CHAdeMO Relay Hack, Switch, and Testing

by Ben N on November 11, 2021

Continuing work on my CHAdeMO Vehicle to Home project...

On the Mitsubishi iMiEV electric car, it’s totally possible to activate power to the CHAdeMO port WITHOUT needing to use CAN bus signals. It can be done completely analog, with just a few simple 12V signals.

Part of the reason why is that the relay which controls part of the circuit to the battery contactors is easily accessible. This car has a few electronic components under the back seat. By removing the seat and protective cover, a person can easily get to the relay.

Jumpering the white and blue wires of the relay connector feeds 12V positive power to the one side of the battery contactors. Earlier, I had tested jumpering this, and it worked! The car needs to be in the ON setting to provide the power.

Now, I would instead add a switch. I simply connected some solder-less male spade connectors onto a length of 2 conductor cable, and inserted them into the correct ports on the relay connector.

I routed the cable up to the front of the car and under the dashboard. On the left-hand side, there’s two unused switch locations. I popped out the blank plates and set to work modifying one.

I have some light-up 12V switches which have an external diameter of about 7/8ths of an inch. I drilled that hole size through the blank plate and Dremeled-out just a bit more as needed for the switch. Then the switch popped right into place.

On the back of the switch is three connections. Two are for the switched signal and the third is for ground, which is needed for powering the light on the switch. I connected the two wires from the relay to the main connections. I found a bolt under the dashboard that would make a good ground connection. I added a ring terminal to the end of a piece of green wire and connected it from the switch to ground.

I now had a switch which would light up when sending power to the positive side of the battery contactors.

12V light-up switch.

To complete the circuit to run power OUT through CHAdeMO, pin 10 in the CHAdeMO needs to be grounded. I have that pin wired to go back to a switch and then to a ground. So, if I turn on the car, I then need to flip the switch for Pin 10 to ground AND flip the switch on the dashboard to ON and see the red LED light-up. Frankly, I could turn on the two switches in either order, but by flipping the dashboard light second, and seeing the light come on, makes that light a very good indicator of the HIGH VOLTAGE being on at the CHAdeMO port.

I could even wire things up so that Pin 10 was hard-wired straight to a ground, and then I would only have to flip on a single switch. However, since this is all just experimental and HIGH VOLTAGE, having two switches and making things very intentional seems like a safer approach for the moment.

I plan to connect power from the CHAdeMO port to a Hybrid Solar Inverter. I was able to purchase a SolarCity H6 inverter relatively cheap. This inverter supports on and off-grid setups and high-voltage solar and batteries. Unfortunately, it’s “orphaned”, and has no warranty or tech support. (But that DOES make it affordable!)

I believe that I can run my battery power in through the Photovoltaic input and create 120/240VAC split-phase off-grid power. However, I need to run a few testing experiments first and make sure to do things safely, including adding fuses and a pre-charge circuit.

That’s it for now!
Until next time, stay charged up!
-Ben Nelson

PS: I also played around with a UV-activated resin! It’s like two-part epoxy only it’s just a single liquid you can brush on. Then you set it in the sun and the UV light cures it solid in just a few minutes. I tested it on a scrap 3D print which was made from the same type of plastic as the handle of the CHAdeMO connector. I plan to use this as a sealant for the handle. Should make it stronger and waterproof.

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