openinverter forum

Thank you. I'm in Toronto. And thanks to this thread and many other threads on this forum, I've established that I'll be using the Tesla LDU with the reverse oil pump. I'll get into more details in my own thread, but general thought is I'll also use some Chevy Volt gen 2 batteries and a Tesla charger with Damien's hack board. Haven't decided on the bms yet. Also haven't decided whether I want to build my own motor cradle or use the one that was used in this thread (that I see you also used in yours).

Again on the driveshafts, i'm assuming I'll use the ZeroEV Tesla stubs that mate up to Porsche 930 ends. And what I saw on Mitchy's thread for his 981 build, it's a 108mm PCD bolt pattern to attach the driveshafts to the stubs, but not sure if I can find some that are plug and play or whether I'll have to get something machined and welded.

I liked the bolt-in cradle from F1moto because it fit perfectly into my Boxster space and left lots of room for a battery pack. It also came with two (2) drive hub adapters that were welded to a shortened Tesla drive shaft. If you are putting the car on the track, I would go with a fully machined drive hub. If your car is a daily driver, a welded stub shaft (like mine) should be good. For BMS, look at the Orion2 for its flexibility. What controller are you looking at for CANbus?

Small update.

The EV conversion part of the car has been running great since upgrading the sine firmware to 5.20R. The update reminded me how fortunate the DIY community is to have the likes of Johannes developing and improving the crucial software element of the journey.


Otherwise, the woes concerning my lack of preventative mechanical maintenance continue. I’ve got a grumbling rear wheel bearing which is a hub-off jobbie (you’d never hear it with an ICE engine) and the OE power steering rack recently decided to exit this mortal coil, bleeding from the dust covers all over the habitual parking spaces I frequent. Brand new second hand rack going in this weekend.

My next update in the coming few weeks will be to reposition my charger and front HVJB into a horizontal position at the base of the front boot. I intend to make a false floor concealing everything, with the intention to completely hide any HV activity entirely.


A few weeks ago, we had an EV mini-meet at chez moi with Steve Knox and Janosch. Great to see the clipper cab and what a treat getting to drive it too https://www.clipper.cab/


Finally, I was a little downcast to read Jon Volk’s (Instagram @tesla_bimmer) recent news that he’s sold his E30 BMW. His energy, enthusiasm and skill-set for building a Tesla powered BMW was a huge inspiration for this build and I know it’s similar for others’ too. Along the way, Jon was willing to share his knowledge and experience for nothing in return - thank you! I guess all good things come to an end and I’m sure his next project will be even more tempting to follow.

Quick question. I will be finally updating my firmware from 4.85 to the most current version (5.20.R). Can I do it directly or should I update the firmware in steps (ie 4.95.R, then 5.10.R, etc.) I noticed you used a hex file and STM programming application connected directly to the board instead of the OTA firmware updates. Is this something you recommend for recent updates?

You can go directly to current version. I’ve found the OTA updates a little bit hit and miss, but that was partly caused by the memory on my esp WiFi module being full - you can avoid that situation by ensuring that you don’t rename the firmware or parameter files (when doing updates ensure the new files have the same names as the old ones). For instance, the firmware file name should be: stm32_sine.bin

viewtopic.php?t=2650

Update time:

Charger relocation

I have now moved my Tesla Gen 2 charger and front HVJB to sit horizontally in the front luggage compartment. There are several benefits for doing this versus my original arrangement:

1) There is a perfect size niche towards the rear of the Porsche 996 911 and 986 Boxster tub (RWD cars only) for the Tesla charger to fit, meaning the actual usable space that’s consumed by the charger is small

2) The weight will be lower down in the car

3) A false floor can bit fitted concealing all HV activity making it safer for inquisitive fingers

4) It’ll make the conversion look even more standard / OEM

To achieve this little project I needed to extend several low and high voltage wires. The low voltage wires were not an issue, but when it comes to the high voltage side, I tend not to like extending wires for fear of adding another failure point. However, the HV wires in question are just 6mm2 and therefore I’ve decided to use HV MC4-6 IP67 connectors rated at 30 amps. Of course, the circuit is fused. All HV cables are covered in protective conduit and where they terminate in screw terminals such as within the fuse holders, I have fitted conductive crimped ferrules to improve the fixing and reduce resistance (and any risk of heat build-up). As ever, all HV cables are clipped down every 100mm to prevent chafing.

The front HVJB could do with revising but I’ll save that for another day. Inside I have DC fuses for the charger, PTC heater and mini contactor for the same.


Before



During


After


In other news, the LDU inverter has been derating due to hitting TMPHS heat sink limit after about 20 miles of modest driving at 12-15 degrees C ambient. I’ve been scratching my head on what’s changed as the car had never done this previously, I’ve never had to run a radiator fan, should I? I wrongly convinced myself that must be the answer… so I proceeded to spend a half a day reinstating the Porsche OE rad pack fan, activated with a little bit of code (thanks Tom DB) via my Teensy VCU. So there I was, very pleased with myself that I’ve now got a working radiator fan and I proceeded to take the car for a spin. Annoyingly, with fan on full blast, it made little to no difference to the inverter temperature. [Head in hands]

That called for plan B: the issue has got to be a knackered water pump right? Well I very nearly went out and spent £200 on a new one, until I decided to inspect every bit of hose on the car. Occam’s razor. I found one of those little botches from three years ago that I promised myself to resolve properly when I next had time (when do you ever have time or even remember?). I’d fitted a 16mm internal diameter (ID) joiner on the inside of a 19mm ID coolant tube that I’d had to tighten down so hard with a jubilee clip (due to poor fitment) the joiner eventually deformed and collapsed over time. Coolant was barely flowing. 19mm joiner fitted and my inverter is now cooler than cool. Hallelujah.


Heated seats

The sport seats in my car were salvaged from a parts car two years ago and have heating elements and relays pre-installed. Wiring them up has been one of those jobs that I never got around to until recently. I followed this superb guide https://www.dennisvogel.com/heatedseats/ and really, it was just a case of buying the connectors, pinning them up and running wires. Very straightforward and satisfying job. OE Switches bought on eBay.

Homemade loom made up and integrated within existing harness, with 25amp fused feed taken from the main fuse panel (Porsche fuse A6)



Seat connector pinned up.


Before:


Rinse and repeat for passenger side.

Having heated seats is a must have in a conversion. Just wish I’d installed them sooner!

I admire the way you are always upgrading something on the car. I have a couple of questions:
1) I want to install a 12V inertia switch that will open the main & ignition contactors if there is a substantial impact. Can I power the Inertia switch from the Inverter 12V supply or should it be connected directly to the Main & Ignition 12V supply?
2) Where is the best place to mount the Inertia Switch?

2) Have a look where the airbag / ABS sensors of your car are mounted.

Boxster EV wrote: ↑Tue May 17, 2022 2:00 pm Well it’s been an interesting time of late… When I first completed the conversion give or take a few small issues, the car ran faultlessly for a year or so, which certainly led me into a false sense of security, as over the past four months it’s just been one challenge after another.

The biggest catastrophe was that my Chevy volt DCDC decided to let out the black smoke. I think it got a little damp during the winter months. I’ve since replaced it with an off-the-shelf IP67 rated unit (picture below) and relocated it nearer the HVJB for safety reasons. More seriously, when it ‘let go’, it sent a surge through the CAN BUS network taking out comms (CAN transceivers) to my VCU, ABS unit and gauge cluster. What joy!

Can you share the details of where you got the off-the-shelf DCDC unit?

Now that I finally got my motor spinning for the first time, I'm ready to get the HV batteries (same Chevy Volt type) and start sourcing these other components. Also seeing if there are any other options that work with the Volt bms in addition to SimpBMS. Not that I'm against using that one, just want to know what's available.

Thanks!

You are the second person I know who recently lost their DC/DC converter. The other DC/DC failure was it just stopped working. No smoke, no warning but just stopped reducing voltage. I'm starting to think that if they get too hot, they can fail sooner than later.

Thanks to the mods for updating my thread title. The car has now completed nearly 25,000 electrical miles running Openinverter savoir faire.


It’s also just passed it’s annual MOT.


The only real update is that I installed a DIY solar array at home to charge it.

Went through all the thread but didn't find anything about it: weher do you take of the brake preassure for regen by openinverter?

I think the ABS pump or other unit has it on canbus.
Time to grab a canbus dongle and find out.

modellfan wrote: ↑Mon Dec 11, 2023 1:32 pm Went through all the thread but didn't find anything about it: weher do you take of the brake preassure for regen by openinverter?

Prior to fitting an iBooster, I used an analogue pressure transducer on pot2 for brake pressure regen. However that’s now defunct since installing an iBooster. Today I only use very minimal ‘brakeregen’ setting with no CAN input from the iBooster or ABS system (ABS still works within the OE framework). Maybe one day I’ll look to revisit using CAN inputs, however that’s a low priority as it works well as-is.

A few updates:

I’ve been having trouble with my dash fuel gauge and have been putting off digging into the issue for some time. Bottom line is that I needed to open the cluster and repair a dry solder joint to the stepper motor and rewire. The next issue was that I was using a twisted pair of .5mm2 cable to run from my Teensy VCU (near the motor) to the easydriver board, however I am getting interference. Thanks to suggestions by Janosch and KnoxEV, it was identified that EMI was indeed disturbing the signals. I’ve now moved my VCU to the front of the car as far from the motor as possible. This has significantly improved things, but I still see small oscillations with the needle. Any suggestions out there on how to shield the Teensy VCU further would be most welcome.




Tesla Large Drive Unit coolant manifold delete:

This is a big deal. Ever since converting the car I’ve had concerns about coolant leaking past the infamous rotor seal. The length of this thread:

viewtopic.php?t=2242

demonstrates just how concerned others have been too. My OE Tesla seal leaked badly two years ago, with coolant making its way along the AC busbars to the inverter. It made a mess of my logic board, but luckily the inverter wasn’t damaged. I had several unsuccessful attempts at fitting Chinese replica Tesla seals and since then, I fitted a generic high quality SKF seal and Speedi sleeve which has been fine, however having covered more that 15k miles on this solution, I felt like I was living on borrowed time and don’t really want to ruin my drive unit. Therefore, I decided to delete the coolant manifold altogether.

To achieve this, I had two choices: modify my existing manifold which would take about a week at a machine shop or, buy a coolant blanking plate from one of the various US specialists that have developed this aftermarket solution (Tesla also do one but it’s not available to buy). I chose the second option. It was painfully expensive at nearly £650 once the importation fees were paid but it beats the cost of replacing the whole drive unit due to a catastrophic coolant leak. I can recoup some of that cost by selling my old manifold. It took about an hour to fit.

So far so good having covered about 1000 miles. Hoping that having a rotor that isn’t cooled doesn’t have any long-term issues. It’s worth the risk in my opinion (versus the alternative of a leaking seal). Noteworthy that forum user asavage is taking a more considered approach by placing a temperature sensor inside the rotor to monitor things.





New (to me) interior carpets

I replaced my interior carpet and door cards for newer versions in black rather than graphite grey or as the Germans call it ‘Dunkel Grey’. I need to finalise wrapping the centre console as that part is no longer available in black.



Relocate Power Steering pump

Next on the list is to relocate the power steering pump from the rear of the car and mount it behind the brake reservoir cowling from a left-hand drive car inside the frunk. A few positive for going this route: weight saving by removing all pipework that runs front to rear, weight distribution by having the pump in the front, but most importantly; mounting inside the sealed frunk to reduce the noise. I was going to have an electric power steering rack or column mounted / fabricated, but it would require too much cutting and modification to the factory set-up.





And that concludes the update on nearly 121k miles.

Boxster EV wrote: ↑Fri May 24, 2024 12:58 pm . . . forum user asavage is taking a more considered approach by placing a temperature sensor inside the rotor to monitor things

Last night was first trial run with "working -- with caveats" LDU Rotor Temp Monitor:


(sorry for the large view; can't resize a linked image here)

Rotor after a coolant delete modification (source):
Google says plain-ish steel blues in the high 500s°F (~300°C). The MLX90614 IR sensor I've installed can read up to 380°C (720°F).

Tesla Gen 1 ibooster installation:

Whilst I installed an ibooster a few years ago upgrading from a UP28 vacuum pump, I wanted to update this thread as I’ve improved the installation solution.

Here’s the first iteration whereby I offset the fluid reservoir position.

I was never happy with this solution, running hoses from reservoir to cylinder, however it was necessary as neither the Tesla or Porsche reservoir fitted when mounted directly – they were too high fouling the bonnet. Moreover, because the OE brake lines ran in front of the Ibooster the frunk cowling didn’t fit over it and made the whole thing look very ugly:


I haven’t changed how the ibooster is mounted (its straightforward as the bolt patterns make it almost plug n play for the Porsche).

Here’s a picture of the connection between ibooster and the Porsche OE rod to brake pedal. It is adjustable as the ibooster rest point must be within its calibrated parameters. I used blue Loctite to secure the adjustment bolts once tested and working.




Revised set-up

With this revised set-up I fitted the OE brake lines from the ABS pump to the cylinder from a later car that runs directly to the side of the brake cylinder. To overcome the reservoir fouling the bonnet when closed, I found some lower profile rubber seals that attached the reservoir directly to the cylinder. Look how clean the installation is compared with my first iteration.






For obvious reasons, power and ground cables must be properly installed and robust!


Final picture with the cowling refitted.

I did some research as I am also converting a 986. How deep did you dig into the fuel gauge? It seems like the fuel gauge is calculated by the resistance of the tank sensor and the "fuel consumed" CAN bus message sent by the motor controller. If they are out of order they can be recalibrated by PIWIS / DURAMATIC. Would mean you have to emulate the resistance and the can messages in paralell. Did you ever try this before resoldering?

For calibration:
The factory calibration procedure is to use 28 liters (7.3 US gallons), not 13 liters. It is also important that the fuel tank is completely empty before starting this procedure.

"Calibrating fuel level sensor system
1. Disconnect the battery and cover terminal or battery.
2. Remove cap over the fuel level sensor system.
3. Remove fuel level sensor. Removing and installing fuel pump.
4. Using a fuel extractor, completely drain the fuel tank through the fuel level sensor opening.
5. Make sure that the two recesses on the left and right hand sides of the tank are emptied completely.
6. Reinstall the fuel level sensor and, with "ignition off", fill the tank with exactly 28 liters of fuel.
7. Perform tank calibration with the Porsche System Tester 2 (PIWIS or Durametric):
- Select vehicle type (911 Carrera)
- Select control modules
- Select instrument cluster
- Select menu item "Tank calibration"
- Confirm calibration
8. The fuel level sensor system has now been calibrated."

One more question, are you using both coolers in the front or is one just enough?

modellfan wrote: ↑Sun Dec 15, 2024 9:07 pm One more question, are you using both coolers in the front or is one just enough?

I have a standalone easydriver sending signals from my VCU to power the stepper.

I’m only using one front radiator but on a hot day >30 degrees and many 7kw charges, that’s insufficient. Use both.