In the future could you label things by color in the graph?
I think I get it, but It took a while to figure out.

Green =
Red =
Blue =

and so on.

So are you saying you went to EV mode in about 86 seconds when using the block heater? I'm really curious what this would be like on a 0 degree night.
You could get similar results, but will probably have to pay for more energy to run the block heater for more hours in winter. Don't you think?

So I can imagine the gas savings.
What about the cost savings?
CO2 savings if you consider the power plant?

Thanks for doing an experiment I've always wanted to do.
( But I still don't have a block heater, but think I can get one for about $120. ) OTOH, how much gas would I need to save to get my $120 bucks back! Catch-22 as they say. ( I know they say that, but I don't even know what catch-22 comes from! )

Thanks for posting.
-John