Water Heater

[johu]

Before putting this up in our EV parts list I wanted to discuss it first:

https://www.ebay.de/itm/Standheizung-Zu ... 0613045461
or this
https://www.owlheizer.de/OWLHeizer-OWL-4S-70C-2000-Watt



It's a 230V heater with integrated pump and temperature regulation.

So it can obviously be used to preheat the car when stationary with grid power. And I reckon with a 50 Hz chopper circuit it would work from 400V DC as well, provided the pump likes that.

I would separate the cooling loop from the motor because it wouldn't make much sense to waste energy by heating up the thermal mass of the motor, right?

Any experience with stuff like that?

[bobby_come_lately]

I have bought one of these and modified it to remove the pump - see photo. Planning to use it in a closed loop for my heater with an external DC pump and thermostat.

Not got further than modifying it though.

[Note, I didn't just cut the impeller off. I've also disconnected and removed the motor from the other side but couldn't find that photo.]

[prensel]

I'm actually looking into the Calix PH heater, which is also a 2000W/230VAC heater, as a replacement for the MES-DEA RM3 heaters. What would it take to get it to work on 385VDC instead of 230VAC ?

[johu]

I'm actually looking into the Calix PH heater, which is also a 2000W/230VAC heater, as a replacement for the MES-DEA RM3 heaters. What would it take to get it to work on 385VDC instead of 230VAC ?

If we just talk heater (without pump) I'd simply use an isolated gate driver and a TO-247 IGBT and clock that with 70% dutycycle at a few 10s of Hz.
If the integrated pump is just a DC motor with a rectifier it would run as well.

In my Polo conversion I switch the air heating element with an IGBT, just without the clocking.

I would probably integrate it with the VCU that can generate the PWM on one of it's open collector outputs when selected via the web interface or at some outside temperature threshold.

EDIT: I've ordered it now, lets see

[ZooKeeper]

When I was looking to convert a liquid cooled vehicle, I planned to use a 240v on demand water heater. I have also seen folks install a 240v engine block heater element in-line with a pump.

The liquid circuit was planned as: Tank > Pump > Controller > Motor(?) > Heater > Heater Core (stock) > Radiator > Tank

In this way the Heater would not add heat unless needed and then only to the vehicle's heater core and not the EV components.

https://www.faucetdepot.com/prod/Chrono ... 182349.asp

[bobby_come_lately]

When I was looking to convert a liquid cooled vehicle, I planned to use a 240v on demand water heater. I have also seen folks install a 240v engine block heater element in-line with a pump.

The liquid circuit was planned as: Tank > Pump > Controller > Motor(?) > Heater > Heater Core (stock) > Radiator > Tank

In this way the Heater would not add heat unless needed and then only to the vehicle's heater core and not the EV components.

https://www.faucetdepot.com/prod/Chrono ... 182349.asp

This is another option for me, though it may require me to increase the size of my radiator to dump the excess heat. Saves on a second pump and gives me extra cooling. But decreases the efficiency of the heating loop.

[prensel]

If we just talk heater (without pump) I'd simply use an isolated gate driver and a TO-247 IGBT and clock that with 70% dutycycle at a few 10s of Hz.
If the integrated pump is just a DC motor with a rectifier it would run as well.

In my Polo conversion I switch the air heating element with an IGBT, just without the clocking.

I would probably integrate it with the VCU that can generate the PWM on one of it's open collector outputs when selected via the web interface or at some outside temperature threshold.

EDIT: I've ordered it now, lets see

Yes just as a heater, similar to the RM3, as the 12V pumps are all external.
Problem with the RM3 is that the electronics always burnup at some point wheres as the element is still okay.
Since the electronics are potted on the bottom of the boiler its not fixable.

Thought of building some external logic with a beefy mosfet to control the heater coil and re-use the RM3 boiler (I allready have a couple with the same problem laying around).

[celeron55]

My experience with water heaters is I bought a 2kW (or so) DEFA one with no internal pump, gutted the AC rated thermostat and added my own temperature sensor. I switch DC to it using a DC rated contactor. My battery voltage is 300V fully charged. It's lasted for 2 years so far.

Before I gutted the AC rated thermostat, I destroyed it with a 300V DC arc during initial test runs. Not recommended. Takes hours to clean up the mess.

[arber333]

My experience with water heaters is I bought a 2kW (or so) DEFA one with no internal pump, gutted the AC rated thermostat and added my own temperature sensor. I switch DC to it using a DC rated contactor. My battery voltage is 300V fully charged. It's lasted for 2 years so far.

Before I gutted the AC rated thermostat, I destroyed it with a 300V DC arc during initial test runs. Not recommended. Takes hours to clean up the mess.

This here is really good and cheap option. You just need to put it in an enclosuse with some isolation (electrical and heat).
viewtopic.php?f=9&t=335#p3783

However i really dont trust those tube AC heaters. There is sand/quarc inside and special wire that heats up under current. However there is a good chance that wire will conduct 360Vdc to casing and you would have a partial short through coolant. It is enough to throw protection in EVSEs. Ask me how i know .

[Martin1775]

I've repaired the RM3 heater in my Think, removing the potting compound is no fun.
The original PWM control with a PIC is designed in such a way that the 55A fuse triggers when it is permanently on, as well as for safety in the event of excess temperature due to a short circuit in the heating to kill the fuse.
I continued to use the original temperature sensor (LM335) and switched the heating coil in series instead of original parallel. These are accessible from the top. An IGBT (IRG4PC50) with opto driver(HPCLJ312) as a switch, supplied via a series resistor, elcap and Z-diode. HV fuse with 16A. Temperature control with an OPV as a comparator and supply via 12V (heater on).
I also used the overtemperature protection again, but the switch is only accessible after removing the potting compound.
To my regret, i have not created a complete circuit diagram.

[ZooKeeper]

Soooo very glad to have an Aircooled Project -

[prensel]

I've repaired the RM3 heater in my Think, removing the potting compound is no fun.
The original PWM control with a PIC is designed in such a way that the 55A fuse triggers when it is permanently on, as well as for safety in the event of excess temperature due to a short circuit in the heating to kill the fuse.
I continued to use the original temperature sensor (LM335) and switched the heating coil in series instead of original parallel. These are accessible from the top. An IGBT (IRG4PC50) with opto driver(HPCLJ312) as a switch, supplied via a series resistor, elcap and Z-diode. HV fuse with 16A. Temperature control with an OPV as a comparator and supply via 12V (heater on).
I also used the overtemperature protection again, but the switch is only accessible after removing the potting compound.
To my regret, i have not created a complete circuit diagram.

What did you use to remove the potting ? Mechanical or chemical ?
I tried it with one heater on the mill trying to mill out the whole potting/pcb area but the 'stone' type big fuse was not very forgiveable to my metal milling cutter....

[Martin1775]

I used a knife to remove the compound. The first thing I did was uncover and removing the connectors, then the fastening screws.
There are three screws PH1 that hold the board (white arrows), three that fix the IGBT's under the board (blue arrows) and two screws for the thermal switch.

After exposing and removing the screws, I peeled off the compount around the circuit board and pulled it out with a lever. It is possible that the thermal switch and screws can only removed after removing the PCB. You get easier access when removing the fuse first, but in my case a screw turned with the nut so it was not possible.
There are some infos and solutions at https://www.fingers-welt.de/phpBB/viewt ... 14&t=11820 but i have implemented a less complex solution.

[johu]

Got the heater yesterday. It can simply be opened by removing 4 bolts. I cut the wire to the AC motor and put it back together. The heating element looks like a square mushroom surrounded by water, maybe like 5x8cm

[johu]

Tested the heater today. I basically placed right before the input of the cabin heater. So it's inverter -> motor -> pump -> heater -> cabin -> inverter. To my dismay everything got warm except the cabin. It doesn't seem like the radiator extracts a whole lot of heat from the water even with the fan turned half way up. Is that normal?

So I think I will try the PTC route next. Apparently the Diesel version of Touran has a slot in PTC element (part number 5Q0963235A)
https://www.ebay.de/itm/Elektrischer-Zu ... 3449719000

Only problem there: my DC/DC converter only sports 750W so I either need a larger one or derate the heater. I think it has CAN control anyway.

EDIT: I could also create a loop just for the cabin heater. So one more reservoir, one more pump. How does that sound?

[slow67]

EDIT: I could also create a loop just for the cabin heater. So one more reservoir, one more pump. How does that sound?

That’s what I would do. The inverter doesn’t like to be warm, but you do!

That’s also how Ive seen several OEMs do it.

[FJ3422]

.... I think it has CAN control anyway.

As far as I know only the Tesla heaters have CAN. Most of the auxilary electric heaters have a LIN interface. You can pass the internal electronics and directy supply the IGBT's with a PWM signal, but this will also pass all the internal protections. Or find a heater that is originally PWM controlled. I just found such one; Search Ebay for "3M51-18K463-FB". Starting at € 10,-

[johu]

Not bad, worth giving a shot!

[FJ3422]

If you need some dimensions for checking fitment, let me know.

[arber333]

Tested the heater today. I basically placed right before the input of the cabin heater. So it's inverter -> motor -> pump -> heater -> cabin -> inverter. To my dismay everything got warm except the cabin. It doesn't seem like the radiator extracts a whole lot of heat from the water even with the fan turned half way up. Is that normal?

So I think I will try the PTC route next. Apparently the Diesel version of Touran has a slot in PTC element (part number 5Q0963235A)
https://www.ebay.de/itm/Elektrischer-Zu ... 3449719000

Only problem there: my DC/DC converter only sports 750W so I either need a larger one or derate the heater. I think it has CAN control anyway.

EDIT: I could also create a loop just for the cabin heater. So one more reservoir, one more pump. How does that sound?

You could have a control switch (thermostat) inside cabin that switches coolant flow towards internal heat matrix. Those open only at 80deg which is too hot for EV use. Or you have the cloged up matrix. Grease from the coolant can form clogs in the matrix because there is some threaded rod inside those pipes which increases flow time through heater. Nasty stuff, better to just replace the matrix...

I like those PTC heaters and i think if you have the space and the will you are better off using one. Sadly my 406 model does not have space for the aux heater, otherwise i would install it long ago.

Do you by any chance need DCDC from Ampera? I will go Outlander charger/DCDC route and i will soon take the Ampera DCDC out. I will got for wholy liquid cooled electronics. It is 1,8kW unit commanded by single 12V enable and CAN signal. It is air cooled and it is not IP65 rated though. I am running EHPAS pump, Vacuum pump, all lighting and electronics and i dont see 14V go above 50A. I use 2x 12V 4000rpm fans directly on the ribs and they are adequate. If you take the DCDC you get them too.

A

[johu]

If you need some dimensions for checking fitment, let me know.

Yes that would be good, just HxWxD. Thanks

You could have a control switch (thermostat) inside cabin that switches coolant flow towards internal heat matrix. Those open only at 80deg which is too hot for EV use. Or you have the cloged up matrix. Grease from the coolant can form clogs in the matrix because there is some threaded rod inside those pipes which increases flow time through heater. Nasty stuff, better to just replace the matrix...

I think not, I can hear the pump moan if I turn off climate control, which apparently closes the heater valve. And then it runs a lot lighter with climate control on. But who knows what happens, it doesn't really work anyway.

Do you by any chance need DCDC from Ampera? I will go Outlander charger/DCDC route and i will soon take the Ampera DCDC out. I will got for wholy liquid cooled electronics. It is 1,8kW unit commanded by single 12V enable and CAN signal. It is air cooled and it is not IP65 rated though. I am running EHPAS pump, Vacuum pump, all lighting and electronics and i dont see 14V go above 50A. I use 2x 12V 4000rpm fans directly on the ribs and they are adequate. If you take the DCDC you get them too.

Hmm, that sounds very tempting. Do you have some dimensions? Would be nice if it fitted into the original battery box. But could also go on top of the inverter, it is pretty dry up there since I blocked the air inlets.

[arber333]

Hmm, that sounds very tempting. Do you have some dimensions? Would be nice if it fitted into the original battery box. But could also go on top of the inverter, it is pretty dry up there since I blocked the air inlets.

Here is all data regarding this device...
https://leafdriveblog.files.wordpress.c ... _2014.docx
Seems like it is about 13” X 9” X 3.5” which translates to 330mm x 230mm x 90mm
i took the plastic duct off and i am using 2x 12V fans at 4000rpm. Air flow suffices for most uses.

Pinout
https://leafdriveblog.wordpress.com/201 ... dc-or-apu/

Mounting inside 406
https://leafdriveblog.wordpress.com/201 ... taza-dcdc/

[johu]

Just went outside and measured, it is about as wide as the inverter and about as high as my white junction box, so it would fit nicely. Will see how far I get with the 750W or rather 500W (left over after lights, fan and misc). Then will let you know

I have the Volvo PTC here now, what sort of PWM does it need? Amplitude, frequency?

EDIT: Arber, I really think you have a point with the thermostat. I heated the water for 30 minutes yesterday and left the fan running at medium speed with air recirculation. Everything was hot but the inside of the car wasn't. Maybe water is bypassed rather than blocked.

[johu]

Argh! So Mr. Supersmart here had removed a climate control servo some months back because it was noisy. I thought it was just for A/C but in reality it controlled air flow via heater matrix or not! By default it is set to NOT flow via the matrix. So put servo back in and now I get warm air from the vents. So will give the water heater a second chance.
Will put a small PWM circuit in the white junction box and hook it up to a Schuko socket, so I can either plug the heater into that or the wall.

[MattsAwesomeStuff]

So Mr. Supersmart here had removed a climate control servo some months back because it was noisy.

Yeah, all this "warm air" flowing sure is an earsore. That'll fix it!