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After three months of ownership I noticed that with a full charge driving in L mode reverts to D mode driving characteristics. This essentially means no one pedal driving. I understand this is likely due to no regenerative capacity available. However, i believe the driving characteristics should still reflect the L mode for consistency and safety.
 

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Unfortunately there is no way to do that...and unless you actually need the range recommend you only charge to 90% (hilltop reserve active) - keeping LiOn batteries at 100% shortens their life span...
 

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Unfortunately there is no way to do that...and unless you actually need the range recommend you only charge to 90% (hilltop reserve active) - keeping LiOn batteries at 100% shortens their life span...
:eek:I've never heard of "hill top reserve" prior to the Bolt EV. My previous BMW i3 had no such feature. How about Tesla? Don't all EV batteries utilize less than 100% capacity, just for that reason? "Keeping Li Ion batteries at 100% shortens their life span?" Over what time frame? My Bolt is a lease, and I'm only concerned over a 36 month period. When I return my Bolt at lease end, it will be in excellent condition as I take care of all my possessions. I feel confident the battery pack will be fine. When I fill a ICE vehicle, I fill it up. The same with my Prius Plug In, my previous i3, and current Bolt. Full is full. I'm a consumer, not a scientist. My Bolt doesn't need to be protected from my way of thinking.
 
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When he battery is at 100% (or close to) it is not possible to have L drive like it does once you are lower in charge. The regen brakes need to send the generated electrons somewhere, it can't just create them and eat them. When the battery is full it can't be sent back to the battery as overgharging li-ion batteries is pretty much the worse thing you can do to them. So while at 100% or close to it regen braking will be reduced significantly. If you always want regen braking to be there soon as you drive you should change your charge mode to Hill-Top reserve like David suggested.


Far as keeping the li-ion battery at 100%. Yes it can shorten the lifespan of li-ion battery cells. However you really need to leave it at 100% for long periods of time to do real damage to it. If you are just charging to full each night and then using the Bolt the next day it isn't going to be significant damage. I mean we are talking in the single digits of battery capacity degradation over years of use. So I wouldn't freak out about it. However if you are recharging each night and you don't need or use the full range each day using hill-top reserve is probably advisable. Keeps the battery at a max charge of around 87-90 percent. This has two benefits. Doesn't keep the li-ion battery at 100% helping with its longevity and if you drive in L you will have full regen from start.
 

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100% charge means different things.

When you charge to 100% SOC as shown by the car (usable capacity), you are actually charging to less than the full potential battery capacity (actual pack size). All EV's limit the charge to something less than and keep both a lower and upper buffer to prolong battery life. No exact figure is available as to the "real" pack size on the Bolt, but it is certainly greater than the 60 kWh that is available. Some manufacturers report actual pack size, some report usable capacity, some report both. GM reports usable capacity (340 V x 171.4 Ah = 59.99 kWh).

How well the Bolt battery holds up when used as prescribed by GM can only be definitively answered years from now. The reported effect of full charging damage to a battery has many roots, the original LEAF being one of the primary. Early versions of the LEAF had the option of 100% charge (Long-Distance Mode charging) and 80% charge (Long-Life Mode charging). Nissan was likely aware of the implications of a passively cooled battery and the particular chemistry they were using. After the EPA decided that the "official" range would be the average of the two, Nissan dropped the 80% charge mode so the EPA label would show 84 miles instead of the "blended" 75 miles.

There was a recent report of a 400,000 km (250,000 mile) model S with 7% battery degradation. The routine level of charge was not specified in the report (Teslas have a "slider" where you can set to % you want), but it is a taxi and I find it highly unlikely that less than 100% would be the norm.

But to the OP's question/observation:
Having consistent regen behavior could certainly be a desirable feature, and we may see it incorporated in the future. In order to do it, they would either need to engage the friction brakes or apply power to the motor in "reverse" to slow the car. Both go against the grain of engineers looking to preserve and recapture every electron, but in reality requiring the driver to apply the friction brakes to slow/stop the vehicle has the same result. While a full "tank" is the most common cause of regen reduction, battery temp can also be a cause (but to a lesser extent). There is a lot to be said to having the car behave in a consistent manner when "shifting" into L or just lifting off the go pedal while in D (regen is also reduced in "D" at 100% SOC, but it is less noticeable).

Or people will just get used to it as normal behavior for an EV or routinely charge to less than 100% (hilltop reserve, etc) if maximum range is not required.

Bigger batteries change things. Routine charging to less than 100% is more practical. Range anxiety with 40 miles remaining (the total range of early EV's with degraded batteries or in cool temps).
 

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100% charge means different things.

When you charge to 100% SOC as shown by the car (usable capacity), you are actually charging to less than the full potential battery capacity (actual pack size). All EV's limit the charge to something less than and keep both a lower and upper buffer to prolong battery life. No exact figure is available as to the "real" pack size on the Bolt, but it is certainly greater than the 60 kWh that is available. Some manufacturers report actual pack size, some report usable capacity, some report both. GM reports usable capacity (340 V x 171.4 Ah = 59.99 kWh).
DucRider is most likely correct. I don't remember which post it is but somewhere someone took the space available in the battery pack and the known size of the cells used in the Bolt's battery and came up with a possible capacity of 65.99 kWh (if the area of the battery pack was filled to capacity). So it is quite possible and even likely that the battery in the Bolt is larger than 60 kWh to protect it from sitting at a true 100%. I didn't mention it because even if the battery pack is larger than 60 kWH they programmed the Bolt to treat that level of charge as 100%. Thus is doesn't allow full regen braking as to not go over that charge level. I of course can't say he is definitively correct because GM won't say the true capacity of the Bolt battery and i'm certainly not taking mine out to count the cells, lol. Also his points about battery temperature and regen braking are also correct, the higher the temp the less charge it will allow to go in, high heat is probably the biggest threat the battery longevity next to overcharging. Since the Bolt has active cooling though it shouldn't be much of an issue. I've already done a long trip in temps over 100 degrees and I felt no difference in the regen braking, seemed to be acting exactly as I was accustomed to. There is a grey line that appears where the regen meter is on the right of the display that will show how much regen is allowed to occur. Isn't super obvious though.


Far as being concerned about the lifetime of the battery (short of defects of course) In wouldn't be that concerned. Here are a few videos that talk about Tesla and their batteries using a ton of data collected from Tesla owners. Some of them have driven ridiculous amounts of miles and aren't seeing any crazy amounts of degradation. There is also a page where you can see all of the data in spreadsheet form or using a visualizer. I know this isn't about the exact battery in our cars, but it is about li-ion batteries in a car so I think it is safe to assume we should see similar statistics over time. One guy even did an experiment with the older cells Tesla used and only found that they lost .35% per year of capacity while sitting around.


https://teslanomics.co/what-is-the-lifespan-of-a-tesla-battery-and-how-long-will-it-last

I think the data we have to wait and see though is the reliability of the cells GM used in the Bolt battery pack. That will take years to get the right data on.
 

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When he battery is at 100% (or close to) it is not possible to have L drive like it does once you are lower in charge. The regen brakes need to send the generated electrons somewhere, it can't just create them and eat them.
Technically speaking, it's possible to include load-shedding resistors that would accept the regenerated power and convert it to heat, thus simulating "regen" when the battery is too full to accept more charge. This is something that's done in some electric trolley buses, for example. But it would be an added cost and hasn't been implemented in the Bolt.
 

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To answer the OP's question:

Teslas have charge control from 50-100% setting - 90% is the "Daily" setting and the slider will snap to that setting to make it east to set - values above 90% are in the "Trip" range, if you set your charge to 100% and charge that way for several charge sessions Teslas software warns you about this setting and ask if you want to keep charging to 100% and recommends a lower setting to prolong battery life.

High mileage Teslas are showing some percent loss on Range after several 100,000 miles but nothing extreme or unmanageable, and so far all in line with expectations.

While it is probably ok to charge to 100% each day if you don't need the range there should be no downside to using hill-top reserve and it will prolong the battery by some minor percentage, it also means you have regen right away after charging the car!
 

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Technically speaking, it's possible to include load-shedding resistors that would accept the regenerated power and convert it to heat, thus simulating "regen" when the battery is too full to accept more charge. This is something that's done in some electric trolley buses, for example. But it would be an added cost and hasn't been implemented in the Bolt.
Yes, that is certainly possible. I was only commenting about what the Bolt is capable of. If you turn kinetic energy into electrical power it then has to go somewhere. If super capacitors were cheaper it would have been possible to have some in the car for the purpose of energy capture thus allowing a more forgiving regen brake system. I can't imagine any manufacturer would want to add all the extra weight and heat generated from load-shedding resistors, while feasible it may be, just seems like a lot of extra complication for what is a short term problem. You only need to get the battery down 5% or so before regen kicks into full.

You mentioning load-shedding resistors makes me want to go looking for something though. A few years ago there were some breakthroughs on the opposite of those. Tech that is able to take heat energy and turn it into electrical. I wonder how much further that has come along. I mean when I saw it was just some academic papers, not commercial stuff yet.
 

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We charged our Bolt up to 100% for the first time Tuesday, to get the cells to top balance. I figured if GM is monitoring our battery, this will be necessary information for them to assess its condition. I knew that the regen would be reduced. I drove around for 14 miles in L. It functioned totally normally. Bringing the car to a full stop at stop signs. I suspect, if I had pushed it above the speed limit, and waited to the last second to stop, I would have seen a reduction in regen. But for normal driving, on secondary roads, it worked just fine. This shows that GM is not charging these cells to 4.2 volt at 100% charge. They are probably stopping at 4.1 volts.
 

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We charged our Bolt up to 100% for the first time Tuesday, to get the cells to top balance. I figured if GM is monitoring our battery, this will be necessary information for them to assess its condition. I knew that the regen would be reduced. I drove around for 14 miles in L. It functioned totally normally. Bringing the car to a full stop at stop signs. I suspect, if I had pushed it above the speed limit, and waited to the last second to stop, I would have seen a reduction in regen. But for normal driving, on secondary roads, it worked just fine. This shows that GM is not charging these cells to 4.2 volt at 100% charge. They are probably stopping at 4.1 volts.
It does still do some regen even at full charge. Next time you do a full charge and drive look at the area that shows the regen amount on the right side of the drivers display. There will be a light gray line that shows the maximum amount if can use of the regen brakes. As you drive and use the battery that line will gradually get down to the bottom part of the display indicating that the regen brakes are full operation.
 

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Neat! I will look for that. I don't intend to fully charge more than once every month or so, as we are hardly tapping the battery's range even at 90%.
 

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Neat! I will look for that. I don't intend to fully charge more than once every month or so, as we are hardly tapping the battery's range even at 90%.
Yeah, I almost never charge to 100%, only when I think I may need closer to the max range.

So I think I have done only 3 or 4 100% charges.
 

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I have owned my Bolt for exactly three months and have consistently charged to 100% for the entire time. I'm in a different situation than most on this forum in that I am retired and only drive the car once or, at the most, twice a week and only for relatively short distances (12 to 25 miles at a time). My odometer is currently at 290 miles total. The car is parked in my garage plugged into a level 2 charger when not being driven. I have been very pleased so far with the Bolt and after following this discussion have decided to change the energy settings to Hill Top Reserve instead of charging to 100% to try to lengthen the life of the battery. Thank you for this helpful information.
 
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