Quick question about battery charging

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Reuben80
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Post by Reuben80 »

Only time will tell who is doing it right. Which means we will never know because by that time owner would have been changed more than twice most probably.

DonJohnsonJr
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Post by DonJohnsonJr »

Reuben80 wrote: Fri Nov 18, 2022 6:50 pm Only time will tell who is doing it right. Which means we will never know because by that time owner would have been changed more than twice most probably.
True. So why be super careful careful now, if the time the battery would start showing degradation the value of the car is already substantially lower due to age anyway and not even owned by you?
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Reuben80
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Post by Reuben80 »

DonJohnsonJr wrote: Fri Nov 18, 2022 7:21 pm
Reuben80 wrote: Fri Nov 18, 2022 6:50 pm Only time will tell who is doing it right. Which means we will never know because by that time owner would have been changed more than twice most probably.
True. So why be super careful careful now, if the time the battery would start showing degradation the value of the car is already substantially lower due to age anyway and not even owned by you?
Because it does not cost me anything and because I have 8 years experience with a Toyota Yaris Hybrid with a 1kWh battery and the degradation was very sudden after the 7th year. When it degrades is too late. You cannot sell it and make money out of it.
asjo
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Post by asjo »

I have a Citroën C-zero from 2011 where the battery is doing quite okay and it has never been nursed within a narrow range of charge (I bought it from the local municipality, where they didn't care, and I have been charging it to full over night when charging since I bought it), so I guess your batteries may vary.
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hondaeboy
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Post by hondaeboy »

tomasblas wrote: Wed Nov 16, 2022 9:48 pm So if I charge it to 80% and use it for two days, then the battery will go down to 20% level before charging. I couldn't charge it when it's 30% level.
I didn't put this option c) as I assume it's worse than b) but also because I want to have some more battery left in case I need some extra miling.
I actually was wondering (and worrying) about this, too. Then I came across some underlying research from a while back by BMZ Gruppe, and the results kind of scared me. :o

https://pushevs.com/2018/04/27/battery- ... s-partial/

They looked at various charging models, ranging from cycling from 70% to 20% up to 100% to 0%. The former one giving a 12 (twelve!) times longer life. I actually was filling up my e upto 100% (at only 2kW), but the past few weeks came home a couple of times with only 1 km of charge left. Someone told me, I shouldn't do either of those things. Not fill it up to 100%... AND not deplete it to 0%. This research seems to confirm that.

If I translate the results to the values of the e, then the battery would reach its end-of-life (EOL) after "only" 100.000 km, if you consistenty cycle from 100% to 0%. And if you decide to only use 80% of the battery, it matters if you use the top or the bottom part of the battery! Going from 80% to 0% was 3 times better than always going from 100% to 20%.

100% to 0%: 500 cycles x 28,5 kWh = 14.250 kWh =~ 100.000 km til EOL
100% to 10%: 500 cycles x 28,5 kWh = 14.250 kWh =~ 100.000 km til EOL
100% to 20%: 1000 cycles x 28,5 kWh = 28.500 kWh =~ 200.000 km til EOL
90% to 0%: 1500 cycles x 28,5 kWh = 42.750 kWh =~ 300.000 km til EOL
90% to 10%: 1500 cycles x 28,5 kWh = 42.750 kWh =~ 300.000 km til EOL
90% to 20%: 2000 cycles x 28,5 kWh = 57.000 kWh =~ 400.000 km til EOL
80% to 0%: 3000 cycles x 28,5 kWh = 85.500 kWh =~ 600.000 km til EOL
80% to 10%: 3000 cycles x 28,5 kWh = 85.500 kWh =~ 600.000 km til EOL
80% to 20%: 3500 cycles x 28,5 kWh = 99.750 kWh =~ 700.000 km til EOL
70% to 0%: 5000 cycles x 28,5 kWh = 142.500 kWh =~ 1.000.000 km til EOL
70% to 10%: 5500 cycles x 28,5 kWh = 156.750 kWh =~ 1.100.000 km til EOL
70% to 20%: 6000 cycles x 28,5 kWh = 171.000 kWh =~ 1.200.000 km til EOL

However, it would be difficult to ruin the battery beyond the warranty limit of 8 years / 160.000 km. Most people will usually charge above 20%, which would leave the battery good enough for at least some 200.000 km. And considering the average driver only drives 12.000 km per year, even maximally degrading the battery by cycling from full to empty all the time, the battery would still be barely better than "end-of-life" after 8 years.

Still, I had no idea the various ways of cycling had such a significant impact. I do know that it made decide to use the 80% charge limit on the car AND keep using the trickle charger as much as possible. :lol:
2021 Honda e Advance on 16" RC30 wheels with Goodyear 195/55 & 205/55 tyres.
Wrapped in Red metallic with full black and cinnamon leather interior.
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londiniumperson
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Post by londiniumperson »

Interesting, however reading that article, the batteries under test were charged to an actual 100% and depleted to an actual 0%, whereas as the article states:
Electric cars already have BMS (Battery Management Systems) that prevent batteries from being fully charged or discharged, however BMS aren’t created equal, some are more protective than others.
Most electric cars have BMS that allow them to use roughly 90 % of their total battery capacity (from 95 to 5 %)


It is well known that the Honda e has a battery size of 35kWh with 28.5kWh usable (i.e. 80% and assuming 10% each off top & bottom), therefore if we charge to 100% & discharge to 0% of the usable battery, then using the chart which you posted:
90% to 10%: 1500 cycles =~ 300.000 km til EOL
then we would still be good for 300,000km and anyone nursing the battery will get way more.
2022 Advance in Crystal Black Pearl on 17's - 08/2020-Current
2015 VW Tiguan (Pure White) - 04/2018-Current
1991 Honda Beat PP1 (Festival Red) - 11/2022-Current
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hondaeboy
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Post by hondaeboy »

londiniumperson wrote: Sun Feb 12, 2023 11:16 pm It is well known that the Honda e has a battery size of 35kWh with 28.5kWh usable (i.e. 80% and assuming 10% each off top & bottom), therefore if we charge to 100% & discharge to 0% of the usable battery, then using the chart which you posted: then we would still be good for 300,000km and anyone nursing the battery will get way more.
Ow! That's a good point. And good news.

So cycling between 80% and 15% would be very close to an actual 70% to 20%. And for the battery life calculation we must use the actual battery capacity in stead of the usable part, leaving us us with 1,5 million km's until EOF! Noice!

Not that the car will last 1,5 million km's, but at least the battery degradation during the few hundred thousand km's that it's in operation will be pretty minimal, if you cycle this carefully.
2021 Honda e Advance on 16" RC30 wheels with Goodyear 195/55 & 205/55 tyres.
Wrapped in Red metallic with full black and cinnamon leather interior.
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londiniumperson
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Post by londiniumperson »

This is assuming that I have understood that article correctly.
2022 Advance in Crystal Black Pearl on 17's - 08/2020-Current
2015 VW Tiguan (Pure White) - 04/2018-Current
1991 Honda Beat PP1 (Festival Red) - 11/2022-Current
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