Max. speed in EV mode, 10 MPH ??

From a quick ctrl+f, I didn't see acceleration rate mentioned here. If you accelerate too quickly (even when warmed up), you'll be kicked out of EV mode. I imagine this is a safety feature.

 

I imagine that it is a battery power limit. Hard acceleration requires substantial power, but the battery can supply at most 36 HP. The engine adds another 98 HP.

 

Didn't they slightly revise something in the newest model that would impact this speed? That said Matt H says he has a 2012 Aqua.

Other than that my understanding is the same - the relationship between MG1, MG2 and the ICE should mean the limit is the same for all of us, give or take only the amount of error in the speedometer display which I guess could be different in different markets.

For me - 76 km/h (47.2 mph) on the display can be achieved without the ICE on. 77 km/h (47.8 mph) on the display cannot be achieved without the ICE on. The SoC and Engine temp don't enter into it - this is a hard and fast rule - at some point before the speedo hits 77 km/h, the ICE will come on if it isn't already.

 

I've only got a gen2 (clicked on the "C" subform by accident), but I'm pretty sure I understand the reasons for what might seem like excessive limitations on the (button) EV mode. First let me summarize the conditions (collected from several post so I hope I've got it right).

Prius gen2 from many countries other than the US have an EV button as standard equipment. As with the "C" the Australian gen 2 has a speed limited (button) EV mode of 28 MPH max (just a little higher than the "C"s 25 MPH). My gen 2 EV button is not low temperature limited, but it is high temp limited (pack temp about 104F max) and low SOC limited (EV unavailable if the pack is too hot or if it has too lower state of charge).

The dilemma with providing an EV button on the gen 2 was the trade off between its obvious usefulness and the fact that, when used inadvisedly, it can have a punishing effect on both the engine and the battery pack. Let me explain why.

Firstly be aware that when the engine is cold (the cats cold in particular) that the prius tries as much as possible to use electric motive power in preference to the internal combustion engine (ICE). This situation usually only lasts for the first minute or two after the engine starts. Ideally this warm up should happen while you're maneuvering out of your car park and/or local streets, where it's not much stress on the battery. When people use EV mode to forestall this warm up, then they often end up with a stone cold engine right at the entrance to the freeway or similar. Here the battery will struggle as much as possible to provide the acceleration, but often the ICE will be forced to work pretty hard straight from cold as well.

The various speed limits are basically for the following reasons.

1. Cold = No EV.
It wants that engine warmed as soon as possible. It's basically trying to get in early, before you need to hammer it. It would of course be better if you had the choice. Like if you knew you were taking a long drive then let it warm, but if you're just moving a few car parking spaces then use EV. Unfortunately they cant rely on people to have this level of common sense, because in general they simply don't.

2. Mild Cold = Limited 10 MPH EV.
It wants to let you do minor things like move around a car park or change car parking spaces, but it's also trying to ensure that you do need to kick off the ICE before you finish traveling any local roads and hit a freeway or whatever.

3. Engine in acceptable operation temperature range = "Full" EV.
It's still speed limited here, merely because it's trying to limit the total amount of EV power you use, and hence limit the consequent increase in battery cycling which shortens it's lifespan.

I hope that helps.

 

Double post.

 

i gave up on pushing the EV button because i found that in ECO mode it can keep the ICE off anyway even when engine is cold IF for instance I make sure the A/C is OFF (AUTO is off and REC is off, all OFF). then the ICE doesnt kick on for a full block away or so. i dont have time to test every single permutation of this though.

 

It does help. I wonder if having an electric engine block heater on your to warm up the engine would help? But otherwise I agree. I let the computer do it job and provide the best conditions possible for the engine and I (most of the time.)

 

You are right the button is worthless. I have tried to use it to drive the last little bit before getting home and it usually says it cant do for some reason. It would be much better if they used the extra button to disable the traction control if you get stuck. or some other feature, something you can actually use.