I saw the "EV" mode somewhere, I think it was an xgauge or something, was interesting but didn't dig into it.
That's really interesting that you have to come up to temp *and* completely stop for the engine to turn off. I was wondering why sometimes it seemed like the engine didn't shut off even though it should. That's some weird programming I'd say, sounds like the ev mode button is right up my alley. I build harnesses, so fair chance I have the terminals to add to connectors if needed, or if I can source the connectors, shouldn't be hard to make a T adapter.
Having the ability to turn off the engine would be nice. Now the question is how to force it to stay on with out wasting power. Maybe I could tap into the AC controls and send the signal to the ECU that the AC needs to be on, and have a relay or something that would open connection, so the actual AC pump doesn't kick on, but when in "normal" use the connection is together so the HVAC controls work like stock.
Example case of where that would be useful is if you're going say 35mph in town and battery is charged so it wants to use EV mode, but you know you're going to be driving 55mph+ shortly, you don't want it trying to recharge the battery while at the higher speeds.
It would be really nice to control when it does the recharge too.
I've played a tiny bit with the "B" mode. Is the only benefit to that mode more regen? It does slow the car down faster, so right at the end of the coast a "B" mode "brake" might regen more than the brakes would do? I suspect the effect is tiny overall but an interesting concept at least.
Anyway, I scanned over the Toyota hybrid system wire diagram and engine control and didn't see any switches that sounded anything close to an EV mode. I'm pretty sure these wire diagrams are world wide, I've at least seen notes in them for Fed, California, Canada, and Brazil for different vehicles. I tried to google for the ev mode but not a whole lot came up, just some people mentioning a kit and people taking about using it.
Just found this when looking for a kit, site looks old and some links are broken. There's no instructions sadly.
https://www.autobeyours.com/EV%20But...or%20Prius.htm
Oh found another page on the site with instructions it looks like.
https://www.autobeyours.com/EV.htm
I'm pretty sure I have those terminals on hand! Sounds like it's just a wire to ground, so should be simple to wire up. I checked my wire diagrams and checked a few different points and it looks like the ones I have don't have the EV mode wire in the diagram. I haven't quite figured out the exact coverage for those diagrams, I thought they were likely world wide, but clearly the EV mode pin is missing so it's not world wide, maybe North America, or Western world (North + South America).
Small update for the thread, I messed around driving up down a bit for family today, yard sale and such, and reset my trip at my parent's house and went 70mph on the highway to show them the mpg drop at those speeds and noise levels and such. Round trip with a couple stops it indicated 50mpg. Down to 2 bars on the gas gauge, probably should have filled up on the way home, but instead of taking the express way, I took the back way like I normally do from that part of town which doesn't really have a good gas station to fill up at. Should be interesting to see how the mpg compares to the rough average of what I've seen seeing on the screen, and the whole bladder tank think.
Also, I just picked up a small trailer for $80. Decking isn't anything special, but it looks like it will work well for the prius if I need to haul something too big for the car, but small enough a truck isn't needed. Makes me want to design it so it's somewhat part of the boat tail shape to offset the extra drag. Either case, I've been needing a small light duty trailer for a while, the 15,100lb rated equipment trailer is a bit overkill for most things and is around a 25% drop in mpg for my diesel when empty.