Another Weird Hybrid Ecu Behaviour

[King Crimson]

Went to mall the other day which is about an hour away from my home, after reaching the highway i was cruising at 80 km/h (50 mph) at some point i realise that the Battery is full, like completely full with all bars filled, i was really confused at that moment as i had never seen that happen. About a few seconds later there was a downhill section of the highway and with my Battery full i would expect that the Battery would provide power or at least the engine would be off but nope, the engine turned on and stayed at 1000 rpm's while i had my foot off the gas pedal my speed was increasing due to going downhil so i had to use the brake to maintain 80 as there are a lot of cameras there.

As soon as i slowed down and exited the highway everything turned back to normal and i used the battery all the way to the mall. At the time the ac was on at 24 celcius in eco and for the driving profile i was in normal mode, it was about 40 celcius that day so perhaps the battery didn't work because it had to cool down due to all of that energy that it recuperated? But then why would the engine turn on when i wasn't even pushing the gas pedal? 

[Devon Aygo]

If the Hybrid Battery is full and you continue to regenerate the car will "waste" the excess power by using a MG ( motor generator ) to turn the engine over, it has to loose the regenerated power as it cannot store it so it looses it as kinetic energy via the engine.

[Jiff]

Thank you Devon Aygo, I've had this happen a few times on Telegraph Hill near Teignmouth. I'd noticed the engine revs climbing but no power being generated. I thought it might be a type of engine breaking. What you say makes perfect sense. Strange I didn't see it mentioned in the manual, I reported it to Toyota as I thought it might be a fault, nobody seemed to know why but said it shouldn't be a problem

[AndrueC]

I once cycled to the top of Telegraph hill when I lived in Exeter. I was the only one from my class to make it to the top without having to rest.

I rather spoilt it at the top though because I was unable to keep the bike upright when stationary and fell off. It was ten minutes before I stand properly. And of course we all loved coming back down though the thought of merging at the bottom with us in the outside half now fills me with dread. Guess traffic was lighter in the 1970s.

Happy days :)

[Timmon]

Yes, Devon is a good place to charge your Hybrid Battery! I reached full and still had 3 minutes of freewheeling down hill, last time I was there. Doesn't happen where I live, very rarely see it even up to the last bar before full!