openinverter forum

So since Touran has no built-in AC charger at all I created various hacky ChaDeMo chargers to still be able to charge it at home. For sake of completeness I will present the 3-phase version as well.
Power path: grid filter -> 3-phase rectifier -> buck stage -> output.
Let me walk you through this electric mayhem - again

Ingredients

• Metal enclosure that has to be lurking about in your basement (don't buy new)
• Heat sink (must also be left over from a previous project - EMW charger in my case)
• Fan (large 120mm from EMW charger)
• Rev2 or 3 inverter brain board
• Rev2 gate driver - half populated
• About 50A IGBT brick, 1200V! (in fact I use a 400A brick)
• 100A or so 3-phase diode rectifier (cheap as chips, these)
• an EMC grid filter (or your fuses will sing, also we want to be nice to the grid)
• Current sensor (here: half populated legacy sensor board)
• inductor (buck inductor from EMW charger)
• A 420µF film cap and a precharge resistor, discharge resistor (ooops, forgot about the latter)
• IC sockets (that are hot-glued to the Anderson connector to carry the ChaDeMo control signals)

Update: the IC sockets were bullshit, replaced them with a separate 7 pole connector left over from, guess what, the EMW charger.

Operation:

1. Plug in ChaDeMo (best do this first, as the output goes live as soon as you plug in - who needs an output relay )
2. Plug in mains, hit start
3. The cars battery relay is closed
4. The configured max charge current is transmitted via ChaDeMo
5. The current command from ChaDeMo is obeyed

I have no idea if the power factor is any good, but it runs fine at 9kW for prolonged time. I took it up to 11kW (28A battery). The fan is temperature controlled and has to go mighty quick (and noisy) to remove the heat. Bucking seems less efficient than boosting.

If you're interested I can upload the software to github. Works the same as the inverter software. Web interface, CAN mapping and all that. It's the same software as the 1-phase version.
But strong disclaimer: this charger is a mayhem, it offers multiple chances to be electrocuted - don't do this at home.

Hah, only do this at home if you ever did it before .

I see a need to chime in for some details.
1. If you will be bucking from 600Vdc 3ph rectified you will need at least 200A IGBT. Guess how i know...

2. It seems 3phase power factor is much nicer to a house than 1 phase, be it buck or boost.

3. Gimme code!!!!! And i see a need for special Wifi module interface just for charge application. Here you only need to set Volts and Amps.

Code is here: https://github.com/jsphuebner/stm32-charger

On the repo pin map :
Start input (PA2): start/stop charging

However PA2 is is the brake in signal on the normal inverter code and start is PB6. Has this changed for the charger or just a typo? Doesnt seem to be different in the code...

Oh see thats what I meant in another thread about redundancy
Of course the code is always right, start input remains on PB6

Rich man just blew a 400A IGBT brick. I connected it to a 22kW EVSE and already at the default setting of 28A DC the charger sounded a bit angry. I then set it to 32A and the charger shut off. It worked subsequently for another second and then died for good. Replaced the brick and it seems good again, will test at full power later.

I do wonder what caused the trouble. Maybe the grid at the EVSE had such low impedance that the control loop just didn't react appropriately to the little 3-phase dents. Also the failure mode of the IGBT is a bit unusual: it failed open. I tend to think that I lost the bond wires. Might open the module to check.

Take away: don't let your charger sound angry, it is telling you something

This reminds me of testing a gen 2 tesla charger on a 120v battery. Set to 3 amps...hmmm sounds weird. Lets try 10amps....BANG!

You guys are crazy. When it sounds angry, go lower, not higher.

johu wrote: ↑Sun Mar 07, 2021 12:34 pm Rich man just blew a 400A IGBT brick. I connected it to a 22kW EVSE and already at the default setting of 28A DC the charger sounded a bit angry. I then set it to 32A and the charger shut off. It worked subsequently for another second and then died for good. Replaced the brick and it seems good again, will test at full power later.

I do wonder what caused the trouble. Maybe the grid at the EVSE had such low impedance that the control loop just didn't react appropriately to the little 3-phase dents. Also the failure mode of the IGBT is a bit unusual: it failed open. I tend to think that I lost the bond wires. Might open the module to check.

Take away: don't let your charger sound angry, it is telling you something

Like i said Johannes, you want to have two contactors with charger in between. AC contactor on input and DC contactor on output. So whatever happens to the grid energy at shutdown will be small and usually IGBT will survive. I managed to run my buck charger that way for 6 years now. Also for good measure i add 100A output diode so HV battery + will never see IGBT.

In the beginning when i was using my first charger iterations i also used my own wound thoroid inductor. I am now convinced that was the cause of most failures. When i got Prius gen2 inductor i could run the air cooled charger at 18kW. I think that may be your solution. I think you have one at home. Give it a try...

mdrobnak wrote: ↑Sun Mar 07, 2021 5:41 pm You guys are crazy. When it sounds angry, go lower, not higher.

In the name of empirical science I have proven that again

arber333 wrote: ↑Sun Mar 07, 2021 6:15 pm Like i said Johannes, you want to have two contactors with charger in between
...
In the beginning when i was using my first charger iterations i also used my own wound thoroid inductor. I am now convinced that was the cause of most failures. When i got Prius gen2 inductor i could run the air cooled charger at 18kW. I think that may be your solution. I think you have one at home. Give it a try...

Yes, not having an output relay is negligent anyway, as the output goes live as soon as you plug in. Though I think this was not the failure mode here. You're probably right about the inductor, a larger inductance would filter out the gross current spikes that currently seem to be happening.

If in doubt, give it more power, it might not make the situation any better but will end the suspense.

Bigpie wrote: ↑Sun Mar 07, 2021 7:02 pm If in doubt, give it more power, it might not make the situation any better but will end the suspense.

LOL this explains a lot!

Mayhem reincarnation

BTW getting a synchronous (bidirectional) converter to run 0 current is not exactly trivial. Suddenly it starts sucking current from the battery and raises charger bus voltage above rectified mains. Then current suddenly swings back into the battery... Weird. Currently I just disable the power module when 0 current is requested.

I wondered about this yesterday after i watched your yt vid. Whats stoping the car pushing power backward into the grid and i guess the answer is some logic board but it is a worry that you could unwittingly damage the grid/the public socket you are connected.

No he cant hurt the grid. The bridge rectifier will prevent any feedback. Now I feel the need to make a Rich Man Gen3 version.

Ah yes thanks Damien, having two chademo cars this sort of thing is very appealing.

While it's charging at 10 kW I'm cooling it only with a 60 mm fan and it takes a few minutes before the fan starts operating.

Using a Tesla charger in the same way is less dangerous though, it also talks chademo

oh... somebody had asked about efficiency but now the question is gone... strange

What is the cheapest possible price for this build when the metal enclosure, heat sink, fan, caps and resistors are already existing?
Does this build also work with the cheaper https://openinverter.org/wiki/Mini_Mainboard ? The original post here is from 2020 and the Mini Mainboard brain board was released 1 year later.

Why asking: There are cheap cars (BMS charging 80 or 88 cells up to 4.1Volt) with ChaDeMo connectors that are been driven mainly by poor people. Many of those cars cant even charge on AC with 16A but only with 13A(of course single phase). People are charging those cars because of the lack of money on free ChaDeMo charging stations. They live in a tiny place without a garage, without a own parking place and so on and cant charge at home. Only charging at public stations is possible. Those free public ChaDeMo chargers get more and more rare. When charging on a free public AC charger is the only available solution at a region, the waiting time on a empty battery are many hours and the people have to sit and wait there in the car all those hours to be able to continue the drive.

The expensive solutions like for example https://www.setec-power.com/product/10k ... e-charger/ are financially out of reach. Such a charger cost more then the car the people are driving.
There is also sadly a not existing broken/free/'e-waste' ChaDeMo chargers market. The companies that are using such chargers always throw them away as e-waste. For example the nice 44kW Nissan ChaDeMo chargers that was famous about 12 years ago are now thrown away in functional state instead of giving them out for free. Reason for throwing out the ChaDeMo chargers and companies even paying other companies to 'get rid of them': CCS

So the only solution instead of waiting many hours inside of the car for poor people is to build this ChaDeMo charger from this thread and drive with it in the trunk to be able to use the free 22kW AC 3phase chargers with a self build Type2->CEE adapter to power the charger.
Thats why asking about the lowest possible price and hopefully a possible small size/weight.

Side question: Did some of you have a broken/used one that could be picked up and used for parts?

Yes, its known that the charger offers multiple chances to be electrocuted.

I am planning to buy/build a High Voltage (>=530V) 30kW CC CV 3-phase AC to DC charger. A response on my add in classified suggested to use a OEM Prius inverter with an openinverter control board for that. Adding ChaDeMo / V2G functionality would be a big plus. Has this been done by anybody, as a real 'poor man's big power ChaDeMo charger?

I was able to run this at 15 kW for 30 minutes then it overheated. When going above 15 kW a 22 kW EVSE will fault out after more or less time, probably because of some transient currents.

How much does it cost? Build one to find out!

A little bit off-topic, but in case there are CCS chargers in the region (here they get more and more), a CCS to ChaDeMo box could be an option. Would mean, to make a box with pretends to be a CCS vehicle (e.g. from viewtopic.php?p=37085#p37085) and pretends to be a chademo charger. Do we have already a thread to discuss this further?

Yes, it was indeed discussed quite a while back: viewtopic.php?t=1063

What about doing an 'openinverter special' project:
- a prius inverter
- a openinverter logic board
- a thirteen a dozen radiator, fan and pump
- multifunction inputs: 3-phase AC, HV DC, CCS, Chademo, V2G etc
- multifunction outputs: 3-phase AC, HV DC, CCS, Chademo, V2G etc
All in one garage style casing.

For people already driving an EV and interested in the openinverter platform but not planning to do a full blown EV conversion yet, this could be a great starters project. And a good way to promote openinverter to a broader public.