If you've just become a new owner, congratulations!
There are some questions (and misconceptions) that seem to come up over and over. In general, before asking about something, it doesn't hurt to search the forum (or check out the other Bolt FAQs that exist, such as this one on reddit
One recurring new-owner concern relates to the (mistaken
) idea that the battery contains “miles” and that when fully charged, the readout should say 238 miles for a 2017–2019 Bolt, and 259 miles for a 2020 Bolt because that's what Chevy lists as the full-charge range.
Digging a bit deeper:
The Bolt's estimated
range is shown by the numbers on the lefthand-side display of the dash, often referred to by longtime Bolt fans as the GOM, or Guess-O-Meter. The car uses your recent driving to guess
how far you might be able to drive given your recent driving efficiency (and I mean recent
as in a weighted average based the last 50 miles or so, and certainly not the last 4451.9 miles displayed by the car in the picture above).
- If your recent efficiency is about 4 miles/kWh, the 100%-charge range will be 238 miles for a 2017–2019 Bolt, and 259 miles for a 2020+ Bolt.
- If your recent efficiency is about 3 miles/kWh, the 100%-charge range will be 178 miles for a 2017–2019 Bolt, and 194 miles for a 2020+ Bolt
- If your recent efficiency is about 5 miles/kWh, the 100%-charge range will be 298 miles for a 2017–2019 Bolt, and 324 miles for a 2020+ Bolt
The same is true for any car. A gasoline car (which these days can often show estimated range as well) can drive further on a full tank when driven efficiently compared to driving it inefficiently.
New Bolt owners often take some time adjusting to the estimated range being displayed so prominently and the guesses about the range varying over time. There are often threads like “I used to be able to charge my car to 238 miles and now it only can charge to 178 miles! Is there a problem with my battery?!?” (due to efficiency dropping). Strangely, perhaps, there are fewer occasions where people post about the opposite, where the range increases due to efficient driving. In contrast, gasoline cars don't tend to display their range so prominently, and probably most owners wouldn't think their gas-tank had suddenly shrunk if the estimated range dropped after hard driving.
I think part of what causes confusion is that the miles number draws people's eyes, and they think it represents the battery's state of charge. But if you want to know how much charge is in the battery, that is not what you should be looking at.
Note that this display is only accurate to the nearest 5% and rounds up
, so seeing all 20 bars means your state of charge is somewhere between 95.1% and 100%. Only when you drop down to ≤ 95% will the top bar disappear.
Charging to 100% Limits Regen
If you charge your Bolt to 100%, regenerative braking is limited.
In this example, the car is only going to allow about 20 kW of regenerative braking (light braking) rather than the full 70 kW.
The easiest way to avoid limited regen is to set the car to only charge to about 90% full. In early Bolts, this is the “hill-top reserve” feature, which is fixed at about 88%, and in later Bolts you can choose a percentage. Not charging to full is slightly better for the battery, too, but the jury is out as to whether the benefits will ever be detectable for most owners.
People are often confused about this because the car decides how much to limit regen, and various factors enter into the decision. For example, it can also limit regen when the battery is very cold or hot. But if you charge to 100% and let the car sit a while, the battery will have settled a bit and the car will be more generous in what it allows. This leads to very different anecdotal accounts of how much regen is available when charged to full, some people say there is plenty, and others say there is almost none at all. The truth is it's situational, but the car's display tells you how it is.
Some people think that there couldn't be room for any regen at all 100% charge, but 10 seconds of regen at 20 kW is about 0.05 kWh, or adding less than 0.1% to the battery. Also, the “100%” point for the battery is arbitrary (a particular voltage to charge up to and not beyond). The car could in principle charge the battery to 110% or discharge it below 0%, it would just wear it out prematurely to do so. GM (and LG) picked the 100% and 0% points in a trade-off between battery life and battery capacity.
If you learn one thing from this post, it's that the battery doesn't contain miles
(so the range display is not showing you battery capacity
Actually, to be pedantic, the battery doesn't even contain kWh, although we usually like to pretend it does. It contains chemical potential energy that is converted to electrical current at a particular voltage, and the only real way to know how much usable energy it contains is to drive the car and see how much you got out. If you drive from 90% down to 23% and used 40 kWh, you've used about 2/3 of the battery's capacity (90% - 23% = 67%) and you can estimate the full capacity at 60 kWh (40/0.67 = 59.7). (But even there, the estimate is for whatever style of driving you were doing, because how much energy you get out of a battery depends on the discharge rate, so you'll get more kWh out driving slowly with modest demands than driving hard.)