins on a voltage sense connector. I didn't know not to do this because the cells are fused and now the module might be bricked
A $200 FAFO. To reduce the timeline i'm going to get the car running with 12 modules (3 packs of 4 modules) instead of all 16. That way i don't have to source 2 more modules or build the 4th pack yet. Then i got the first battery box built! I used a rolling pin mathod to get the thermal paste to the right height to barely touch the bottoms of the cells. I think my spacing worked out a well as i could have wanted. When i rest the module on the paste there's a .01-.03" gap between the mounting surface and the module. This gives a teeny bit of pressure on the cells, just enough to make them touch without deforming the pouches i hope. When i lift the module back up you can see a tiny bit of paste stuck to the cells and the very faintest outline of where they touched the thermal paste. I learned from the hyundai technical service manual that this paste gets installed as a 2-part mix, therefore i'm guessing it's much softer when the modules are installed at the factory than it is now. Hope i get some ok heat transfer out of this complex design i've made.
Next i started to install my motor mounts. that's going ok and the motor is now supported in the engine bay without a crane for the first time and that feels gooooooood! Gonna have to take them out for painting before final install.
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Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
Got everything installed for the first time! This is just temporary for fabricating the motor mounts and getting cable and hose lengths. Now it all has to come back out for painting the motor mounts. It's a bit of a messy look, but so psyched i got it all to fit with 1/4 of the batteries under the hood! The motor is clocked at 45 degrees which makes a lot of odd shapes for fitting everything else in. My 3D scanner lied to me a little bit and I have to mod the battery box mounts to bring it an inch lower and half an inch forward.
motor and PDM
motor, PDM, and PRA
motor, PDM, PRA, and battery box!
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
After a great winter of skiing instead of working on the car i am BACK to getting dirty in the garage and making my housemates roll their eyes at me!
Starting with the side quest of getting a heater working. It seems nobody as hacked the leaf PTC cabin heater (the air kind, not the water kind). Since i have one i want to make it work.
PTC air heater goals:
1. power level adjustable to at least 2 levels (preferably 5+ if it's not much more complicated)
2. use existing blue to red slider in the dash
3. no fires or melting or stinky smells allowed (iow thermal cutoff switch)
constraints:
1. 400V battery pack
2. 12V available for control
3. must fit in existing space of the old heater core below the glove box
4. can only turn on if the fan is running
5. minimize fancy electronics, try to find canned solution
6. nominal 5kw power in OEM heater
what kind of circuit should i use to modulate the power to the heater??
- some how need to adjust the current thru the heater i think (can you tell i'm not an electrical engineer yet?)
1. first thought was a relay driven by a slow pulse (where in the world do i get a slow, controllable pulse from?)
2. some people talk about using an arduino
3. EE coworker suggested a custom amplifier kind of circuit
4. HVAC friend suggested "heat card SCR"
After 2 days of research i was fairly certain the path for me a solid state relay driven by a controller that can turn a potentiometer into a low frequency PWM (2-10s cycle time).
Notes of SSRs and heater controllers:
1. AC SSRs use a different circuit than DC SSRs, and therefore are not interchangeable
2. SSR is a pretty broad term. there are different kinds of switches inside SSRs (MOSFET, IGBT, etc)
3. low voltage options are bountiful, but 400V rated options aren't.
4. some low voltage or AC SSRs have built in controllers, some even specifically for heaters! but i couldnt find one with a 400VDC rating.
5. there are a billion types of board that convert an analog input (0-5V, 0-12V, etc) (created by a potentiometer) into PWM output. I want one that creates slow pulses so my relay doesn't reach its cycle lifespan in a few years.
Before i bought anything i checked if the heater was one single core or multiple cores stuck together. Turns out it is made of 8 cores! They measure 600 Ohm across each. They have fast-on-esque tab connections to the OEM controller which is easily removed. I didn't know it came off easily so i tried hacking it off first). Each heating element is a simple strip of resistive material sandwiched to an aluminum plate and fins thru a (assumed) thermally-conductive-electrically-insulating gap pad.
Having 8 different elements gives me slightly different constraints. I now have the option to power a sub set of the cores for lower power heat instead of delivering reduced power to all 8 cores. I will research that tomorrow!
I have some Ohms law questions here.
Based on the OEM numbers i would expect the heater to have a resistance of 32Ohms:
I=P/V=5000W/400V=12.5A
R=V/I=400V/12.5A=32Ohm
600Ohms across each of 8 elements gives 75Ohms
R=600/8=75Ohms
I=V/R=400V/75Ohms=5.3A
P=IV=5.3A*400V=2120W or P=I^2*R=2106W ---> why are these different?
This is confusing to me because as it heats up the resistance will increase and current will decrease and power will decrease. 2kW would be pretty disappointing, does anyone know why the resistance doesn't appear to match OEM claims?
Starting with the side quest of getting a heater working. It seems nobody as hacked the leaf PTC cabin heater (the air kind, not the water kind). Since i have one i want to make it work.
PTC air heater goals:
1. power level adjustable to at least 2 levels (preferably 5+ if it's not much more complicated)
2. use existing blue to red slider in the dash
3. no fires or melting or stinky smells allowed (iow thermal cutoff switch)
constraints:
1. 400V battery pack
2. 12V available for control
3. must fit in existing space of the old heater core below the glove box
4. can only turn on if the fan is running
5. minimize fancy electronics, try to find canned solution
6. nominal 5kw power in OEM heater
what kind of circuit should i use to modulate the power to the heater??
- some how need to adjust the current thru the heater i think (can you tell i'm not an electrical engineer yet?)
1. first thought was a relay driven by a slow pulse (where in the world do i get a slow, controllable pulse from?)
2. some people talk about using an arduino
3. EE coworker suggested a custom amplifier kind of circuit
4. HVAC friend suggested "heat card SCR"
After 2 days of research i was fairly certain the path for me a solid state relay driven by a controller that can turn a potentiometer into a low frequency PWM (2-10s cycle time).
Notes of SSRs and heater controllers:
1. AC SSRs use a different circuit than DC SSRs, and therefore are not interchangeable
2. SSR is a pretty broad term. there are different kinds of switches inside SSRs (MOSFET, IGBT, etc)
3. low voltage options are bountiful, but 400V rated options aren't.
4. some low voltage or AC SSRs have built in controllers, some even specifically for heaters! but i couldnt find one with a 400VDC rating.
5. there are a billion types of board that convert an analog input (0-5V, 0-12V, etc) (created by a potentiometer) into PWM output. I want one that creates slow pulses so my relay doesn't reach its cycle lifespan in a few years.
Before i bought anything i checked if the heater was one single core or multiple cores stuck together. Turns out it is made of 8 cores! They measure 600 Ohm across each. They have fast-on-esque tab connections to the OEM controller which is easily removed. I didn't know it came off easily so i tried hacking it off first). Each heating element is a simple strip of resistive material sandwiched to an aluminum plate and fins thru a (assumed) thermally-conductive-electrically-insulating gap pad.
Having 8 different elements gives me slightly different constraints. I now have the option to power a sub set of the cores for lower power heat instead of delivering reduced power to all 8 cores. I will research that tomorrow!
I have some Ohms law questions here.
Based on the OEM numbers i would expect the heater to have a resistance of 32Ohms:
I=P/V=5000W/400V=12.5A
R=V/I=400V/12.5A=32Ohm
600Ohms across each of 8 elements gives 75Ohms
R=600/8=75Ohms
I=V/R=400V/75Ohms=5.3A
P=IV=5.3A*400V=2120W or P=I^2*R=2106W ---> why are these different?
This is confusing to me because as it heats up the resistance will increase and current will decrease and power will decrease. 2kW would be pretty disappointing, does anyone know why the resistance doesn't appear to match OEM claims?
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Bratitude
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Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
why not just get a can or lin or what ever it is (assuming its canbased) log and go from there??
https://bratindustries.net/ leaf motor couplers, adapter plates, custom drive train components
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tom91
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Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
The leaf PTC has been throughly reverse engineered as it breaks alot.
https://pufferfish.pl/repairing-heating ... ptc-heater
https://github.com/dalathegreat/Nissan- ... ngineering
https://pufferfish.pl/repairing-heating ... ptc-heater
https://github.com/dalathegreat/Nissan- ... ngineering
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
i'm still only just barely starting to work with the CAN system for my BMS so CAN and LIN are still scary unknowns to me. maybe once i learn how to work with CAN i'll realize that would have been easier. i heard this unit communicates on a LIN bus. i've thoroughly destroyed the controller for this heater so both are out of the question now haha
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
That PTC water heater has been sorted out, but i'm using the air cabin heater. Pictures below will clarify. if you've seen this reverse engineered please let me know!tom91 wrote: ↑Wed Apr 08, 2026 8:30 am The leaf PTC has been throughly reverse engineered as it breaks alot.
https://pufferfish.pl/repairing-heating ... ptc-heater
https://github.com/dalathegreat/Nissan- ... ngineering
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
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Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
got the wrong top picture above.
^ complete air PTC heater located in my heating duct
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
On this page there is a small section talking to the Nissan Leaf dry PTC heater.
https://ev-olution.yolasite.com/nissan- ... roller.php
I haven't tried it yet as I'm not up to that stage in my build yet.
https://ev-olution.yolasite.com/nissan- ... roller.php
https://ev-olution.yolasite.com/resourc ... r_V1.1.rarUPDATE. I am also sharing controller code for "dry" PTC heater (from LEAF made after 2013). It was tested and reported as fully working. Please only use it if you using PTC in custom project and not in LEAF vehicle. As LEAF made after 2013 has two other slave modules connected to LIN bus. Code for "dry" PTC:
I haven't tried it yet as I'm not up to that stage in my build yet.
Re: [WIP] 1979 Subaru Wagon: Leaf Stack,Zomb,Ioniq 5 1/2 pack
oh man wish i had seen that before hacking mine upcnstrct wrote: ↑Thu Apr 09, 2026 6:22 am On this page there is a small section talking to the Nissan Leaf dry PTC heater.
https://ev-olution.yolasite.com/nissan- ... roller.php
https://ev-olution.yolasite.com/resourc ... r_V1.1.rar
I haven't tried it yet as I'm not up to that stage in my build yet.