Stoaty's Guide to Energy Efficient Driving of the Leaf

[TomT]

Yep, when range is not an issue and traffic permits, I like to fly along too. Lately I've been working late and running around 75 on the way home on relatively empty freeways...

I was cruising down the freeway at almost 80mph today, not getting 5.7 miles/kWh, and a LEAF pulled up along side and waved hi.

 

[Cheezmo]

I drove to DFW Airport and back from Plano last night, mostly open 70mph freeways. Here is the trip there (return isn't on carwings yet).

5.6kWh 6.2kWh 0.6kWh 22.8miles 4.1miles/kWh

I though that was pretty good. Didn't do anything exceptional on the highway other than use cruise control and make sure to keep a distance where I could react smoothly to any slow ups ahead. I think the return was about 3.7 or so, was chatting with relatives and driving more "normal".

This was kind of a test run for a 38 mile one way (76 mile round trip) to Ft. Worth in a couple of weeks. I realize I'm not going to make that without a charge somewhere unless I slow way down (which isn't going to happen).

I will say that thanks to the tips here, my daily driving has bumped up from 4.2 to just over 5. Not sure how long I'll keep playing the efficiency game, but I think it is worth knowing how to do it just in case.

 

[dgpcolorado]

Yes, once you know how to drive it you can easily beat 5 miles per kWh (on the dash) if you aren't in a hurry. At 8400 miles I still have a lifetime average of 5.7 miles per kWh--and my daily commute involves over 1,000 feet of elevation gain (and loss, of course).

Not in cool temperatures on steep curvy mountain roads where coasting is unsafe.

 

[elmobob]

My goal is to be at the absolute bottom of the list in Carwings, drive as hard and as fast as I can, use maximum A/C, and always arrive home with as low a battery as possible! :lol:

Any other eco-obsessive drivers out there?

ditto :lol:

 

[JPWhite]

I actually wish there was a mode where regen is turned off.

It's called Neutral

 

[JPWhite]

I agree, the car is for DRIVING, not tree hugging.

When I first started driving the car, I did the same. But since my typical day stretches the range limit of the car, it's easier to conserve than wait around in the middle of the day for a charge.

Yeah it took about 6 months for me to get over the novelty of instant torque.

Call me reformed I suppose.

Date	Grade	Rank	Energy Economy
Aug-11	Silver	2604	4.9 miles/kWh
Sep-11	Gold	2307	5.0 miles/kWh
Oct-11	Gold	2560	4.7 miles/kWh
Nov-11	Gold	1244	4.9 miles/kWh
Dec-11	Gold	2129	4.3 miles/kWh
Jan-12	Gold	2707	4.2 miles/kWh
Feb-12	Gold	1755	4.7 miles/kWh
Mar-12	Platinum	349	5.9 miles/kWh
Apr-12	Platinum	507	5.9 miles/kWh
May-12	Platinum	497	6.1 miles/kWh
Jun-12	Platinum	521	6.1 miles/kWh
Jul-12	Platinum	634	6.0 miles/kWh
Aug-12	Platinum	576	6.1 miles/kWh
Sep-12	Platinum	1314	5.6 miles/kWh
Oct-12	Platinum	493	6.1 miles/kWh

My CarWing numbers are off. 4.7 is about the best I can achieve on the dash, but the relative change is apparent.

 

[TimLee]

Thanks Stoaty for this excellent set of guidelines and your phenomenal effort on the battery degradation model.
Unfortunately I missed this topic back in September, was very busy then.
Glad your thread was quoted in a response to a new comer question.
I was initially a bit confused by your use of the word "coast" in the thread.
But after reading through the whole thread, is clear that the word "coast" kind of has two alternatives.
"Coast" with LEAF in neutral as long as there isn't any braking needed to control speed, or "Coast" with LEAF in Eco but minimizing the use of the accelerator to hold the energy use extremely low or allowing Regenerative braking if that is needed to hold speed to what you've set in Cruise Control.

 

[dgpcolorado]

Thanks Stoaty for this excellent set of guidelines and your phenomenal effort on the battery degradation model.
Unfortunately I missed this topic back in September, was very busy then.
Glad your thread was quoted in a response to a new comer question.
I was initially a bit confused by your use of the word "coast" in the thread.
But after reading through the whole thread, is clear that the word "coast" kind of has two alternatives.
"Coast" with LEAF in neutral as long as there isn't any braking needed to control speed, or "Coast" with LEAF in Eco but minimizing the use of the accelerator to hold the energy use extremely low or allowing Regenerative braking if that is needed to hold speed to what you've set in Cruise Control.

One clarification: In "Eco" you can coast by holding the A pedal at zero power (as viewed on the energy screen); if done correctly there is no practical difference between that and shifting to neutral.

That is a big advantage of Eco: the A pedal is mapped by power levels, both positive and negative. If you find and hold the zero position on the pedal it will stay at zero until you move your foot. This is very different from "D", which is mapped completely differently. While it is a bit more difficult to hold zero power in Eco than by shifting to neutral, it is more practical for short stretches of coasting, especially when one wants to feather in regen gradually to slow.

 

[TimLee]

Thanks Stoaty for this excellent set of guidelines and your phenomenal effort on the battery degradation model.
Unfortunately I missed this topic back in September, was very busy then.
Glad your thread was quoted in a response to a new comer question.
I was initially a bit confused by your use of the word "coast" in the thread.
But after reading through the whole thread, is clear that the word "coast" kind of has two alternatives.
"Coast" with LEAF in neutral as long as there isn't any braking needed to control speed, or "Coast" with LEAF in Eco but minimizing the use of the accelerator to hold the energy use extremely low or allowing Regenerative braking if that is needed to hold speed to what you've set in Cruise Control.

One clarification: In "Eco" you can coast by holding the A pedal at zero power (as viewed on the energy screen); if done correctly there is no practical difference between that and shifting to neutral.

That is a big advantage of Eco: the A pedal is mapped by power levels, both positive and negative. If you find and hold the zero position on the pedal it will stay at zero until you move your foot. This is very different from "D", which is mapped completely differently. While it is a bit more difficult to hold zero power in Eco than by shifting to neutral, it is more practical for short stretches of coasting, especially when one wants to feather in regen gradually to slow.

Right.
I still think referring to this as "coasting" is a bit inaccurate / misleading and confusing to some.
It is a somewhat close approximation to "coasting", which actually only occurs when the vehicle is in neutral. Which disengages the electronics driving the motor, but leaves it spinning, as the mechnical transmission has no neutral.
It took me a while to recognize that Neutral operation of the LEAF is probably OK.
Most driving instructors of ICE vehicles advise strongly against operating in Neutral, as you lose the engine braking, and the mechanical shock when drive is re-engaged isn't very good for the transmission / engine.
But apparently it is OK for the LEAF electronics.

 

[dgpcolorado]

Right.
I still think referring to this as "coasting" is a bit inaccurate / misleading and confusing to some.
It is a somewhat close approximation to "coasting", which actually only occurs when the vehicle is in neutral. Which disengages the electronics driving the motor, but leaves it spinning, as the mechnical transmission has no neutral.
It took me a while to recognize that Neutral operation of the LEAF is probably OK.

Well, "neutral" is no magnetic fields being applied, which is the same whether in Eco at zero power or by shifting to "neutral" with the shift knob. In an ICE car neutral is when the transmission is disengaged; there is no real equivalent in the LEAF.

Most driving instructors of ICE vehicles advise stronly against operating in Neutral, as you lose the engine braking, and the mechanical shock when drive is re-engaged isn't very good for the transmission / engine.
But apparently it is OK for the LEAF electronics.

Exactly right. Turning the magnetic fields in the motor off or on is very different from disengaging or engaging a mechanical transmission. Nevertheless, the safety issue of not having any "engine braking" (regen braking in an EV) is something to be considered. By shifting to neutral there is no slowing when one's foot is removed from the accelerator and that delays slowing somewhat until the brake pedal can be applied. If you aren't expecting that it could cause problems. But I presume that nobody will coast by shifting to neutral while in heavy traffic and following too closely. At least I hope that is the case! In such conditions it is much safer to hold a neutral postion with the A pedal in Eco.

One exception to the general rule about not driving in neutral in an ICE car: in icy conditions it is safer to get through a slick patch in neutral. In a manual transmission car one learns to just step on the clutch as soon as such conditions are encountered; it is tougher to do with an automatic transmission car. The reason for this is that when at the limits of tire adhesion any slight acceleration/deceleration can break the tires free and cause a skid. (With modern traction or skid control systems it may no longer be the case, I wouldn't know.)

 

[DaveinOlyWA]

Thanks Stoaty for this excellent set of guidelines and your phenomenal effort on the battery degradation model.
Unfortunately I missed this topic back in September, was very busy then.
Glad your thread was quoted in a response to a new comer question.
I was initially a bit confused by your use of the word "coast" in the thread.
But after reading through the whole thread, is clear that the word "coast" kind of has two alternatives.
"Coast" with LEAF in neutral as long as there isn't any braking needed to control speed, or "Coast" with LEAF in Eco but minimizing the use of the accelerator to hold the energy use extremely low or allowing Regenerative braking if that is needed to hold speed to what you've set in Cruise Control.

Tim the term should not be interchangeable. In Prius-speak, using no power while in gear is referred to as "deadbanding" or the desire to hit the zone where there is no measurable power being transferred to the wheels or to the battery.

in reality, this is VERY difficult and the meter only shows no power transfer due to its shortcomings. Use a meter that reads CAN BUS and you will see a constant fluctuation with changes in polarity. This can realistically never be as efficient as neutral. But then again, with practice the differences can be negligible.

i for one, choose not to devote that much attention to the meter especially when a quick shift to reverse gets me to neutral.

because there is no touching of anything in the motor, shifting gears really causes no extra strain. The shifter knob is a different story but no knowledge of how long those switches are expected to last.

 

[iluvmacs]

Tim the term should not be interchangeable. In Prius-speak, using no power while in gear is referred to as "deadbanding" or the desire to hit the zone where there is no measurable power being transferred to the wheels or to the battery.

in reality, this is VERY difficult and the meter only shows no power transfer due to its shortcomings. Use a meter that reads CAN BUS and you will see a constant fluctuation with changes in polarity. This can realistically never be as efficient as neutral. But then again, with practice the differences can be negligible.

"Deadbanding" in a Prius is acceleration using power directly from the engine to the wheels. No (or very minimal) power in or out of the battery via the electric motor(s). This is viewed as the most efficient way to accelerate in a Prius, and a technique I've used for many of my years hypermiling. See http://priuschat.com/threads/whats-deadband-acceleration.19156/" onclick="window.open(this.href);return false;

Getting no arrows flowing at all in a Prius is known as "gliding", generally by feather-footing the accelerator pedal. You are correct that during a glide as shown on the Prius MFD, there is often still a small mount of draw from the battery. I can see this quite easily on the CAN-View in my Prius, but hitting zero amps of flow is almost impossible to hit and maintain. Going by the "no arrows glide" on the MFD is the easiest and most reliable/repeatable method. The other option is to shift to Neutral instead of feather-footing a glide, which gets you closer to zero power draw, but still not exactly there. This takes a lot of effort and can be dangerous in many driving situations. I've always defined "coasting" to be when no pedals are being depressed at all, and it is in gear (so regenerating slightly).

 

[DaveinOlyWA]

one is the result of the other. you deadband in order to glide. doing this slowly bleeds off speed until you reach your lower limit, then you "pulse" or accelerate slowly back up to your upper limit. then you deadband to resume the "glide"

 

[iluvmacs]

one is the result of the other. you deadband in order to glide. doing this slowly bleeds off speed until you reach your lower limit, then you "pulse" or accelerate slowly back up to your upper limit. then you deadband to resume the "glide"

You still have it wrong. The deadband is the particular technique used during the slowly accelerating pulse (arrows straight from engine to wheels), then you glide (no arrows).

 

[DaveinOlyWA]

You still have it wrong.

Oh crap. No wonder i never got 75 mpg!

 

[LEAFfan]

Thanks Stoaty for this excellent set of guidelines and your phenomenal effort on the battery degradation model.
Unfortunately I missed this topic back in September, was very busy then.
Glad your thread was quoted in a response to a new comer question.
I was initially a bit confused by your use of the word "coast" in the thread.
But after reading through the whole thread, is clear that the word "coast" kind of has two alternatives.
"Coast" with LEAF in neutral as long as there isn't any braking needed to control speed, or "Coast" with LEAF in Eco but minimizing the use of the accelerator to hold the energy use extremely low or allowing Regenerative braking if that is needed to hold speed to what you've set in Cruise Control.

Tim the term should not be interchangeable. In Prius-speak, using no power while in gear is referred to as "deadbanding" or the desire to hit the zone where there is no measurable power being transferred to the wheels or to the battery.

in reality, this is VERY difficult and the meter only shows no power transfer due to its shortcomings. Use a meter that reads CAN BUS and you will see a constant fluctuation with changes in polarity. This can realistically never be as efficient as neutral. But then again, with practice the differences can be negligible.

+1! I challenge anyone to get higher m/kW h using 'feathering' instead of 'N'.

i for one, choose not to devote that much attention to the meter especially when a quick shift to reverse gets me to neutral.

because there is no touching of anything in the motor, shifting gears really causes no extra strain. The shifter knob is a different story but no knowledge of how long those switches are expected to last.

 

[mrdcmills]

I feel sorry for the people stuck behind you. Aren't you just reinforcing the myth the electric cars are little shirtboxes that can"t get out of their own way? I roll with the traffic and still maintain 4.2-4.4 avg. every month. Pissing other motorists off is not going to further our cause. I ride a motorcycle with the stock pipe. As a biker I pay for the yahoos with the straight pipes. Think about it

 

[DaveinOlyWA]

Why is breaking the law so coveted that ones who obey the law are so persecuted?

 

[DaveEV]

The shifter knob is a different story but no knowledge of how long those switches are expected to last.

Phil has stated that the shifter has nothing really to wear out, it uses hall-effect sensors, not switches so should be very, very reliable.

 

[DaveinOlyWA]

Neutral it is!

The shifter knob is a different story but no knowledge of how long those switches are expected to last.

Phil has stated that the shifter has nothing really to wear out, it uses hall-effect sensors, not switches so should be very, very reliable.