I got to see and sit in a Bolt today

[michael]

There are two Bolts on display at the Los Angeles auto show. I got to check it out pretty thoroughly and it looks really good

I had been concerned that it would be too small. It is smaller on the outside than my Focus was, but far more spacious inside. Great headroom in front and good in the rear. Plenty of rear legroom

Charging had some interesting options. One was the option to immediately charge to 40% and then to do a timed charge for the remainder. In essence this provides the option to use only the lower 40% of the battery charge window and provide 80 mile class range. This should be great for battery longevity

Another option was hill top reserve. The Chevy people were clueless about this but I bet this gives the option for hill top people to terminate charge early and regen on the way down rather than being forced to use friction brakes

The downers were things we already knew..,lack of homelink. Nobody could confirm resistive vs heat pump

Interior looked good to me. Leather seats were good looking

Rear storage area was much bigger than Focus but seemed smaller than Volt

All in all very nice. Confirms my plan to grab one

 

[elpwr]

If you're trying to optimize battery life you don't want to use the lowest 40% of the charge. You want to use the middle 40-60%. Battery life is optimized by minimizing use of the extreme upper and extreme lower state of charge.

My Spark EV has provisions for immediately charging to 40% and later doing a timed charge, also. It's called "priority charging". Probably intended to get the battery into its optimum storage range immediately. I do wish the Bolt had provisions, like my Tesla, for terminating the charge at an adjustable upper percentage. Again, battery life is extended by terminating the charge at 80 or 90% instead of charging full. In fact, Tesla recommends this -charge to 80% daily and only do a full charge when needed.

I accomplish the same thing with the Spark EV by setting the departure time about one hour later than I actually intended. Thereby, taking it off the charger an hour early and avoiding a full charge when not necessary. Probably can do the same thing with the Bolt.

 

[WetEV]

Living on top of a hill, I'd like a "hill top reserve". I've seen other discussions and agree that this is to allow for regen on the way down as suggested above.

 

[user 387]

Hill top reserve would also be a way of not topping off the battery, (topping off may lead to shorter life in the long run). This may be a good option for most people, whether they live on a hill top or not.

 

[Maxters]

Why would keeping the battery full shorten the battery life?

 

[michael]

Why would keeping the battery full shorten the battery life?

That's an inherent characteristic of lithium cells. Lithium is deposited on the electrodes and is no longer available for charge/discharge. This happens most at high levels of charge and at high temperatures. The longer the battery sits at a high level of charge, the more lithium is lost.

This is different that most other battery chemistries which are "happy" when charged.

Here is a talk by the guy who literally "wrote the book" on the subject

https://www.youtube.com/watch?v=pxP0Cu00sZs

 

[michael]

Hill top reserve would also be a way of not topping off the battery, (topping off may lead to shorter life in the long run). This may be a good option for most people, whether they live on a hill top or not.

I absolutely agree with you. It will be interesting to see how much the charge is reduced when this mode is used. If 10% it would be a very big deal in terms of battery life.

While I agree this is a worthwhile feature for its stated purpose (allowing regen on initial downhill) it may also be a cute way to circumvent the EPA's way of punishing range estimates when lower charge options are provided.

 

[michael]

If you're trying to optimize battery life you don't want to use the lowest 40% of the charge. You want to use the middle 40-60%. Battery life is optimized by minimizing use of the extreme upper and extreme lower state of charge.

That point is not clear. Army studies have shown that lithium batteries cycled between 50% and 0% have longer life than those cycled between 75% and 25% or between 100% and 50%. And of course all of these were better than between 100% and 0%

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA527711

 

[WetEV]

Army studies have shown that lithium batteries cycled between 50% and 0% have longer life than those cycled between 75% and 25% or between 100% and 50%. And of course all of these were better than between 100% and 0%

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA527711

Figure 1: Unless I'm misreading it, 50% to 100% was worse than 0% to 100% cycling.

 

[elpwr]

If you're trying to optimize battery life you don't want to use the lowest 40% of the charge. You want to use the middle 40-60%. Battery life is optimized by minimizing use of the extreme upper and extreme lower state of charge.

That point is not clear. Army studies have shown that lithium batteries cycled between 50% and 0% have longer life than those cycled between 75% and 25% or between 100% and 50%. And of course all of these were better than between 100% and 0%

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA527711

That's a 6 year old study on military 18650 batteries. Not very relevant to current thinking, nor current recommendations, on most chemistries used in automotive applications.

 

[michael]

Do you have a reference on that? Many people have suggested that mid-charge is better, but I haven't seen research to support that belief.

This is the only paper I have found that shows data on this subject...everything else I've so far seen expresses opinion without test results to support it.

This is important to me...previously I had only 80 miles range and a 50 mile drive, so by necessity I charged across the mid range. In the case of the Bolt I will have the flexibility, so I'm really looking for a supportable answer. I actually could run it between 40 and 15%, for example. Running it between 60 and 35% would require me to do the same dopey stuff I had to do to get the Focus to stop at 80%. I think we can all agree that running it between 100% and 75% would be the worst choice.

 

[elpwr]

You can find iendless studies, surveys, and technical papers on lithium batteries. Most are in general agreement but there are a few outliers. One source that is frequently quoted and well respected is the Battery University. Look at the chart from them in the link below. Check "how to prolong battery life" under the lithium ion column. "Operate in the mid SOC from 20% to 80%."

http://batteryuniversity.com/learn/article/do_and_dont_battery_table

My Tesla model S is almost 3 years old and has 30,000 miles. The battery has degraded 1.8% in rated range since new. A fairly large survey on the Tesla forum has shown an average of 3-5% degradation for most three-year-old model S Teslas.

I try to operate my Model S in the 20–80% battery range but on occasions, when needed, I'm not afraid to go beyond those limits. I just try not to make a general habit of it if not necessary. I don't think you need to be neurotic about babying the battery but following some general precautions, I think, can help minimize the inevitable battery degradation.

 

[michael]

Battery University is well regarded, but it doesn't answer this specific question. The Army paper is the only one I have yet found that does.

Battery U says to run the battery between 80 and 20%, but I'm sure you don't interpret this as a recommendation to charge to 80 and discharge to 20 repeatedly...it is well documented that shallow DOD gives better life. Battery U is simply saying try to keep it within this range.

As you say, I have found endless articles, etc. on lithium batteries, but I have found only one that did tests to answer this question. It seems a shame to dismiss this one paper as not applicable unless there's something that is more relevant.

As noted on my edit above, I really want to know the answer. I did 54,000 miles in a Focus that demonstrated battery fade when all the people on the Focus board said "Don't worry, it's got thermal management, the car will last forever".

 

[Eastocean]

In October at the Delaware Auto Show, I also got to sit in a Bolt, open all the doors and hatches. I agree that it feels roomier. Getting in the backseat, you need to watch your head on the top of the door. Leg room in the back seat felt slightly smaller than the Leaf . Nothing was a red flag, and I plan on buying a Bolt as soon as I can order one.

 

[ScooterCT]

Sat in a very pretty (I was shocked) red Bolt today at the CT Auto Show. I went to the show appreciating the specs, but expecting a real dog of a car. I was shocked to find myself responding really positively to the car. I had a chat with a very pleasant Chevy rep from Florida. She said she had the same response as me - she expected to dislike it, but loved it in person. She's buying one as soon as they're available in Florida.

The only red flag I noticed was bumping my head on the door frame getting into the back seat. Other minor negatives were a cheaper trim feeling, and a pretty narrow cabin. But I still really liked the car. Here in CT we get $3,000 above the $7,500 federal credit. So that's $10,500 off the list.

We drive a Kia Soul+ we love, but I can see myself buying a red Bolt just like I saw at the show. Looking forward to being a leading adopter. Of course, we'll be sure to keep a traditional car for longer trips. My feeling on the Bolt price is that you take the $27,000 price after rebates and start deducting the gas for three years ($1,500 a year). And essentially no maintenance. So I figure the real price of the Bolt is about $23,000 or so. Still more than my excellent Kia Soul+. But then I factor in the feel-good factor about driving an electric, and it might be a sale. Of course, that doesn't include delivery, and any options that might be must-haves.

Really quite impressed. More than I expected.

 

[oilerlord]

There are two Bolts on display at the Los Angeles auto show. I got to check it out pretty thoroughly and it looks really good

I had been concerned that it would be too small. It is smaller on the outside than my Focus was, but far more spacious inside. Great headroom in front and good in the rear. Plenty of rear legroom

Charging had some interesting options. One was the option to immediately charge to 40% and then to do a timed charge for the remainder. In essence this provides the option to use only the lower 40% of the battery charge window and provide 80 mile class range. This should be great for battery longevity

Another option was hill top reserve. The Chevy people were clueless about this but I bet this gives the option for hill top people to terminate charge early and regen on the way down rather than being forced to use friction brakes

The downers were things we already knew..,lack of homelink. Nobody could confirm resistive vs heat pump

Interior looked good to me. Leather seats were good looking

Rear storage area was much bigger than Focus but seemed smaller than Volt

All in all very nice. Confirms my plan to grab one

Thanks for checking it out.

I'm not surprised when dealers are "clueless" about EV's, but you'd think they would find some people that can answer questions about one at an auto show. I digress of course, but it brings back painful memories about shopping for EV's and having to deal with lot lizards.

I'm looking forward to the day I can take one out for a test drive. Cars always seem to look larger in pictures, but turn out to be smaller in person. I'm thinking that in a few years, I might buy a used Bolt either to replace or complement my B250e, but the Bolt's trunk looks pretty small compared to my car and could be a deal breaker. If you've sat inside a B-class, would you say the B is considerably larger inside, or about the same as the Bolt? Also, I read a review that was critical of the Bolt's interior:

"The cabin neither looks nor feels like that of a $40,000 car. It’s clear in the Bolt that most of your money is paying for that big brick of battery cells developed to live up to an eight-year, 100,000-mile warranty rather than luxury trappings. The seats are wrapped in economy-car-grade leather, and the door armrests are formed from an unpleasant hard plastic."

http://www.caranddriver.com/chevrolet/bolt-ev

I thought the Focus EV with leather interior was quite luxurious. Would you say the Bolt's interior is on par with your Focus?

 

[SeanNelson]

Battery University is well regarded, but it doesn't answer this specific question. The Army paper is the only one I have yet found that does.

It's important to understand that the difference in battery longevity between operating the battery in the 20-80 range vs. something like the 20-50 range is probably very minor compared to the reduction in longevity when operating it in the 0-100 range. So while there may be some advantages to restricting the range further than 20-80, in practice it's probably not going to make enough difference to be worth doing.

 

[michael]

.

Thanks for checking it out.

I'm not surprised when dealers are "clueless" about EV's, but you'd think they would find some people that can answer questions about one at an auto show. I digress of course, but it brings back painful memories about shopping for EV's and having to deal with lot lizards.

I'm looking forward to the day I can take one out for a test drive. Cars always seem to look larger in pictures, but turn out to be smaller in person. I'm thinking that in a few years, I might buy a used Bolt either to replace or complement my B250e, but the Bolt's trunk looks pretty small compared to my car and could be a deal breaker. If you've sat inside a B-class, would you say the B is considerably larger inside, or about the same as the Bolt? Also, I read a review that was critical of the Bolt's interior:

"The cabin neither looks nor feels like that of a $40,000 car. It’s clear in the Bolt that most of your money is paying for that big brick of battery cells developed to live up to an eight-year, 100,000-mile warranty rather than luxury trappings. The seats are wrapped in economy-car-grade leather, and the door armrests are formed from an unpleasant hard plastic."

http://www.caranddriver.com/chevrolet/bolt-ev

I thought the Focus EV with leather interior was quite luxurious. Would you say the Bolt's interior is on par with your Focus?

I'm not familiar with the Benz, so I can't help you there.

I would say the Bolt interior was in the same general class as the Focus, maybe a little short but not by much if at all. One nice aspect of the Focus was that except for leather and special paint, the base car already included every option. I also sat in a 2017 Focus Electric at the show and I wasn't struck by any feeling that moving to Bolt would be a downgrade in amenities.

In the case of my Volts, I think the decision to buy with the leather was a good one...to me it gives the car a feeling of being much more luxurious even without any other change.

The rear storage area of the Bolt is much larger than that of the Focus, big improvement there.

 

[oilerlord]

I'm guessing / hoping the Bolt is about the same size as the Ford C-max - which I consider the "right" size for me, and a car that I've always been impressed with - at least in hybrid form. If Ford would have somehow found a way to engineer the battery into the floor of the C-max Energi instead of it taking up so much of the trunk - I probably would have bought one. With that said, used Energi's are a steal.

Are you saying the "premier" trim doesn't have homelink? I could understand removing that option on the base car, but not on the high-end trim - especially on a $40,000+ car.

 

[JeffN]

Are you saying the "premier" trim doesn't have homelink? I could understand removing that option on the base car, but not on the high-end trim - especially on a $40,000+ car.

Homelink is also missing from the 2017 Volt and, I suspect, all or most other 2017 GM products. I have the impression it has also gone missing from some non-GM brands also. Maybe a licensing/pricing dispute?