A similar question has probably been asked before but I was not able to find: Do you know if there is any way to tell the HPWC to stop charging, based on an electric signal (e.g. 0-5V or 0-12V)? Here is the long explanation of why I need that: Here in Quebec, we are in the special situation where: 1) 99% of the electricity is hydro power (i.e. easily interruptible, no need for the utility to encourage people using electricity during fixed hours at night, and 2) >70% of homes are heated by electricity, which means that Hydro-Quebec needs to import power when its very cold (typically below -25 C/-10 F). For that reason, they offer a special rate that is half price when temperature is above -12 C/10 F (so most of the time), and is about 3 times more expensive when below that temperature. And obviously, the transition does not occur at fixed times. In Montreal, the high-rate period occurs about 300 h per winter (the equivalent of 14 days, 24 hours a day; each period can last anywhere between a few hours and a few days nonstop). To be able to apply, you need to have another source of heating installed in your home, that switches on automatically, based on a signal (probably 0-5V or 0-12 V, or something like that, I have to figure it out). It also cuts the water heater power, but you have a special button if you want to heat your water anyway. I'm planning to apply for this rate (keep my old oil furnace for peak hours, and have a heat pump/AC for the rest of the year). Now the car. Four solutions came to my mind so far: 1) Manually plan and charge only when the weather forecasts indicate that the temperature won't go down too much (or at least not before charging is finished). Not very practical: I would have to check each time if I need to limit the charge level in order to make sure it stops charging before the temperature is predicted to go below -12C. But that's what I plan to do right now. 2) Put the HPWC on a switch similar to the water heater, so I have a button to charge anyway if needed. Not sure however if the car would appreciate suffering power cuts on a regular basis. Probably not good. What do you think? 3) Similarly, if possible, send the signal directly to the HPWC so it gracefully stops charging. Hence my question at the beginning of the post. I'm not sure the car would appreciate that either, but maybe there are special communications between the car and the HPWC so the car doesn't interpret that as a power failure? Do you know if the HPWCs offer such possibility? A jumper or something? I can adapt the signal. 4) Have a computer that receives the peak-hour signal and sends a command to the car (via the API) to stop charging if it is charging, and start back charging when the signal goes away. This is somehow my preferred solution. (I already wrote some code in Python to communicate with the car. A RaspPi would probably do the job.) However, there is some security concerns about leaving a computer on with access to the car, and I would need to generate a new key every couple of weeks. But maybe I could turn on the computer only when needed. Any other suggestions?