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 Post subject: Re: Estimating Battery Degradation
PostPosted: Fri Oct 13, 2017 2:38 pm 
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Verkehr wrote:
The e-golf has a diagnostic parameter called "expanded battery limits" (warning: speculation follows) which may open up more battery as it ages to retain range. So then the pack could degrade even more than 30% net capacity and still deliver >70% of its rated range for warranty purposes.


Duly noted. Though that would involve a higher state of recharge, above the initial 88% useable, thereby shortening the battery life even quicker.

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Fri Oct 13, 2017 3:51 pm 
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Joined: Fri Mar 27, 2015 4:13 pm
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Location: Los Altos, CA
JoulesThief wrote:
Verkehr wrote:
The e-golf has a diagnostic parameter called "expanded battery limits" (warning: speculation follows) which may open up more battery as it ages to retain range. So then the pack could degrade even more than 30% net capacity and still deliver >70% of its rated range for warranty purposes.


Duly noted. Though that would involve a higher state of recharge, above the initial 88% useable, thereby shortening the battery life even quicker.

Now that I have my tinfoil hat firmly on my head, I will say the following:

Shortening the total battery life doesn't matter to VW as long as it gets the battery past the capacity warranty time and mileage limit.

This is very much like refusing to address oil consumption in a gas engine until it's to the point that it will destroy the catalytic converters within the emissions warranty.

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Fri Oct 13, 2017 7:05 pm 
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Sure, I understand that VW doesn't want to provide a new battery to e-Golf owners. The question remains: where is this "expanded battery limits" parameter found? How does Verekhr know of its existence? Or is this just a joke that certainly seems credible thanks to VW's expertise in cheating thanks to the TDI criminal algorithms that are part of VW's company culture?

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Sat Oct 14, 2017 2:04 pm 
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Joined: Sat Dec 19, 2015 4:16 pm
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f1geek wrote:
Sure, I understand that VW doesn't want to provide a new battery to e-Golf owners. The question remains: where is this "expanded battery limits" parameter found? How does Verekhr know of its existence? Or is this just a joke that certainly seems credible thanks to VW's expertise in cheating thanks to the TDI criminal algorithms that are part of VW's company culture?

Screenshots from OBDeleven below

https://imgur.com/a/zhtOT
ImageImage
ImageImage

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Sat Oct 14, 2017 2:10 pm 
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What's more, here is an article on Battery University that details changing battery limits in EVs. No tin foil hat necessary.

http://batteryuniversity.com/learn/arti ... vehicle_ev

Quote:
EV makers must further account for capacity fade in a clever and non-alarming way to the motorist. This is solved by oversizing the battery and only showing the driving range. A new battery is typically charged to 80 percent and discharged to 30 percent. As the battery fades, the bandwidth may expand to keep the same driving range. Once the full capacity range is needed, the entire cycle is applied. This will cause stress to the aging battery and shorten the driving ranges visibly. Figure 4 illustrates three SoH ranges of an EV fuel gauge.
Image

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Last edited by Verkehr on Sat Oct 14, 2017 7:30 pm, edited 1 time in total.

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Sat Oct 14, 2017 2:32 pm 
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OBDeleven or PRO model that you bought? Great find Verkehr!

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Sun Oct 15, 2017 8:30 am 
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Joined: Sat Dec 19, 2015 4:16 pm
Posts: 115
I am using obdeleven pro

Regarding hidden degradation, the e-golf batteries tested here, for example:

https://avt.inl.gov/vehicle-button/2015 ... gen-e-golf

Battery #1 lost 9.8% over 12k miles
Battery #2 lost 6.8% "
Battery #3 lost 7.5% "
Battery #4 lost 9% "

Has anyone here observed decreases in range? I certainly haven't at 13k miles, but I'm "babying" the battery.

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Sun Oct 15, 2017 9:20 am 
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Verkehr wrote:
I am using obdeleven pro

Regarding hidden degradation, the e-golf batteries tested here, for example:

https://avt.inl.gov/vehicle-button/2015 ... gen-e-golf

Battery #1 lost 9.8% over 12k miles
Battery #2 lost 6.8% "
Battery #3 lost 7.5% "
Battery #4 lost 9% "

Has anyone here observed decreases in range? I certainly haven't at 13k miles, but I'm "babying" the battery.


Define "babying" or what procedures you follow to give good care to your battery?

I lost some capacity at the end of summer 2016 on mine. My fully recharged range dropped from 129 miles to 119 to 121. Summer of 2017, the highest range I ever saw showing was 123 miles of range, that was on a recharge that netted an average of 6.3 miles per kwh. Now that it's getting cooler again with fall here in Southern California, I suspect my estimated range will decrease some more with the cooler weather. At that rate, over 2 years, as of Oct 6th, 2017, I've lost about 7% capacity in 13200 miles. 121/129 miles on the Guess O Meter.

I am OK with recharging at a 7.2 Kwh recharge rate, and I think the ChargePoint DC 100 chargers with about a slightly slower 1C charge rate are OK, but the 55KWH DC200 chargers that fill up to 80% in 20 minutes are probably really hard on the battery and it's capacity being diminished. No Li Ion batteries that I know of can stand a recharge rate that fast and not suffer from loss of capacity. It's just too brutal on the battery chemistry, and damaging.

It's also my belief, though I can not prove it, that using advanced "B" mode for driving with it's powerful regenerative braking, and current producing capabilities, is also at a damaging recharging rate also, to the batteries. I don't use "B" mode at all any more, I use D1, and try to keep the regenerative braking capacity below the level of 2 out of 3, on the dash meter.

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 Post subject: Re: Estimating Battery Degradation
PostPosted: Sun Oct 15, 2017 9:34 am 
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f1geek wrote:
Sure, I understand that VW doesn't want to provide a new battery to e-Golf owners. The question remains: where is this "expanded battery limits" parameter found? How does Verekhr know of its existence? Or is this just a joke that certainly seems credible thanks to VW's expertise in cheating thanks to the TDI criminal algorithms that are part of VW's company culture?


Sure, they want to provide a new battery to e-Golf owners, just that they want it on your dime, not on their's. VW needs to sell some parts on these cars, to keep the dealerships in business and making a profit. They don't make much on new cars, they make their money on Service. Service is their major profit center, and Parts. You can bet they want to sell you a new battery.

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2014 Touareg TDI LUX

Full spectrum VW owner, life is too short to wait to drive for a recharge.


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 Post subject: Re: Estimating Battery Degradation
PostPosted: Wed Nov 15, 2017 9:12 pm 
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Joined: Fri Jan 23, 2015 1:18 pm
Posts: 457
2015 SEL Battery Degradation update:

959 days of driving, 22,400 miles. After a full charge I drove 101 miles and had 2 miles of range left (2%), averaging 5.6 mile/kWh. Theoretical usable capacity is 101/5.6/(1-0.02)=18.4 kWh. Assuming the original usable capacity was 21.6 kWh, that's a 15% loss. Assuming a linear rate of drop, that means I'll hit 70% in another ~3 years.

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