Battery degradation data point

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sidehaas
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Post by sidehaas »

I just came across this short video which might provide a bit more confidence for anyone worried about battery deg after Battery Life did his test a couple of months back (I think BL eventually decided he had lost 7.5-8%).



The test isn't foolproof but considering the uncertainty range on his calcs it looks like his deg is no more than a maximum of 5%, and more likely 2-3%, after 1 year and 9000 miles. The amount of energy charged back in afterwards seems fairly consistent with the lower end of this range too, unless Gridserve chargers have a much higher loss than the Ionity ones tested by Battery Life here:
ID.3 Family Pro Performance (Jan 22), Makena Turquoise / East Derry alloys. Ohme Home Pro charger.

G43FAN

Post by G43FAN »

If you watch his later video at 14 months VW tested it and confirmed he'd lost 8%, so his calculations were pretty good. He also states 'worryingly' that VW said they expected an initial loss of maybe 5% in the first year but the degradation will slow in subsequent years.

For those that don't watch these videos and in a vain attempt to stop the astonished responses... 'Battery Life' (Chris) has by his own admission abused his ID.3 from a use and charging POV.
He did 22,000km in the first 12 months and 90% of that was DC charging. (Mostly on 100kW chargers) Plus he did frequent tests where he ran to 0% and then charged back to 100%.

sidehaas
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Post by sidehaas »

Yes, it seems likely the reason for the difference between the two cases is the charging usage pattern (and partly the higher mileage.) It's nice to have a second data point that indicates a much lower degradation for another car.
ID.3 Family Pro Performance (Jan 22), Makena Turquoise / East Derry alloys. Ohme Home Pro charger.
mawright89
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Post by mawright89 »

I saw that video too. As stated above he has thrashed his pack. You charge overnight twice a week at 7kw your not going to see 8 percent in a year. Nice to see the almost worst case scenario tho.
MotMot
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Post by MotMot »

Mine has dropped from 55950 Wh to 55300 in three months and 4500 miles (I have a couple of readings in between the first and last which follow this trend). Unfortunately I only have a first reading from early Nov - not from July when I bought it. FWIW I mostly charge between 20 and 80% (once to 100 - a couple of times to 90, lowest 11%) and have a 75/25 split of AC/DC charging - so I look after the battery fairly well.

So we can extrapolate and say its losing c. 2kwh of capacity a year at the present rate. 2/62x100 = 3.2% per year. Which is OK I guess. early days - more data needed etc..

All the battery deg curves I've seen have the steepest drop in the first few months/first year.
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Daveion
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Post by Daveion »

Are these tests scientific enough? If you conduct tests over the year does temperature not play a part in the result? I confess to not having studied it well but it seems logical given the sensitivity of the charging and discharge process to temperature.
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MotMot
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Post by MotMot »

It’s based on the OBD data. Doesn’t seem to be temp related. It’s steadily and slowly dropped.
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