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Discussion Starter · #1 ·
Just picked up my Bolt earlier this week.

Anyone have any range modifications they found worth doing? For example, many other EVs have some sort of aero wheel covers (e.g. eGolf / Ioniq EV). The Bolt's wheels are rather open, suggesting they might not be so aerodynamic. Anyone try putting some saran wrap or anything over them just to experiment?

I did pump up the tires to their max pressure, around 44 PSI.

How about taping down the hood crack, or finding things to remove to reduce weight?
 

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Hypermiling will come down to driving slower and avoiding regen/brakes as much as possible. This is simply the #1 way to drastically extend range.

All other things you mention are minor. You could fold in the mirrors for a small boost too. If you want major improvement in range from a modification, you will need a major modification such as boat-tailing the rear of the car (making it teardrop shaped). Some people have made these aerodynamic extensions and mounted it to the car using a receiver/hitch.
 

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I think a modification that makes more sense is changing out the rims. The Bolts rims are pretty heavy. I think someone here has posted that they switched to the Chevy Cruze eco rims and they made a big difference.
 

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Hypermiling will come down to driving slower and avoiding regen/brakes as much as possible. This is simply the #1 way to drastically extend range.
Hi ... Can you help me a bit with this statement ? It seem backwards, Wouldn't I want to use regen ?
Are you saying that for best mileage would be to keep in "D" ?

I currently use "L" in traffic / around town and do try to put myself in "D" when on the freeway while keeping an eye way out front so that I can coast as much as possible. And I clearly see slower is better.

Is this current method of my settings what I should be doing?
 

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Discussion Starter · #5 ·
Hi ... Can you help me a bit with this statement ? It seem backwards, Wouldn't I want to use regen ?
Are you saying that for best mileage would be to keep in "D" ?

I currently use "L" in traffic / around town and do try to put myself in "D" when on the freeway while keeping an eye way out front so that I can coast as much as possible. And I clearly see slower is better.

Is this current method of my settings what I should be doing?
Oh god please no don't start this discussion again >:) -- there are a million threads on it. The short story: it is most efficient to never slow down (e.g. coast) because regen will never recover 100% of the energy during deceleration. Of course you need to slow down, though, so using regen to slow down is far better than disc brakes (which is why I drive in L & use the paddle, to prevent disc brake use). The catch is, you have to hold the pedal in a position to go the exact speed you want and never regen more than needed.

With that out of the way 0:)-- lighter & more aero wheels sounds enticing, but that can't be cheap.
 

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Using L in traffic just allows you to stop your car better without using the actual brakes. I use it in traffic because of the safety of it, but the thing about getting the best mileage is not to touch your brakes at all. Actually to get the best mileage the trick is to not use regen at all...

An object in motion stays in motion unless acted upon by an external force. Something important to consider here is the less acceleration, or deceleration) you do, the better mileage you get. Well, only at lower speeds when we don't have to factor in the exponential resistance of air flow. Regeneration is great, but take in consideration that not all the energy from stopping is put back into the battery. If you could travel to point A to B at 40 mph you would get better mileage than stop and go traffic.

Using L in traffic is the best for avoiding touching your brakes and is an amazing safety feature to avoiding collisions! I use D on highways because the regen is less, but I wish there was another mode that had no regen at all for highway driving.
 

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Lightweight wheels make a bigger difference than what people think. The rotational inertia of turning the wheels can be quite substantial since this is the only thing the electric motor is trying to move. The other thing that people don't realize is a huge factor in air resistance is the side mirrors. In the future you will see cars with no side mirrors, but cameras in their place.
 

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:eek:Since someone else brought it up, I'll add my opinion. As a Prius owner, and previously a BMW i3, I tend to drive conservatively. While never into hypermiling, I do practice some techniques. With the i3, one pedal driving was 100% all the time and not selectable. I personally like one pedal driving. I've had my Bolt for one month and have driven in "L" most of the time. My daily commute is 9.6 miles with 8 miles interstate. When I exit, I shift from "L" to "D", apply a little throttle to maximize coasting as much as possible. After reading several threads here on the subject, I'm thinking "D" would be best to maximize range. This morning I had to go out, started with 222 miles projected range and returned with 214, eight miles. All city driving, 35-50 mph. I left my Bolt in "D" and coasted when appropriate, using the steering wheel paddle to slow and stop as much as possible. I actually drove a total of 22 miles, with very little regen. Unless this was a fluke, it appears under these circumstances, "D" is most efficient, but not without a little effort. For the record, my first full charge resulted in 260 miles with 33 remaining. The second was 240 miles with 26 remaining. I'm on my third charge and I should break 300. Thoughts?
 

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:eek:Since someone else brought it up, I'll add my opinion. As a Prius owner, and previously a BMW i3, I tend to drive conservatively. While never into hypermiling, I do practice some techniques. With the i3, one pedal driving was 100% all the time and not selectable. I personally like one pedal driving. I've had my Bolt for one month and have driven in "L" most of the time. My daily commute is 9.6 miles with 8 miles interstate. When I exit, I shift from "L" to "D", apply a little throttle to maximize coasting as much as possible. After reading several threads here on the subject, I'm thinking "D" would be best to maximize range. This morning I had to go out, started with 222 miles projected range and returned with 214, eight miles. All city driving, 35-50 mph. I left my Bolt in "D" and coasted when appropriate, using the steering wheel paddle to slow and stop as much as possible. I actually drove a total of 22 miles, with very little regen. Unless this was a fluke, it appears under these circumstances, "D" is most efficient, but not without a little effort. For the record, my first full charge resulted in 260 miles with 33 remaining. The second was 240 miles with 26 remaining. I'm on my third charge and I should break 300. Thoughts?
wow those are some good numbers... It's getting confusing all these modes :(
 

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The modes are confusing, but the concept of what is most efficient is not.

Coasting > regen > friction brakes.

In other words, pay attention to what traffic is doing and anticipate it so that you minimize regen and braking. Usually this means leaving a larger gap between your car, and the one ahead.
 

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The modes are confusing, but the concept of what is most efficient is not.

Coasting > regen > friction brakes.

In other words, pay attention to what traffic is doing and anticipate it so that you minimize regen and braking. Usually this means leaving a larger gap between your car, and the one ahead.

Good advice, and succinctly stated. Phrasing the same concept differently, regen never puts back in the battery what energy it took to put the EV into a state where regen (or braking) was necessary. To the extent possible, anticipate driving to minimize regen.

Thanks!
 

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The other thing to note besides D > L > braking (coasting > regen braking > disc brakes) is that energy use goes up quite a bit at higher speeds. This has been discussed before but am tersely repeating this for the benefit of anyone new to the forum.

It is NOT a linear relationship which is what most people immediately think - by this I mean going 66 mph does not 10% more power than 60 mph (60 + 6 mph), it takes more. Going 80 mph is in my experience about twice as consumptive of energy as 60 mph. (This comment is not meant to be exact, it is an order of magnitude comment, am posting from outside the US on vacation).

so if you are trying to stretch your distance /hypermile, get comfortable with a lower speed! I recently posted about a trip to Western MA from Boston around the 4th of July, and I drove ~ 85 mph to our friends to not be late... and got something like 3.2 miles per kW rather than my usual 4-4.5 per kW.
 

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As a hybrid-trained person and an (occasional, non-compulsive) hypermiler I state:

1. Driving style and speed is by far the largest factor.

2. If you can select your route to avoid challenging terrain and/or poor road conditions, that may help.

3. The outside temperature is not under you control, so no discussion about these

4. At high speed, open windows and especially the roof rack - even empty - are a large factor, too

5. Tire pressure and gross weight are factors, too, but not quite proportionate with fuel consumption (= if you drop pressure by 10% from 40 psi to 36, your consumption will not increase by 10%)

6. The rest of improvements are of emotional value mostly.
 

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:eek:Since someone else brought it up, I'll add my opinion. As a Prius owner, and previously a BMW i3, I tend to drive conservatively. While never into hypermiling, I do practice some techniques. With the i3, one pedal driving was 100% all the time and not selectable. I personally like one pedal driving. I've had my Bolt for one month and have driven in "L" most of the time. My daily commute is 9.6 miles with 8 miles interstate. When I exit, I shift from "L" to "D", apply a little throttle to maximize coasting as much as possible. After reading several threads here on the subject, I'm thinking "D" would be best to maximize range. This morning I had to go out, started with 222 miles projected range and returned with 214, eight miles. All city driving, 35-50 mph. I left my Bolt in "D" and coasted when appropriate, using the steering wheel paddle to slow and stop as much as possible. I actually drove a total of 22 miles, with very little regen. Unless this was a fluke, it appears under these circumstances, "D" is most efficient, but not without a little effort. For the record, my first full charge resulted in 260 miles with 33 remaining. The second was 240 miles with 26 remaining. I'm on my third charge and I should break 300. Thoughts?
Which generation? Gen II (2004-2009), Gen III (2010-2015), Gen IV (2016+)?
I've been driving Gen II since 2004. There is a "Prius glide" technique whereby you have your foot JUST BARELY pushing on the accelerator. The car "slips" into what feels like neutral but it isn't in neutral and you MUST have your foot on the pedal. No fuel providing motive power, no regen braking to slow down. There are places where the slope is such that I can keep speed limit using no power. Without using "the glide" fuel is necessary to avoid slowing down due to foot off the accelerator regen. I find it nearly impossible to do this in my in-laws' 2010. It is a VERY GOOD but likely unplanned "design feature" of the Gen II.

The modes are confusing, but the concept of what is most efficient is not.

Coasting > regen > friction brakes.

In other words, pay attention to what traffic is doing and anticipate it so that you minimize regen and braking. Usually this means leaving a larger gap between your car, and the one ahead.
Is your definition of coasting "foot off the accelerator" or is the "Prius glide" possible prior to hitting regen? That would be ideal (fantastic really). The whole idea of "one pedal driving" being "good for mileage" is the antithesis of "good for mileage". You use more power going more distance getting to the red light so the stronger regen can stop the car in a shorter distance.

I ASSUME (perhaps incorrectly) that the Bolt will regen when the brake pedal is applied unless "panic mode" pressure is used or at very slow speeds - ala the Prius which doesn't touch the friction brakes under normal brake pressure until the speed is below about 8 MPH.
 

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Is your definition of coasting "foot off the accelerator" or is the "Prius glide" possible prior to hitting regen? That would be ideal (fantastic really). The whole idea of "one pedal driving" being "good for mileage" is the antithesis of "good for mileage". You use more power going more distance getting to the red light so the stronger regen can stop the car in a shorter distance.

I ASSUME (perhaps incorrectly) that the Bolt will regen when the brake pedal is applied unless "panic mode" pressure is used or at very slow speeds - ala the Prius which doesn't touch the friction brakes under normal brake pressure until the speed is below about 8 MPH.
The Prius has slight regen with foot off the accelerator. I mostly coast by using N, and sometimes coast by applying slight pressure on the accelerator.

Regen is about 1/3 efficient at recapturing kinetic energy. For that reason, coasting to lose speed is more efficient. Since it isn't practical to coast all the way to a complete stop, regen is the next best thing.

I haven't got a clear answer on how the Bolt behaves with regard to using the brake pedal for regen. People refer to it as blended brake/regen, which makes it ambiguous as to if it uses both friction and regen at the same time, or if it only switches to friction after maximum regen has been reached. As you correctly point out, the Prius uses only regen with the brake pedal until exceeding the ability to regen, at which point the friction brakes transition in.
 

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Regen braking to recapture kinetic energy is far more than 33% efficient.

I'd put it at closer to 80-90%

I get pretty much the same mi/kWh on a long ascent/descent R/T as I do driving on the flats. It's just the efficiency of the electric motor, some loss in the charging circuitry and the efficiency of the battery. All those components are very efficient.
 

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Regen braking to recapture kinetic energy is far more than 33% efficient.

I'd put it at closer to 80-90%

I get pretty much the same mi/kWh on a long ascent/descent R/T as I do driving on the flats. It's just the efficiency of the electric motor, some loss in the charging circuitry and the efficiency of the battery. All those components are very efficient.
A previous thread on the topic estimates it more like 65%:

http://www.chevybolt.org/forum/10-technical-discussion/9354-how-efficient-bolt-regen.html
 

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Regen braking to recapture kinetic energy is far more than 33% efficient.

I'd put it at closer to 80-90%

I get pretty much the same mi/kWh on a long ascent/descent R/T as I do driving on the flats. It's just the efficiency of the electric motor, some loss in the charging circuitry and the efficiency of the battery. All those components are very efficient.
I am highly skeptical that you recover 80% of energy used to accelerate, there are too many factors fighting against that. During acceleration the engine has to use enough energy to move the mass of the car, overcome wind resistance, overcome rolling resistance, losses due to heat, mechanical energy loss and any losses in transmission across the wires. Conversely during regen braking it can only recover the energy from slowing the mass of the vehicle. Wind resistance and rolling resistance are still pushing against the car, there are still losses to heat, mechanical losses and transmission from engine to battery. So you still have all of that reducing the amount of energy that could be captured by regen braking in comparison in to how much was used to get the car up to that speed it was at. Physics is not our friend when it comes time to recapture energy, there are always losses of energy when you transform it from one form of energy into another. It gets compounded when there are factors limiting the amount of energy you have available to recapture.

I of course haven't taken the time to collect the needed data to actually do the math on all of this to show empirically what the efficiency on the regen brakes is but just going from basic laws of physics I don't see how it can be 80% or higher. I would be quite impressed if they were able to get over 70%, that would phenomenal efficiency.

Also that is without even mentioning ratio of time that the engine is pushing the car forward (accelerating or maintain speed) compared to time the regen brakes are being used. I would expect that ratio to be at least in the 3 to 1 range, if not higher.
 

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I thought this was worth cross posting to this discussion.

surgeonFWW,

"The approach I have used is to learn to use the regen paddle as a "hand brake" in all instances. If I am in L, it doesn't do much, but if I am in D, I am slowing for that half second while I realize I may need the foot brake. The motor memory is the same for both driving modes. I also use the paddle to stop cruise control rather than tapping on the foot brake."

That is what I do. I have gotten confused by this in the past, and I think always using the paddle is a good idea. Just a heads up: The paddle does nothing when you are in neutral, as the motor is out of the loop. First time I tried it I got a very sick feeling in the pit of my stomach. :)
 
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