Not specifically
to the MINI, but
for the MINI…
Today I finally modified my Grizzl-e EVSE to enable control by my home automation system.
Hat-tip to
@pictsidhe for
pointing me in the right direction earlier in this thread (more than two years ago!). A while back I found a post in the Ioniq 5 subreddit
discussing just such a mod to the Grizzl-e Classic, but pursuing a different home automation goal. In my case, I don't need a way to control the EVSE for a specific charging time window, but rather to disable charging when the outside temperature drops below a certain threshold.
Because I heat with a heat pump backed up by a natural gas furnace, I'm on a dual rate plan with my electric utility. Electricity costs 6¢/kWh (Canadian, taxes and fees included) most of the time, which is about 25% cheaper than the standard rate. Because most of Quebec heats with electricity, when the outside temperature drops below -12°C, to reduce demand, dual rate customers are switched to the backup heat source (furnace) and the electricity rate rockets to 40¢/kWh.
I already use a system of sensors and relays to limit the use of my 5000 W garage heater when it gets that cold, so I wanted to be able to disable charging my car without having to pay attention to the temperature and intervene manually.
Using the Reddit post as a guide, I found a Zigbee version of the same Chinese offbrand relay. I opened up the Grizzl-e and tried to find a source of 12V DC to feed the smart relay, with no luck. The same two pads on my v.2 Grizzl-e Smart's upgraded wifi board don't supply 12V, and I didn't want to poke around any further, so I found an old DC wall wart in a junk box and decided to put it to use. I was also wary of putting a ZigBee radio inside the EVSE's beefy aluminum enclosure and getting a reliable signal, so I decided to drill a 5 mm hole out the back of the case and mount the relay outside.
So far I've done a few tests using the Hubitat app to switch the EVSE on and off, and written two very simple routine pistons that will control it according to the temperature. At this point, it does indeed prevent or interrupt charging, but when the relay closes again, the EVSE returns to the ready ("vehicle detected") state but charging does not resume. I'm not really sure why. I've packed it in for today, but tomorrow I will test if there is some sort of countdown timer in the car when resuming after an interruption. I might also test it without the resistor.
Does anybody know if the SE is supposed to resume charging after an interruption? I thought that was default behavior. More testing in the morning.
