Whats the wisest way to Use the EV switch?

It does no harm leaving a nimh battery low overnight. This is a problem with lead acid batteries.

The reasion for leaving it low is that the recharge for some of us is basically free, since the car runs to heat up and the same amount of fuel can sometimes do both. All depends on conditions where you are driving first thing in the morning.

Only time you should worry leaving it low is if you are storing the car for 6 months or something.

There could be extra wear from running it far up and down more with a EV button, but the car does a pretty good job of covering the range the EV does even without the button.

I always get to 2 pink bars if I park with AC going. And Green bars regularly in winter. EV works within this range and I rarely get it to go up or down more than 2 bars.

 

In city traffic I get horrible gas milage when the Prius is warming u (since I can't control the speed and have to stop at redlights). I hate that screen when it shows the engine runnning and no power to the wheel but power to charging the battery ARGH! I get it evey mornig when it's cold and I'm standing still. There is now way I can avoid this but at least as can make sure that as much of it as possible goes to recharging the battery so I try to leave my Prius on low battery whenever possible as I know I will charge 1-3 bars as soon as I run it in cold weather. I don't have experience in Warm weather and that might change my habit.

 

There's no theory needed here. It is quite obvious if you watch your fuel flow during warm up.
By the same token even if I don't discharge the battery I can drive at 10 mph or 30 mph burning about the same gasoline. The Prius pours on the extra for warm up and if you choose not to use it it gets wasted somewhere.

So my commute I have to start out slow and because if this I rarely get a 5 minute bar starting out over 25 mpg whether I ran the battery down or not. If I am able to start out a bit faster my mpg is more like 35 for the first 5 minutes.

There is no drop in mpg from the battery charging during this kind of warm up period, plus the car warms faster so it gets to normal mpg quicker.

 

The problem with using EV exclusively for the first mile or so is that in EV mode you have to drive with a feather-touch. Since the Prius was not designed to be a pure EV, it does not have the power in EV for normal driving. Accelerating that slowly is rude to the drivers behind you.

I find that in extreme cold weather (as when I lived in Fargo) if the SOC was at 6 bars in the evening, it would become all green and stay that way a long time before it was warm in the morning. Since it is going to run for a long time, might as well charge the battery from a low starting point. And since I cannot drive in a courteous manner in EV mode the only option is to drain it in the evening.

Note that even at 2 bars, where the car starts the engine, the battery is far from discharged. The Prius just does not let the battery get very low.

Further, my method for drawing down the battery is not to drive entirely in EV. I use EV only at slow steady speeds. I start the engine to accelerate from a stop (which is more efficient than EV, and more courteous to drivers behind me) and then engage EV once I'm up to speed. I aim for around 4 bars at night, not the minimum 2. Drawing down the battery with this intermittant method is far more efficient than a mile of pure EV, because accelerating on EV is inefficient.

Otherwise I use EV much as Evan does: if the SOC is 6 bars or above, AND speed is slow, without acceleration, AND the MFD shows low instantaneous mpg, then and only then do I engage EV, disengaging it when the SOC drops below 6 bars. Also I use it in parking lots and during very slow or slow-and-go traffic conditions, and sometimes coming up to a traffic light if the engine does not stop on its own (i.e., if it's not quite warm yet.)

I never use EV for long periods. Essentially, I try to immitate how the car itself uses EV. Once the car is warmed up I seldom need to, other than getting it down to 4 bars on my last drive of the day (which is often my only drive of the day). And parking lots. I love to glide along noiselessly in parking lots.

 

Not an option for me. Too cold in the morning to use any EV. At least till spring.

 

I certainly am talking about "switched" EV. And the colder it is, the more touchy it is. In the heart of a North Dakota winter it is almost impossible to prevent the engine from kicking in, probably because the cold battery is so much less efficient.

But even here in Spokane, it is inefficient to accelerate in EV mode. It therefore makes more sense to accelerate using the engine, and for that reason, the end of the drive is the better time to deplete the battery, if one is going to do that.

 

I sometimes use it for stop-n-go traffic, when I'd like to accelerate
a *little* harder than the system will tolerate without lighting
the ICE when the line moves up during a light cycle or whatever.
Very occasionally I'll use it on the last bits of arriving home,
when I notice that the coolant temp has dropped and I see no reason
to add more heat to it to get another 50 feet toward the driveway.
.
The idea of using EV to reach a low SOC when you know there's a long
downhill ahead is also quite valid; leaves more room to capture that
potential energy from the descent into the battery. That's a net
gain despite all the various conversion inefficiencies in the path.
.
Other than that, I mostly let the system do its own thing. Especially
when the pack is cold and it'll only give me 40 or 50 amps either
way in the first place.
.
_H*

 

I can only add what I *plan* to use it for since I have neither the car nor the switch!

I often have to shuffle our cars around depending on several factors. Moving the EVs is a treat, but firing a cold ICE just to move it eight feet is like putting needles in my eye. Allowing the Prius to move in and out of the garage without firing the ICE will be my main use of the EV switch. Plus, when my friends start giving me grief, I'll use the button to pretend that my Prius is an EV too...

 

Question: I've been mostly away from the forum for a year or so but when I last frequented here there was concern regarding the possibility of warranty problems if one installed a second source EV switch. Has this issue been resolved?

I see where I can purchase an EV mod for $45 that uses one of the steering post stocks as the switch. I want one. So .. What's the deal.

 

When the battery is cold it cannot deliver as many amps. In EV mode, the harder you press the pedal, the more amps the battery must deliver. If it cannot meet the demand, the ICE will start.

 

This has been a great thread. I have the Coastal EV kit in my shed. Of course, the weather was lousy snow & cold after I got , as my wife calls it, Baby, last Friday. As soon as I get a little time and some not freezing weather, in it goes.

Thanks Windstrings & Dr E , et al