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Westfalia T3 with Chevy Bolt drivetrain

72280 Views 174 Replies 26 Participants Last post by  remy_martian
VW Vanagon T3 with Chevy Bolt drivetrain


I'm asking myself if DiyEcar is still the best place to put a build thread and to obtain help.
It was the case many years ago when the overvolted forklift motor was the rule, but now?

Well, my plan is to put a 200 hp 60 kWh Bolt drivetrain in a Westfalia... Exciting right?
Yes, but all the electronic and control in the Bolt fear me a bit.
Anyway, I will have the crached Bolt in few days and the West in few weeks.

Let me know if you have advice or help.


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So, a Chevy Bolt need a running A/C system to allow the CCS fast charge. The A/C system could be use to cool the battery temperature.
The DTC condition are:
-A/C Compressor motor voltage sensor circuit low voltage (need to plug the compressor to the 360V batt)
-A/C refrigerant charge low (need to connect the pressure sensors and fill the system with R-1234YF refrigerant)
-Cooling fan relay 1 control circuit (connect the 12V fan)

Well, I don't have the place and the desire to integrate evaporator and condensor for this system and my question is:
Is there any reason that a system with condensor and evaporator bypass/replace by a simple aluminum blocks with holes (represent in blue on pic) couldn't work?
The expension valves for the battery shiller and the cab (not on pic) will be in the system.


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I can't quite tell from that picture, but if I recall the Weber Auto YouTube videos correctly, the heat exchanger for the battery is supplied refrigerant from the A/C system after the cabin blower. If you plan on adding A/C to your vehicle you might as well use the cooling power to keep the battery happy.
It's exactly how the Bolt system work, but the battery heat exchanger (in center of the pic) is before the cabin. The battery coolant is cool down by the A/C.

My question is more related to an A/C system without condenser and evaporator.

I drive the Van since 6 weeks now without battery coolant and the cells stay closely match (3-4°C difference) at temperature between 20°C-33°C despite it summer here.
If I had the choice, I would not install the A/C system, but the Bolt system claim it in the fast charge initialization.
An heating system is way more important here with around 3/4 of year with temperature below 20°C (20°C to -30°C in fact).
No heat pump on this Bolt. Simply a separate heater in the battery cooling loop.
Any input about my A/C challenge (post 144)?
Matt, you fully understand my problem and my questions about A/C system.
I'd be more tempted to electronically fool the system than mechanically fool the system. If it's expecting a voltage, fake the voltage. If it's expecting a sensor, fake the result of the sensor. Should be doable with just some resistors.
Really, I would like to do that, but I don't know how to do that.
For me, mechanically fool the system is something I can do, but to electronically fool the system I would need help.
I slowly start to think that is possible to electrically fool the system.
Below are the schematic of the system in pdf.

The pressure sensors have those values:
5V - AC low ref : 11.5k
5V -Low pressure: 4.7k
AC low ref - Low pressure: 6.8k
I plan to put 0-10k potentiometers at the place of the pressure sensors and try to change the values.

About the compressor, I don't know how to fake the 360V input so my first idea is to connect the compressor to do a first test at the fast charge station.
If the compressor start I will simply stop the fast charge as my goal is to know if the fast charge work.


I tried a fast charge this weekend without success.
I put 10k potentiometers at the A/C pressure sensors place and connect the compressor/coolant pump/radiator fan to the system.
This permitted to clear all the DTC of the hybride powertrain control module, but despite that the car don't allow the fast charge to start.

Any tough?
Yes, the compressor was conneted. It don't started during the few first attemps of fast charge with the car turn off, but it started once with the car turn on (not sure if it start for car interior or for battery).
The result was the same in each situation: after 30 seconds of precharge (charger side) the car quit/refuse the session and everything stop.

Functioning hardware imply a fully functional A/C system with high pressure in the circuit.
The next step for me is maybe to try the idea of a partial, but pressurized A/C system (describe at post 144).
I don't have other idea...
It's probably partial success.
Before the hybrid powertrain module 2 shown DTC linked to the pressure sensor and now report no DTC.
Still, I don't know what to do as I don't know why this Chevy Bolt is not happy at the fastcharge station.
I've tested the van on a small road trip :)

Everything work well and this powertrain is awesome in the curvy mountain road.
150 kw and 58 kw of regen is :D
Still no fast charge, so it's a long and ''slow'' roadtrip with bigger days of just over 400 km. But there is a lot (still not enough) of J1772 station at any place and many are free.
More than 10 000 km of done here reaching arizona and we will add 4500 km to go home.
Details here:


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Re: VW Vanagon T3 with Chevy Bolt drivetrain

Great news Yabert! Congratulations. How long are you having to stop to charge?
A typical driving day was:
Full charge in the morning, drive 220 km, stop to charge 6h or 7h and drive another 200 km or so to the charge station for the night.
By chance we only did this 15-20 days during our two months trip.
The best days was: Full charge in the morning, drive 100 km, hike, drive 50, lunch, drive 50, hike, drive to the campground for a dinner and full the van overnight :D

A working fast charge is a must... I will work on this.

15 500 km trip without problem with the van.
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