EV Specific Driving Tips?

[vskid3]

What do EV owners do to maximize range? Of course there's the obvious like being sparing with the climate control and preheating or cooling, but there are some techniques I've read about that almost seem contradictory to gas techniques.

Most people say they use "L" gear or maximum regen when releasing the gas (throttle, power, go?) pedal and get better range. Are they just bad drivers and the regen is a bandaid? I've read about members here doing it as well. What about pulse and glide vs constant speed? Fast or slow acceleration?

So what are your EV driving tips that might be different than a dino-juice powered car?

[JSH]

It may depend on the car but I don't see why using L for regen would help. When you press on the brake in an EV you get regen unless you are really braking hard and then the friction brakes kick in.

Hard acceleration doesn't seem to hurt mileage as much as with a gas car.

[cowmeat]

Most people say they use "L" gear or maximum regen when releasing the gas (throttle, power, go?) pedal and get better range. Are they just bad drivers and the regen is a bandaid? I've read about members here doing it as well.

It may depend on the car but I don't see why using L for regen would help.

Why would you NOT want to drive in "L"? I use every trick I can to achieve better gas mileage, and this one comes courtesy of the manufacturer! It takes a bit to get used to if you haven't driven a car that has this feature, but after driving two Insights which I manually added brake regen buttons to there was no learning curve for me.

I always drive my Volt in "L", it functions basically the same way my brake regen button did in my Insights, but it's factory equipment that I didn't have to install myself and I don't have to press a button to make it work. Power is added back to the big battery as I slow, instead of being lost to friction.

I can feather the gas pedal and regen power back into the battery almost indefinitely on any slight downslope without losing a lot of momentum. There's a long, barely noticeable grade on my way to work that ends at a stop sign, and I've actually watched my car recharge a tenth of a kWh as I slow to a stop there.

That's free miles I'm adding back in that battery, people!

[sendler]

There was a big arguement on the Bolt thread where the non EV drivers were actually going so far as to say that the engineers were stupid for designing it with the "one pedal" driving option. They felt it was a very inefficient driving method since there was no true way to disengage the drive train and coast.

[Daox]

P&G is not a useful method in an EV and will probably result in lower range. Lower amp draw from the batteries will result in more usable capacity. The peukert effect basically says the faster you draw power from a battery the less usable capacity you get. Lithium is a lot better than other battery chemistries for this, but its still a thing. This also lends itself to slower acceleration and lower overall speed.

I would recommend avoiding regen when possible. The energy conversion losses (inertia to electrical to chemical and back) are still there, so its going to be more efficient to not brake/regen if possible.

Electric motors still do have an efficiency curve. It is a lot flatter than an internal combustion engine, but it does exist. Here is an example from a series wound DC electric motor.





I'd imagine AC motors have an even more flat line, but I am not sure on that. I googled for an image and found the small one below. So, this would lend itself to not accelerating too slowly haha.





All in all, all of these factors are MUCH smaller than they are on their ICE counterparts. Where some could achieve 50 to 100% over EPA numbers, getting even 25% above EPA in an EV is going to be much harder to do simply because the inefficiency in EVs is just so much smaller. There just isn't as much inefficiency to improve upon.

Great topic btw!

[cowmeat]

I would recommend avoiding regen when possible. The energy conversion losses (inertia to electrical to chemical and back) are still there, so its going to be more efficient to not brake/regen if possible.

Electric motors still do have an efficiency curve. It is a lot flatter than an internal combustion engine, but it does exist. Here is an example from a series wound DC electric motor.

I dunno man, I'm already beating the EPA EV numbers for the Volt by like 65% with no mods other than airing up the tires, and I think the regen plays a big part in that since I'm still a relative noob at driving an EV.

Do I try to avoid slowing down? Absolutely, just as any hypermiler does! But any time I do have to slow down for any reason, the car repays me by adding a little more range.

Not sure how straight-up EVs work, but I think driving in "L" and playing the regen is really helping me beat the EPA numbers.

Wish there were more Volt drivers here! I'm pretty much winging this as I go, so I'm sure there are more effective methods than I'm using

[NeilBlanchard]

Ecodriving an EV is the same as any car - coasting is best when you need to continue moving forward. Regen is only for when you need to slow down - and it is obviously better than friction brakes.

Drive like you don't have brakes - the exact same principle as you would for an ICE.

Put it in neutral and coast - the e-Golf has this as the default. In our Leaf, I pop it into the R position (when moving faster than 7MPH) and it instantly goes into neutral; or hold it in N for 2 seconds. Put it back into D for some regen (like a downshift), or bump it a second time to get into B for more regen.

Ironically, in the Leaf you have to put it into D/B in order for there to be regen on the <b>brake</b> pedal. But the e-Golf is the best here, as well.

Doax has it right - electric motors don't idle, and they peak at ~92% (or slightly higher!) efficiency, and they hit that at very low RPM's. Most EV's have a reduction gear, and a differential that also reduces the wheel RPM vs the motor. A Leaf, for example has the motor "redlining" just shy of 10,400RPM at ~94MPH, so it hits ~80-85% efficiency at <10MPH.

http://livingleaf.info/2010/11/nissa...-transmission/

The bottom line is there is not much "fat" to squeeze out of the drivetrain - so it comes down to using the accelerator pedal as little as possible.

[sendler]

The Volt uses permanent magnet motors. Teslas have induction motors. But the concepts of efficiency versus load and versus speed may be similar.

[vskid3]

Thanks everyone, that's about what I figured. Part of my confusion with driving in L is it seems like some describe it as if they're either using energy or regen with no coasting (I'm sure there are people who drive like that, I've seen them do it with the gas and brake). Just wanted to make sure coasting was still valid.

I've test driven a Leaf twice, but both times were just a mile or two drive up the road and back. Volt was a 10-15 mile drive with a few miles on the freeway. Smart EV was about 6 miles of city. I liked all of them and wouldn't hesitate to buy any (I'd have to do more research on the Smart's reliability), but none of those drives were long enough to really give a feel of how to maximize range (unless driving down a perpetual hill is a viable scenario). My biggest complaint between the 3 was the Leaf's power steering being so helpful I thought I was going to throw the steering wheel through the door. Funny thing is despite the Smart being the smallest, its battery didn't reduce the usable space inside the car. Also rode in a Model S 85 the Volt's dealer had, I can't imagine how it must feel accelerating even faster than that in the performance and AWD versions.

Something interesting about the gen2 Volt is the regen paddle that you can pull to get regen similar to L and lighting the brake light. I think I would drive in D if I had that to make coasting easier while still being able to get some good regen without risking the disc brakes activating. We'll just have to see what's on the used market when the Prius finally dies.

[JSH]

Originally Posted by cowmeat

Why would you NOT want to drive in "L"? I use every trick I can to achieve better gas mileage, and this one comes courtesy of the manufacturer! It takes a bit to get used to if you haven't driven a car that has this feature, but after driving two Insights which I manually added brake regen buttons to there was no learning curve for me.

L is not there as a fuel economy tool. It is LOW gear to give you the equivalent of more engine braking for descending steep slopes.

Driving in L makes regeneration more aggressive and allows you to drive with one pedal. You can do the exact same thing with the brake pedal as applying the brake pedal uses regeneration to slow the car (Unless you are in a true panic stop and then the friction brakes are also used)

I experiment driving in L today with my Spark EV. The instrument panel in my Spark shows KW used or gained through regen so the effects are easy to see. In L when I take my foot off the "gas" pedal the car regenerates at a rate of about 20 kw. That is the equivalent of moderately stepping on the brake pedal. In drive, lifting the gas pedal gets about 1 KW of regen and the car coasts almost effortlessly. If I press on the brake I get easily modulated regen from 1 to about 50 KW.