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oilerlord
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Re: "Full" battery levels dropping daily

Thu Nov 09, 2017 5:27 am

LOLady wrote:

I am not talking about longer term degradation of the battery. I am talking about the "full" level being 40-50 miles less on a rather sudden basis. The car is only 6 months old


Most modern cars (not only EVs) have range remaining displays. We commonly refer to the ones in our EVs as "guess-O-meters" because it's essentially what they do. They estimate / guess at range remaining based on your recent & real-time driving.

To SparkE's point, if you drive the same routes, the same speed, and at the same ambient temperature and wind conditions - the range remaining estimate can be quite accurate. They can also be notoriously inaccurate (and guess) at remaining range if your driving habits and environmental conditions fluctuate, or if other people drive your car. My range meter can fluctuate up to 50% based solely if my wife drives our EV, or if I do. It sounds crazy, but this is normal. There is nothing wrong with your car.
2014 Mercedes B-Class Electric Drive
2012 VW Jetta Sportwagen (not-so-clean-diesel) TDI
2008 BMW X3 3.0 "Beatrice"
2004 BMW 330Xi Sedan
My 9.2kW DC Solar: https://easyview.auroravision.net/easyview/index.html?entityId=7466210

boltage
Posts: 383
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Re: "Full" battery levels dropping daily

Thu Nov 09, 2017 6:27 am

oilerlord wrote:
LOLady wrote:

I am not talking about longer term degradation of the battery. I am talking about the "full" level being 40-50 miles less on a rather sudden basis. The car is only 6 months old


Most modern cars (not only EVs) have range remaining displays. We commonly refer to the ones in our EVs as "guess-O-meters" because it's essentially what they do. They estimate / guess at range remaining based on your recent & real-time driving.

To SparkE's point, if you drive the same routes, the same speed, and at the same ambient temperature and wind conditions - the range remaining estimate can be quite accurate. They can also be notoriously inaccurate (and guess) at remaining range if your driving habits and environmental conditions fluctuate, or if other people drive your car. My range meter can fluctuate up to 50% based solely if my wife drives our EV, or if I do. It sounds crazy, but this is normal. There is nothing wrong with your car.


The distance to empty displays in liquid fueled vehicles are not conceptually different, and are subject to the same fluctuations based on how efficiently the vehicle has been driven recently. However, some specific situations can affect electric vehicles and liquid fueled vehicles differently. For example, cold temperatures may lead the user to use the cabin heater, which is basically free in a liquid fueled vehicle, but expensive in an electric vehicle (seat heaters are much less expensive). On the other hand, driving down a hill in an electric vehicle can increase the mileage remaining, due to the potential energy at the top of the hill being regenerated into the battery.

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oilerlord
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Re: "Full" battery levels dropping daily

Thu Nov 09, 2017 7:06 am

Not conceptually different, just that the fluctuations are more severe with an EV than they are with a petrol based vehicle. If I drive my TDI at 50 MPH or 75 MPH, the difference in efficiency is about 7 miles per gallon. With it's 15 gallon tank, that's (roughly) the difference between getting 700 miles or 600 miles respectively, or a fluctuation of about 14%. Drive an EV at 75 MPH vs 50 MPH, and the fluctuation may be dramatic. Just a guess, but at a constant 50 MPH, I'd think the Bolt is capable of nearly 300 miles. At 75 MPH, I doubt it would be able to break 200. I think it's these fluctuations that gave rise to the term "guess-O-meter".
2014 Mercedes B-Class Electric Drive
2012 VW Jetta Sportwagen (not-so-clean-diesel) TDI
2008 BMW X3 3.0 "Beatrice"
2004 BMW 330Xi Sedan
My 9.2kW DC Solar: https://easyview.auroravision.net/easyview/index.html?entityId=7466210

gpsman
Posts: 351
Joined: Thu Oct 20, 2016 9:10 pm

Re: "Full" battery levels dropping daily

Sat Nov 11, 2017 9:50 pm

I have done as close to a scientific measurement as possible.

I went an entire “tank” at 3.9 to 4.0 miles per kWh.
(3.96 miles per kWh is the EPA rating of 238 miles per full charge.)

Then I did a full charge.

When new, this = 238 miles.

Now, at 10 months and 10,400 miles, I get 234 miles.
A loss of 4 miles, which I attribute to age.

A loss of roughly 2% in roughly 10,000 miles.

If this keeps up (2% per 10,000 miles, 20% lost per 100,000 miles) that is pretty good.

At 100,000 miles on the odometer, it is resonable to expect .80 x 238 or 190 miles of range, when driving at an average of 3.9 miles per kWh.

discodanman45
Posts: 2
Joined: Sun Apr 16, 2017 8:29 pm

Re: "Full" battery levels dropping daily

Mon Nov 13, 2017 2:44 pm

gpsman wrote:I have done as close to a scientific measurement as possible.

I went an entire “tank” at 3.9 to 4.0 miles per kWh.
(3.96 miles per kWh is the EPA rating of 238 miles per full charge.)

Then I did a full charge.

When new, this = 238 miles.

Now, at 10 months and 10,400 miles, I get 234 miles.
A loss of 4 miles, which I attribute to age.

A loss of roughly 2% in roughly 10,000 miles.

If this keeps up (2% per 10,000 miles, 20% lost per 100,000 miles) that is pretty good.

At 100,000 miles on the odometer, it is resonable to expect .80 x 238 or 190 miles of range, when driving at an average of 3.9 miles per kWh.


The only way that would be scientifically useful is if you did that experiment a few thousand times and had all the same variables. Temperature, air density, wind speed, tire pressure, travel route, car weight, etc... would all have to be the same. That "loss" of 4 miles could just be within the error bars of your experiments.

Now lets say you did lose 2%, which could be very possible. Degradation of batteries is not a linear relationship. The Tesla people who have done this experiment showed the greatest lost of battery within the first 20,000 miles of being driven. After that, the battery degradation seems to slow down.

Only time will tell... It was also be variable amongst users. Some people may experience 30% loss after 3 years with minimal use. Some people may still have 90% battery after 300,000 miles driven. The Bolt has the newest generation of lithium ion batteries with an active cooling system. I didn't by a Leaf because of the high temps in my area and their passive cooling system. We need to compare the Bolt's battery degradation to the Volt and Tesla. The issues have been minimal with battery loss with those two examples, even with well over 100,000 miles driven in electric mode only. I use hilltop reserve because of the research that has been done with batteries, but we don't even know if GM gave us a buffer on the supposedly 60 kWh battery.

boltage
Posts: 383
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Re: "Full" battery levels dropping daily

Mon Nov 13, 2017 6:24 pm

discodanman45 wrote:We need to compare the Bolt's battery degradation to the Volt and Tesla. The issues have been minimal with battery loss with those two examples, even with well over 100,000 miles driven in electric mode only.


The Volt may not be a good comparison, since it has a very large buffer capacity.

Teslas have different battery chemistry. But also earlier ones had the free Supercharging, which may have been harder on the batteries than nightly home charging.

mwk
Posts: 11
Joined: Wed Oct 25, 2017 8:15 pm

Re: "Full" battery levels dropping daily

Tue Nov 14, 2017 6:55 pm

So I've been wondering this myself. I'm a new Bolt owner. I've had the car for three weeks now. During my first week, when the car would tell me it was "fully charged", I'd see an "estimated range" on the dashboard of around 220 miles. Now, three weeks later, when the car is "fully charged", the dashboard is telling me I have "estimated range" of 185 miles.

I live in Boston, and it has gotten colder these last two weeks, over what it was the first week I had the car. Would cold temperatures (30's at night, 40's during the day), affect this range to that extent? Or, is there a problem I need to get serviced? Right now, I've only ever charged the car using the 120V charge cord provided, plugging into a weatherproof outdoor outlet at my house.

I did check to be sure Hill Top Reserve is turned off, and it seems to be. I did set up a home location charging profile so I could charge at 12 amps instead of 8.

Is this all normal?

boltage
Posts: 383
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Re: "Full" battery levels dropping daily

Tue Nov 14, 2017 7:16 pm

mwk wrote:I live in Boston, and it has gotten colder these last two weeks, over what it was the first week I had the car. Would cold temperatures (30's at night, 40's during the day), affect this range to that extent?


When the weather gets cold, do you use the cabin heater? That has a significant effect on consumption and therefore estimated range.

mwk
Posts: 11
Joined: Wed Oct 25, 2017 8:15 pm

Re: "Full" battery levels dropping daily

Tue Nov 14, 2017 9:15 pm

boltage wrote:
mwk wrote:I live in Boston, and it has gotten colder these last two weeks, over what it was the first week I had the car. Would cold temperatures (30's at night, 40's during the day), affect this range to that extent?


When the weather gets cold, do you use the cabin heater? That has a significant effect on consumption and therefore estimated range.


I have used it, yes. But I've also tried turning it off entirely. It doesn't seem to make much difference.

GetOffYourGas
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Location: Syracuse, NY

Re: "Full" battery levels dropping daily

Tue Nov 14, 2017 9:24 pm

The Bolt uses a longer history than most EVs, in my experience. You may have to turn off the heater for a couple hundred miles to get that affect out of the range estimate.

mwk wrote:Would cold temperatures (30's at night, 40's during the day), affect this range to that extent? Or, is there a problem I need to get serviced?


To directly address this question, yes the cold could have an affect to this extent. It is highly unlikely anything is wrong with your car that needs to be serviced.
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV (traded for Bolt)
2015 C-Max Energi (302A package)
2017 Bolt Premier

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