EV Mode Drains Battery Faster After Cancelled?

If the temp of the ICE is under 40 deg celsius the Prius will run the ICE in a 'Protected mode' which means it will sit at a constant 2000rpm till warm. This is to ensure minimum wear on a cold ICE. It will just contribute power by charging the battery and so because the power needed to keep moving is more than the ICE can produce at that RPM it continues to drain the battery. You will note the ICE revs sound remains constant till it has warmed up or the battery is depleted.

 

Yep! When the ice is warming up, it's not propelling the vehicle. It's charging the battery

 

It's not in EV mode, so the 25 MPH limit isn't active. It's in stealth mode and that allows up to 46 MPH, IIRC.

At some point the ICE will power the vehicle, but I'm not sure what the parameters are. You're not exceeding those limits based on your information and results.

 

OP was talking about pressing the EV button.

 

The Prius CVT gear box allocates ICE engine power on a 1/3, 2/3 ratio. This means always 2/3 of its power output is sent to the wheels and 1/3 to battery charging (MG1). So with the engine in warm up mode it will help propel and charge but only minimally as it is restricted to 2,000rpm till it is warmed up.
The ratio can move more in favour of charging (i.e. car stationery) but the max power to wheel contribution from the ICE is 2/3 of its total output.

 

I think he was taking about when the car exits EV mode due to max speed or low battery.

 

He was. He said that anytime he presses the EV button, it drains the battery until it gets to two bars and then acts normally.

 

Yes, but he said it kicks out of EV mode and he notices his battery still discharges. That's why we were
explaining the normal function during the warmup phase while driving.

 

Right... I said that... He presses the EV button... goes 10 mph, it kicks out... and then it runs the battery down quicker, until it gets to two bars...

 

In my experience, during warm up, a higher power demand or lack of battery power can force the car to use the ICE for propulsion instead of the battery. I'm not sure if this is recommended or not to do on purpose, but sometimes you have to accelerate onto the freeway with a cold engine, and the Prius makes that change to give you the appropriate power.

Still the high battery usage is normal during the warm up cycle. The battery can provide propulsion with a power demand past the middle Eco line, which is normally considered the max battery output. Doing so of course means dramatically faster battery drain. Forced EV mode and warm up mode both allow this higher battery output/drain than stealth mode does.

To test see what your max battery output actually is use forced EV mode with a warmed up engine and charged battery. Before reaching 25 mph slowly increase the power output into the ICE range and note where EV mode turns off because of 'excessive acceleration'.

 

The reason the battery drains faster is that although the battery gauge appears to be linear the actual power in the battery is not. If you imagine the available power in the battery as liquid in a jar the jar would be in the shape of a 'V' so there is more ompf at the top than the bottom. With more draw on it than supply what is left runs out quickly. When the ICE is warm it will rev faster and therefore contribute more to the propulsion of the vehicle meaning the battery won't drain but charge.

 

Yes! IIRC, the battery isn't being charge during the warmup cycle ???

 

It is but the amont of charge it receives is much less than the draw on it from the electric motor to move the car due to the low RPM of the ICE while it warms up.

 

Yes, that's correct.

 

I use my battery every time I come home in my neighborhood. I'm always in EV mode but not forced EV mode.. When I get home my battery is pretty much at the lowest level it can be. Am I hurting things by starting up the next day and using the ICE when it's still cold? It seems to act warmed up before I exit my neighborhood and I can coax it into using some battery power before I hit the highway (again, not using the EV button, just throttling back, then staying under the 1/2 way mark). I noticed the rapid battery drain too initially and it sort of worried me. But I have started using the display on my Navi screen that shows trip information. On the right hand side it shows MPG use in real time. I find that quite a bit more often I am using battery only even if the "EV" icon is not present on the upper screen. Using that screen in place of a scangauge has helped me to better learn how the car works in its different cycles of use for a trip. Now I'm worried that I may be hurting my ICE because the battery is depleted so much prior to the warm up phase.. But during the warm up phase the car seems to drain the battery to nil first anyway (just to buy itself some time to warm up perhaps?) so I can't see how it's too hard on the car.. It's not like I'm flooring it either.

 

It does depend on how hard you accelerate. The car cant be sure your arent accelerating harder to a void a collision so it will over ride all this warmup stuff if it senses it had to to get you out of trouble

 

That's always fun. I've gotten the green arc to fill all the way up to just below the PWR bar with the forced EV mode. I invoke the EV button if I know I will be creeping in/out of a lot, but with a warm/hot engine, I may use it if, for example, I need to finish cresting a hill at slow speeds and then I regen the long way down on the other side.