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Some of you have seen the videos in this thread:

http://www.chevybolt.org/forum/10-technical-discussion/24505-how-remove-your-bolt-battery-big-one.html

In the videos, the sticker on the battery stated 57 kWh. The battery was disassembled and there were two types of battery modules (8 of ~5.9 kWh and the other 2 were around 4.7 kWh - Can't remember the exact numbers). Anyhow, when added up, it came to 57.02 kWh.

Why would Chevy state the battery is 60 kWh but it's really 57 kWh? Is the Chevy Spark battery specification higher than what the battery capacity is?
 

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Please note the key word here is "Rated", and that wording is applied by LG not Chevy. We don't know exactly what the parameters are for their rating. LG may be using a rating scheme where the top or bottom capacity of the battery isn't fully used, while Chevy has decided (after testing) to use more of the battery in daily operation. We just don't know.

I'll also point out that most batteries have a 'Nominal' voltage per-cell that is lower than the 'fresh off the charger' voltage. So if you measure battery rating using 'Nominal' voltage times amperage, you get a different number than if you use 'fully charged' voltage times amperage.
 

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Yes, I recently looked for a rule, a standard or a regulation that BEV manufacturers must use in stating their high voltage battery’s capacity. Couldn’t find one.

The Bolt’s Energy Detail kWh-used readout makes it look like Bolt has 60 kWh usable capacity. In addition to that there’s likely a buffer at the top and at the bottom for safety & longevity purposes.

One little clue I’ve observed: Immediately after you’ve charged to 100% “full”, you can still get regen kw's although limited to a max 32 kw in my test. As opposed to 60-70 max regen kw's when the SOC is much lower. When the battery is “full” (at top end cutoff threshold) don’t know if Bolt has capacity to “spill” excess unusable regen kw’s in the form of heat.
 

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Yes, I recently looked for a rule, a standard or a regulation that BEV manufacturers must use in stating their high voltage battery’s capacity. Couldn’t find one.

The Bolt’s Energy Detail kWh-used readout makes it look like Bolt has 60 kWh usable capacity. In addition to that there’s likely a buffer at the top and at the bottom for safety & longevity purposes.

One little clue I’ve observed: Immediately after you’ve charged to 100% “full”, you can still get regen kw's although limited to a max 32 kw in my test. As opposed to 60-70 max regen kw's when the SOC is much lower. When the battery is “full” (at top end cutoff threshold) don’t know if Bolt has capacity to “spill” excess unusable regen kw’s in the form of heat.
I've wondered about this too. With my commute I have to charge to 100% and for the first 10-15 miles, the regen symbol is grayed out instead of green. It says regenerating but I think it's actually "spilling" it over until the symbol turns green. I don't know for sure but I actually have to touch my brakes a couple of times in the first couple of miles so I notice the change for sure.
 

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With the large variability of range miles based on temperature, terrain, technique, and climate control use, does it really matter whether it is 57+ or 60 kWh? We all hope to never run out of juice, and plan & drive accordingly. I have gotten 260 miles on a full charge and 170 miles on a full charge. If you charge nightly, it doesn’t matter at all. If I plan a long distance trip (232 miles was my longest planned single-charge leg) I like to arrive with a comforting reserve. I slow down and extend my range.
 

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I may have joked before about HDD size convention (kilobyte's 1000 vs kebibytes 1024) being used on our battery in the other thread, but I would be a little sour that GM sold us on 60 kWh when really there's only 57 kWh. I haven't watched the battery disassembly video yet, but if all the individual modules do add up to 57 kWh, that's annoying. I'd much prefer to be told I can drive 57 kWh-worth and actually drive it than be told I can drive 60 kWh but actually only get 57 kWh before the battery pack protection kicks in to avoid me bricking the battery pack.
 
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Frankly, I don't care - all that matters is how far I can go. One of the bragging points for the Ioniq EV is that it has the highest MPGe of vehicles sold in the U.S. (or so they say). If it had a 55 kWh battery (which it doesn't) then its range would be further than the Bolt's range. I'd care more that it could go (say) 260 miles (vs. 238) on a full charge, than the fact that its capacity was 55 kWh instead of 60 (or 57).
 

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I may have joked before about HDD size convention (kilobyte's 1000 vs kebibytes 1024) being used on our battery in the other thread, but I would be a little sour that GM sold us on 60 kWh when really there's only 57 kWh. I haven't watched the battery disassembly video yet, but if all the individual modules do add up to 57 kWh, that's annoying. I'd much prefer to be told I can drive 57 kWh-worth and actually drive it than be told I can drive 60 kWh but actually only get 57 kWh before the battery pack protection kicks in to avoid me bricking the battery pack.
the labels on the batteries were 5.94 kWh x 8 and 4.75 kWh x 2 = 57.02 kWh
 

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I'd much prefer to be told I can drive 57 kWh-worth and actually drive it than be told I can drive 60 kWh but actually only get 57 kWh before the battery pack protection kicks in to avoid me bricking the battery pack.
In what way have you been sold short? IMHO, you would have no idea what "57 kWh-worth" would mean, until somebody would translate that for you into "achievable distance in relation to driving style / circumstances, blablabla". Once knowing that achievable distance, does it matter hoe big the battery is? As a matter of fact, with the battery being smaller than thought, the car turns out to be more energy efficient than you had thought. Cool thing, right?

Imagine, a normal ICE car being advertised as "being able to drive 600 miles on one tank of gas". Now if you have to choose, would you prefer to discover that the tank was bigger than advertised or would you prefer to discover that it was smaller than advertised? Personally, I think I would be more annoyed if it was the other way around: if the battery turned out to be 3 kWh bigger, and the advertised range turned out to be achievable only after putting 63 kWh into the battery instead of 60 kWh. As it would make the car more expensive to drive, than I had anticipated based on the specs.
 

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There must be some esoteric math or rationale that GM and LG are using that insulates them from lawsuit about this. I find it hard to believe that they would unwittingly receive a 57kwh battery from LG and call it 60kWh. That would leave them widely open to a class action lawsuit, even if said lawsuit never gained traction it would be pretty bad press that they open lied about 3kWh.

So, there is something going on that only an deeply embedded LG and GM engineer would know as to why they can technically say its 60kWh when the label on the actual battery pack and modules within clearly say or add up to 57kWh.
 

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All OEM traction batteries are top balanced. Any variability in actual cell capacity shows up at the bottom of the charge. Perhaps the original spec said all delivered cells must be at least X capacity, based upon an agreed upon maximum, and minimum voltage. If it turned out the supplier could not provide the necessary number of cells to that spec due to raw material quality, or manufacturing system problems, driving cost up, or production down, then it is conceivable that the spec was lowered to meet production goals.

If the original spec left GM more buffer to reach the warranty lifetime goal, that would be a longer range concern. If they couldn't get the cars out, that would be a much nearer term problem.
 

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The original LEAF with a 24 kWh battery actually had 21-22 kWh useable.

That is a much bigger deal than 57 vs 60.

The 57 kWh Bolt is a CAR....the 22kWh LEAF was a finite distance transportation appliance.

At 75 mph on the highway in winter....the LEAF would only 'go' for about 35 minutes!
 

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Yes, I recently looked for a rule, a standard or a regulation that BEV manufacturers must use in stating their high voltage battery’s capacity. Couldn’t find one.

The Bolt’s Energy Detail kWh-used readout makes it look like Bolt has 60 kWh usable capacity. In addition to that there’s likely a buffer at the top and at the bottom for safety & longevity purposes.

One little clue I’ve observed: Immediately after you’ve charged to 100% “full”, you can still get regen kw's although limited to a max 32 kw in my test. As opposed to 60-70 max regen kw's when the SOC is much lower. When the battery is “full” (at top end cutoff threshold) don’t know if Bolt has capacity to “spill” excess unusable regen kw’s in the form of heat.
No they just modulate the IGBT trasistors to only load the motor to 32kw and present that to the cell pack. Its just the reverse process to the accelerator. so there is no spillover.
 

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The original LEAF with a 24 kWh battery actually had 21-22 kWh useable.

That is a much bigger deal than 57 vs 60.
I cannot imagine the label on the battery would inform us on the "usable" capacity as, IMHO, that is a function of the BMU software, not the battery itself. So, for the Leaf you are comparing "total" with "usable". Where, if I am not mistaken, for the Bolt we are now comparing "advertised capacity" with "actual capacity". Apples and oranges perhaps? It could be that "usable" for the Bolt is even lower.
 

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A good point, but I still think that most buyers are equating 'advertized' with 'useable' rightly or wrongly.

So, any idea what 'actual' is for a new Bolt??
 
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