Wish List -- things I really want to see in the Bolt

1) A secure way of knowing remaining battery capacity including history that is easy to access.

Secure, meaning can't be reset by a used car dealer or anyone else. A history makes events like a new battery install transparent to the potential buyer of a car. Must be accessible from the center console without special tools or software at minimum.

If I want to buy or sell an electric car, I need to know what the best estimate of the battery capacity is. Sure, I know that all measurements are not exact, so having either a stated accuracy (56 kWh plus or minus 2 kWh) or a minimum estimate (54 kWh, maybe more, but not less) is acceptable.

If I'm buying a car, I need to know what I'm buying. If I'm selling a car, I'll get a better price if the buyer can trust what I'm selling. A large fraction of the value of a EV is the battery pack condition. (23% of a new Bolt?)

That is an excellent point to be able to access the history and still available capacity of the battery is definitely a wish list item if not I must

2) An easy way to put the car in "long life" battery mode, with an equally easy way to switch to "long range" mode.

There are many things that can be done to protect a battery. After driving a Leaf for 4.5 years, I've come to do many of them manually. For instance, keep the state of charge near 50% as much as possible. Don't charge when the battery is hot. Etc. Of course these limit when you can charge (ideally, run the TMS until the battery is cooled off before starting to charge at all), and how far you can travel (if you don't charge to 100%).

These modes should be explained to the owner, and should be easy to select from the center console.

Ideally, the "long life" mode is ultra conservative.

GetOffYourGas said:

2) An easy way to put the car in "long life" battery mode, with an equally easy way to switch to "long range" mode.

There are many things that can be done to protect a battery. After driving a Leaf for 4.5 years, I've come to do many of them manually. For instance, keep the state of charge near 50% as much as possible. Don't charge when the battery is hot. Etc. Of course these limit when you can charge (ideally, run the TMS until the battery is cooled off before starting to charge at all), and how far you can travel (if you don't charge to 100%).

These modes should be explained to the owner, and should be easy to select from the center console.

Ideally, the "long life" mode is ultra conservative.

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I think you'll find most of that totally unnecessary. The Achilles heel and root of most of the LEAF battery woes are the completely passive cooling system (and the battery chemistry - more so on the older models). On the Volt, GM was very conservative on how much of the pack was available (essentially keeping it in "long life" mode all the time). They even got some criticism for being too conservative. I expect a similar approach on the Bolt.
Wwith 3 separate cooling loops - one dedicated entirely to the battery- they can manage temps very closely. It's far better for the battery to keep it from getting too hot in the first place, rather than worrying about letting it cool before charging.

The Fit EV is air cooled (fans, but no liquid cooling loop) and there have been zero reports from any owner of any range loss at all. I've had mine for 2 1/2 years and get the same range as when new. We never do anything at all to baby the battery. Keep it fully charged all the time, top off even when 80% full, etc. It will probably even get plugged in immediately tonight even though it will be about 100 degrees out.

Active Thermal Management - don't leave home without it

Edit: I also think that kind of thing is a huge turn off to most drivers. If they want a true mass market car, people need to be able to drive and charge without having to decide ahead of time if 80% charge is enough. Is the battery cool enough to charge, etc. Plug it in when you get home. Unplug and drive in the morning. Anything different and my wife (for one) would not drive an EV.

Two things. First, the Bolt's TMS is not as robust as the Volt's. I hope GM didn't cut the corner too tight and it I still adequate. I will give them the benefit of the doubt though unless and until I know otherwise.

Second, there is no way the Bolt will be as conservative with the state of charge as the Volt. It will charge higher and discharge lower. You can count on that. It has to. It has no gas generator backup. Assuming a typical 4 miles per kWh, it must have 50kWh usable of 60kWh total. Yes heat is a bigger killer than high/low state of charge. But the latter still matters.

As for ease of use, one could argue that ideally you'd want a battery that didn't need the cost, energy use, and complication of a TMS in the first place. But that is not the state of technology. We have to work with the technology we have, not that which would be more appealing to your wife.

GetOffYourGas said:

Second, there is no way the Bolt will be as conservative with the state of charge as the Volt. It will charge higher and discharge lower.

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The batteries on most Volts are "completely" charged and discharged on a regular basis because people simply use the ICE to drive beyond the battery range. Whereas on the Bolt "complete" discharges are going to be a rarity, because people hate getting down into that last 20% or so with the attendant range anxiety. And in fact because of the Bolt's long range there's going to be less of a delta between the typical discharged and fully charged percentages compared to other, shorter-range EVs.

Simply by having such a big battery the Bolt is already going to be abusing it less, especially compared to the Volt.

GetOffYourGas said:

2) An easy way to put the car in "long life" battery mode, with an equally easy way to switch to "long range" mode.

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There other reason to want to control the charging level on an overnight charge. I live near the top of a hill. I'd like to have regeneration available right away, so would prefer to charge to usually less than 100% (100% being the fullest the battery can get), and other times I might want to have a completely full battery.

I don't want a mode, just a "charge to this level" (perhaps 50% to 100% by 5% steps?) someplace in the center console.

3) A real battery temperature readout in degrees C and F. Sure, the TMS should be taking most of the temperature worries away. I'd like to know the actual battery temperature when driving up and down steep mountain roads, on long trips with multiple DCQC sessions, etc.

Ideally this should be a driver display, but I'd accept a center console screen with this and other "engineering details".

4) Socialize the car. Provide a way to record trips similar to Leafspy.

Perhaps just a bluetooth to cellphone link with an open API for third parties to write cellphone apps. Or perhaps using the car's cellphone link. Or even something else. Technology matters less than ease of use.

I like the ability to show someone my trips, where, when, battery charge level, outside temperature, battery temperature, ... Think of it as a social link to the car, making the car worth more to the owner, and more attractive to non-owners. Allow me to automatically fuzz out exactly where my home is, and perhaps other points where the trips start and/or end, for security and safety.

SeanNelson said:

The batteries on most Volts are "completely" charged and discharged on a regular basis because people simply use the ICE to drive beyond the battery range.

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Well no, not really. This statement is misleading at best. The original Volt only allows the driver to us about 2/3 of the total capacity, neither fully charging nor discharging the battery at any time. I know they have widened the window, but I guarantee it is narrower than the Bolt will be.

SeanNelson said:

Whereas on the Bolt "complete" discharges are going to be a rarity, because people hate getting down into that last 20% or so with the attendant range anxiety. And in fact because of the Bolt's long range there's going to be less of a delta between the typical discharged and fully charged percentages compared to other, shorter-range EVs.

Simply by having such a big battery the Bolt is already going to be abusing it less, especially compared to the Volt.

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This much is true in general. But the bolt's battery will therefore sit at a much higher average state of charge which is stressful for it. And that is exactly my point.

GetOffYourGas said:

This much is true in general. But the bolt's battery will therefore sit at a much higher average state of charge which is stressful for it. And that is exactly my point.

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So what's worse for a battery over a given period of time: more cycles or storage at a higher state of charge?

I suspect the former, that the cycle count matters more.

Storing at a high level is bad for the battery. Actually cycling it between moderate levels is benign.

Get off your Gas is right on point. A big complaint I have with my Focus electric is the inability to set a maximum charge level. The only way to stop the charge is to walk outside and unplug it. Ridiculous for a car that's one big computer.

It's true that a problem with Leaf was its lack of effective battery cooling, but it is well documented (Jeffrey Dahn, for example) the deposition and loss of lithium happens mainly at high temperature and at high charge levels. A battery that is rarely charged to high SOC and is kept cool will last a long time

It is also well documented (NREL) that "just in time" charging increases battery life by not forcing the battery to sit a high SOC

It seems to be true that the lithium titanate batteries (Toshiba) in the Honda FIT EV show very good life, but it also seems to be true that they fall on their faces in cold weather. There ain't no free lunch. Every battery chemistry has advantages and failings.

A long life mode (reduced charge level, lower battery temperatures) and a performance mode (fuller charge, higher temperatures) is simply a software change. Manufacturers should provide this. Tesla comes close, with at least the ability to set target charge level.

michael said:

A long life mode (reduced charge level, lower battery temperatures) and a performance mode (fuller charge, higher temperatures) is simply a software change.

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Choices with wide impacts.

Warranty, for example. If you keep the car in performance mode all the time, does this void or reduce your battery capacity warranty?

This could be a lot more complex than just two modes. More modes, or more control over TMS and BMS setpoints would be interesting to the more techo geeks. Having this kind of control appeals to me, but I'm not sure how wide the appeal would spread. Electric cars, to become more popular, need to stay as simple as reasonable to the driver.

There is no warranty against battery fade, so it's irrelevant.

There is no impact to warranty if you drive an ICE car at full throttle all the time or at granny speeds.

The Toyota RAV-4 EV, for example, does offer "standard" and "extended" charge. if you select extended, a message appears on the screen reminding you that battery life may be shortened. That's plenty.

I'm not suggesting a "turbo" battery killing mode be added. I suggesting a second battery saving mode be provided as well. That's what's missing on my Focus. That's what used to be on Leaf until Nissan realized they could game the mileage rating by removing that option.

Yes, it could be more complex but two modes are all I'm asking for, I'd settle for that rather than just one.

michael said:

There is no warranty against battery fade, so it's irrelevant.

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That's news, if true. Nissan has a capacity warranty, if GM doesn't they will lose sales.

WetEV said:

michael said:

There is no warranty against battery fade, so it's irrelevant.

Click to expand...

That's news, if true. Nissan has a capacity warranty, if GM doesn't they will lose sales.

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I bet GM will only lose sales to jaded ex-Leaf drivers. Most EV buyers are unaware of capacity fade in the first place, and won't notice the lack of warranty.

Now if, 5-10 years down the road, Bolt show significant battery degradation, GM will have a problem. Today GM does not warranty the capacity of the Volt's battery, but nor have they had to. To date, there is no noticeable loss of range.

A heat pump for cabin heat.

A "supercharger" option that allows Bolt owners to access the Tesla Supercharger network. That, and seeing pigs fly.

OK, a geeky request.

Dynamic battery balancing.

The usual way battery packs in BEVs are balanced is "top balancing". Charge all the cells to the same voltage by use bypass resistors to "balance" the pack by switching in the resistors to discharging the cells that have higher voltages. While discharging, the pack takes the exact same current out of each cell, when the cell with the smallest capacity and thus the lowest voltage hits a lower limit the pack is empty. Notice that the cell with the smallest capacity sets the limit for the pack, and the cell with the smallest capacity is working the hardest and thus will have the most cycling wear.

Dynamic battery balancing, by one of several methods, keeps the voltage in the cells the same as they are discharged. This levels the cycling wear on the pack, and reduces wasted energy in balancing resistors, and provides more usable capacity, especially as the battery pack ages.