EV Mod Question

Could someone please explain what the EV mod is.

 

non-north american prii have a button that allows you to operate the vehicle for low speeds/distances as an all-electric vehicle. the EV mod is simply adding this button (the capability is already built in to the american prius)

 

What is Sigma Automotive. Sorry for the questions, but I am new at this. Made a big change recently so bare with me.

 

Bottom line: Don't use it to force sustained propulsion. That's how fuel economy suffers with it, by substantial depletion of the battery which then requires ICE power to recharge. Its greatest value to me is to force ICE shutdown during coasting, gliding, or braking before the ICE is fully warmed. I use it for propulsion only on short, low-demand segments where it might be less efficient for the ICE to light, such as through a parking lot.

See this for a (rather long-winded) discussion.

 

Sigma Automotive – Accessories that make your car go cleaner, meaner & greener

Google is a wonderful tool.

 

The main trick is to not use the EV button in an attempt to save gas.

 

If you're running the battery down to two bars by using EV, that's exactly how you shouldn't use it. Again, limit its use for propulsion to low-speed, low-demand situations -- generally not what you have in traffic. I use it between red lights only if they are closely spaced, if I have no one following who might get too impatient for single-digit speeds (i.e., virtually anyone), and then only if I have a good charge on the battery already. In the process I generally use no more than 1-2% of the charge.

 

In hill country, I think it is worth thinking carefully about how the charge you are using in EV is going to be replaced. Thinking ahead, if it is likely to be by ICE-powered generation, then you lose. Period.

If, however, the very next thing you will do is to descend a long hill, steep enough to mean that unavoidable regeneration will do most of the replacement, then from a fuel economy point of view you may win.

That leaves the question of doing battery lifetime reduction harm by adding to the battery cycling. I think my residence and driving pattern make me one of very few people who might actually improve battery life by good use of EV mode. As I leave home, I go downhill a couple of hundred feet in the first mile on a residential road with a 15 mph speed limit (I'm a slow outlier going about 20 on it). Then I reach a 55mph limit road down a hill steep enough to accelerate in neutral at lower speeds, and able to maintain 55mph.

So, driving normally without an EV mode, the ICE comes on promptly, and runs during the whole low-speed stretch, warming itself up and charging the battery by two or three bars. Then, going down the long fast hill, regen to hold the speed down to 55mph pretty often puts me up to the full 8 bars by the time I turn off.

I think with an EV mod, I could profitably avoid starting the ICE at all in the slow mile, start down the long hill at a lower state of charge, and thus hit a peak at the bottom somewhat lower than 8 bars. I'd almost certainly save (a little bit) gasoline, and possibly also do the battery a little less cycling harm.

But that is an unusual profile. I suspect the farther you are from that profile, the less likely you are saving gasoline or failing to reduced the battery life.

 

Great for us and the factory we can learn & share from these mods. On very short trips it could be fine and give us a little more oomph in traffic, but it would seem we still want to let our ICE kick in for warmup before beginning high speed driving.

 

I'm pretty interested in this one. I live about 1.5 miles from town on a level little circle. It's literally all downhill to town, and town's flat. I always have a full charge by the time I get there, but it aggrevates me that the ICE bothers to warm up when I'm just stopping in town anyway, and that I can't go one block in a 20MPH zone without firing the ICE until it's fully warm.

This would/should allow me to get to town without firing the ICE at all. Does it automatically go back to "regular" mode when you go over 42, or do you have to turn it off? Is there an indicator light?

Sigma is the one on the CC stalk, correct?

Now, is there any disadvantage to using this from the start when it's cold? i.e. does the ICE warming help protect the electric motors in any way, or doesn't that matter?

 

Yours might seem to be a situation favorable for an EV switch, assuming you have nothing but no- or low-demand conditions on the downhill drive.

34 MPH is the threshold for EV, and yes it will cut off automatically when you reach that speed.

Sigma has the OEM switch. Coastal's uses the CC stalk. (I don't recommend that one.)

I've never seen any adverse mechanical effects described for using the EV switch in a cold car, other than a theoretical concern about the battery. But among the many safeguards the car has for the battery, the switch won't activate when the battery is very cold (generally, for me, when ambient temps have been in the teens or below). If there was a genuine risk to the battery, then you wouldn't think the overseas Prius would have the switch. Supposedly the North American model is not equipped with it because of emissions. But in your situation, obviously your emissions are better if the ICE never lights.

I caution folks to be aware of the potential warranty issue before installing the switch. Follow the link in my previous post for more.

 

How about this situation - I have a 2 mile commute. On the way to work I start down hill - I don't need hardly any acceleration on a 1/2 mile rolling flat and then I have a 100 yard slight up hill at the end of my commute. On the way home I start a short downhill and then level/rolling for 1/2 mile, and then up hill for 1/2 mile or so. Will the EV switch save fuel? Is there a way to charge the existing batteries other than by use of the ICE? Can I plug in and charge my battery somehow? If I could it seems like for my regular commute that would be the way to go.

 

About any fuel savings, hard to say. It might, as long as you limit its use to forcing ICE shutdown when it's not needed for propulsion during warmup.

What will save you a substantial amount of fuel, if you have somewhere to plug it in, is an engine block heater. I would highly recommend that over the EV switch, especially with your commute and climate. The EV switch's value to me would be considerably less if I could plug in the EBH at home and work. The car's worst fuel economy is in the first 5-10 minutes as the car warms, especially in the winter.

Either directly or indirectly, the battery is charged only by the ICE. Regenerative charging occurs when coasting or braking, but the car had to be brought up to speed by the ICE first, so that still is indirect ICE power.

There is no way to plug the stock Prius in to charge it. There are aftermarket plug-modifications available, but they all include extra batteries that are designed for sustained propulsion. They're rather pricey.

 

Thanks for that reply. I installed an EBH a few weeks ago. Works well. What you are saying make a lot of sense. I dont' think I am going to bother with a switch.

I must say this forum has helped me a lot. I've owned this car for several months and I am gradually getting better and better at eeking out MPG. My approach is mostly related to the big things - I drive a lot slower than I used to, I have my tires pumped way up, I block my grill, I installed a EBH, I try to pulse and glide where possible but in Vermont its often next to impossible to gain much with the P and G.

Last night I had a drive of about one hour round trip on secondary roads and my average was just shy of 70MPG! Not bad. I drove right at or slightly below the speed limit. I got stuck behind a semi and drafted a bit at slow speed. I find that if you stay around the 35 to 45 range you do real good. On the hwy I try to stick to 55 MPH and even though it is hilly here I do pretty good.

I'm very happy with this Prius except for one thing - it shuts down if you are in a situation where you need to start up a steep loose gravel drive or snowy drive from a dead stop and there is almost nothing you can do to change that. You have to be careful not to get into spots that you are not going to be able to get out of. For example, I have a friend that has a drive that goes down a steep hill to his door yard. Its fine getting down there. But getting out is impossible because you have to start from a dead stop and go up a moderately steep long hill. You do learn to apply very gentle gas to avoid spinning the tires, but in some situations you just cannot get up a hill that you could in almost any other vehicle with good tires and some winter driving experience. Also, if you are in a situation that you have to merge into traffic from a stop the same issue exists in certain situations. These things can be downright dangerous at times and Toyota should definately be warning people about this problem. But still, its worth it. I'm going to spend the money to get some very high end full bore snow tires for this car. Sorry about going off topic here - I just got typing along and - you know.

It would be nice to manufacture the Prius so that you could plug it in to charge and do some running around town on pure electric. That would be a wonderful improvement.

 

Don't pay for an EV switch all it takes is one piece of wire and two pins(taken out of the headlight assembly)..It costs nothing and is simple to install just make sure you get the pins all the way pushed into the connectors..That way you can have it and try it in different situations and it did not cost you a dime. The only downside with using your headlight lever is that at night you will flash your lights when engaging the EV mode. I also have the x-gauge on my scangauge shows me when EV is on/off..I need to make a video showing people how to do this method wish I would have thought of it before I did mine..One other thing there is no delay with this method like with some of the ones you buy..

 

One issue for my on my very short commute is that I do need to have some cabin heat and defrost available in winter right off the bat. If I use the EBH and prevent the ICE from coming on to warm up at the beginning of my commute which is downhill will I have cabin heat and defrost?

I'm thinking that I really will not get much benefit from this EV switch thing and I'm generally not one to futz around with lots of little details to get a tiny improvement. I don't have the mental energy anymore.

 

With only a few exceptions......
The best use of an EV switch is NOT at the beginning of a trip with a cold ICE. If you plan on traveling any distance, start up like normal and let the ICE warm up, it's going to need to anyway. Use the EV switch during your trip and at the end.
Who's to say what the SOC of the battery is going to be at first start-up.
If it's moderate to low, there is very little you will get out of EV mode, and the ICE is gonna start on it's own anyway.
If you were trying to get peak efficientcy out of the system, the idea would be to deplete the battery at the end of a trip, not the beginning.

Delepleting the battery at the beginning of a drive will have a huge impact on efficientcy for many miles to come in that drive, by depriving you of glide and stealth opportunities until the battery can recharge.

Using the EV switch, without significantly depleting the battery is ideal.
Use it to link glides and warp-stealth with moments of stealth(EV) that would not have been otherwise possible without causing the ICE to start.
That's the best use of an EV switch.
Of course, short driveway/parking-lot repositioning is probably it's original intent.

 

For those with a 1-2 mile commute... why not ride a bike?