EV mod & Block Heater

[VaPrius]

I've only had my Prius for 4 weeks and I currently get around 48MPG except this week is coming in at 45MPG. We've had temps in the mid eighties so far but two days ago the tempature dropped to the mid thirties. Generally speaking, our temps rarely get into the twenties. I drive about 73% highway (65MPH) and my city driving is actually suburban.

Suburban driving:
- the speed limit is anywhere between 35 and 55 MPH,
- the only timed lights are those that turn on at night and off during the day;
- turn signal? what's that?
- if the other car can stop in time, then its okay to do...

[efusco]

Originally posted by VaPrius@Nov 19 2005, 03:13 PM
I've only had my Prius for 4 weeks and I currently get around 48MPG except this week is coming in at 45MPG.  We've had temps in the mid eighties so far but two days ago the tempature dropped to the mid thirties.  Generally speaking, our temps rarely get into the twenties.  I drive about 73% highway (65MPH) and my city driving is actually suburban. 

Suburban driving:
- the speed limit is anywhere between 35 and 55 MPH,
- the only timed lights are those that turn on at night and off during the day;
- turn signal? what's that?   
- if the other car can stop in time, then its okay to do... 

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You know, this just can't be answered with a simple yes or no. A lot depends upon how much time/effort/energy you're willing to put into improving mileage.

The EV button will not, unless used in very specific situations which you certainly are not yet at a point to recognize will only lead to lower mileage. Clearly it's not an easy solution for you.

The EBH has the potential to improve your mileage in the first few minutes of use and give you heat faster...particularly if you usually park outside. But whether this will lead to long term improvement in fuel economy is no clear and likely depends upon the distance of your drives and how often you'll be able to plug in (ie at work/school as well as at home?). There's a thread under "performance improvments" that's some 9 pages long discussing the EBH, you really should read that. There are innumerable threads on the EV button.

[hdrygas]

I would agree the EV switch has less utility, I have to say that I mainly use it to show off. I think that it may have some utility in driving in to a parking place where you know the car will be left long enough to cool off and need to run the ICE to warm up for a while and you can take advantage of that to recharge the battery. Others may chime in on other uses. The block heater however with a timer, will add to your milage from the git go. Having said that learning to drive the car will do more than either.

[AlphaTeam]

I work at a school that has a large campus. I might drive .25 - .5 miles one way from building to building. I'll stay a while and go to my building.

Would it help me to have one? I'm thinking I could go EV from building to building and not have to warm my engine for the short trip only to have it cool before I leave.

[efusco]

Originally posted by AlphaTeam@Nov 20 2005, 11:33 PM
I work at a school that has a large campus. I might drive .25 - .5 miles one way from building to building. I'll stay a while and go to my building.

Would it help me to have one? I'm thinking I could go EV from building to building and not have to warm my engine for the short trip only to have it cool before I leave.

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1/4-1/2 mile and you drive on campus? Ok, your choice but seems like well within walking distance to me.

But, yes, an EV button would probably serve you well for distances that short. You would probably be limited to only 1-2 of those trips without a start-up to recharge, but if you only do it once a day it would be useful and fuel economical.

[daniel]

My reply to your original question depends on what you mean by "worth it." Do you mean, would the cost of installation be paid off in savings on gas? Or do you mean, would the bother be worth the cool factor?

I have no experience of the block heater. Even in Fargo the car starts fine at 30 below zero without it. (At 40 below, I stay home!) I'd trust what other folks say about the gas savings with it.

I do have experience of the EV switch, having been the first person on PriusChat to install the Costal version of it.

I'd advise against using it for that 1/2-mile drive. The reason is that you will discharge your battery so low that the engine will burn that much more gas recharging it. And since the car runs mostly electric (even with the engine running) during the first minute or so, your next 1/2 mile drive will burn more gas without putting much, or any, charge back in.

In my opinion, the situations when the EV switch are really helpful are when the engine is warm but will not shut off because traffic conditions have not allowed you to stop for the requisite 10 seconds to get into Stage 4 operation. Then if the battery is well-charged (six bars or more) and you are going under 34 mph and steady, you can engage EV until you are down to 5 bars. Also, if you are going slow speed (25 mph and under) AND the battery is 6 bars or over AND the instantaneous mpg is low (20's or 30's) you can engage EV.

Also it's nice for the cool factor: shut the engine off in parking lots to spook and impress pedestrians. (DRIVE VERY CAREFULLY IF YOU DO THIS BECAUSE THEY WON'T HEAR YOU!)

I think the EV switch was very much worth it for me when I lived in Fargo: Small town, short drives, often did not get into S4 operation, lots of cold weather, so the heater frequently prevented the engine from shutting off when it really should have, etc.

The other situation when the EV is worth it is if you are going to move the car a very short distance. It will go half a mile in EV, I just don't think it's efficient to do so. But a block or two, or less, is another matter. (Though even then, I'd use EV only if the engine is COLD. If you drove it in the last few hours, and you are going to drive several blocks, I'd use the engine.)

But in any case, for a gadget freak like me, the EV switch is definitely worth the cool factor! Read the articles in the Knowledge Base. I'd recommend Evan's method using a real switch if you are comfortable taking apart that much of the car, or the Costal switch otherwise. The light-flasher switch has some undesireable side-effects, such as causing your brights to flash when you engage or disengage EV with the headlights on, and preventing the flasher from working if the lights are off. In my view, these are unacceptable.

[AlphaTeam]

Originally posted by efusco@Nov 21 2005, 09:14 AM
1/4-1/2 mile and you drive on campus?  Ok, your choice but seems like well within walking distance to me.

But, yes, an EV button would probably serve you well for distances that short.  You would probably be limited to only 1-2 of those trips without a start-up to recharge, but if you only do it once a day it would be useful and fuel economical.

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Ok maybe a bit longer. I do walk them in the summer and when I can, they don't pay mileage on campus. It is very flat and open. In the winter it will get really nasty with the wind. Also I haul computers and such from time to time.