Since the electric heater with recirculation is now ready, I started working on the controls. The basis is a high voltage PTC element which generates more heat to the degree you cool it down. As a result most heat is being generated with the fan/blower at full speed. At Rick Donkers auto electrics I bought two four position switchs and connected it to the original levers.
The rotating switch did not survive the attempt. The sliding switch works fine.
However the bend cable is quite fragile and a continuous control would be better. Thanks to the suggestion of Erik I looked into PWM control like I do with the Pierburg pumps. Created a test setup for controlling the speed of a DC motor.
Worked very nice so I hooked up the blower instead of the small motor.
That made quite some noise. Erik proposed the solution by using another PWM freqency. Also added a mosfet to be able to handle bigger currents. And implemented the orginal fan switch. If you just slide the temp lever you get hot(ter) air. If you pull the original fan switch that gets overruled and you have two fan speeds.
Later I can configure how fast I want the blower to be at those two speeds.
I want to keep the original speedo but the fuel indicator and to less extend the temp meter are not that relevant anymore. Ingmar suggested to add a econometer. While I was into controls anyway I created a protoype. Hans gave me an old B20 temp indicator with the red scale. I transplanted that onto a fuel indicator and it works!
In case of high enery consumption for example when accelerating fast I can turn the needle towards red, center it during normal use and to the left when regenerating.
Documenting prototypes in schematics
I learned a lof from Erik (thanks!) about gate drivers, mosfets, input capacitance, creating schematics. It’s now all written down in TinyCAD.
And not only controlling the blower, remote controlled stationary heater, CAN-BUS module and temperature sensors.
Hesla at Cleantech Tomorrow
Earlier I heard about the Hesla, a Tesla with a hydrogen range externder in the below video (in Dutch) by Vincent Everts.
That did trigger some questions from my end.
But if the fuelcell is 75V and a max amperage of 256 A, then the power is 19,2 kW, right? If you run it for one hour it is 20 kWh?not 30 kWh? Assuming the DC/DC converter for creating 350V is highly efficient. The Hesla was at the Cleantech Tomorrow event in Teuge and I was able to check it out. Some of my questions were answered, but not all.
By the was, there was also an electric plane at the event.
Hesla update from Vincent
A new video has been added with some more information.
- How do they interact with the Tesla BMS?
- What about it’s registration? Currently it still is listed as a car driving on electricity. Does it still needs to be approved and will then hydrogen be added as a fuel? Similar to cars driving on pertol and LPG.
In the video it is mentioned that they do not touch the Tesla systems and that the Tesla warrenty remains in place. But how then do they get the energy into the Tesla batterypack? Perhaps I should get in touch with Holthausen to find out, very interesting.