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Discussion Starter #1
Reading this post by @yoh-there here, I got to thinking that I have never found any definitive information with regard to charging lithium-based batteries.

Are many small charges worse than one large charge? Which is more detrimental to battery life - the total amount of charges, or the total time spent charging? Or something else?

Any chemists out there?
 

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Discussion Starter #3
I'm sure it's little and often, though with a Renault battery lease is battery life a consideration?
Good point! This is perhaps more a question on behalf of the "i" owners out there. :)

Though it raises another question in my mind; what sort of range does a 75% capacity battery get you?
 

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Generally speaking lithium based batteries dislike: -

Being over discharged.
Being over charged.
Sitting for long periods of time at a high SOC.

They're pretty indifferent to number of charging cycles, think about a car's regen, that recharges the car for a few seconds at a time, many times per hour. Fast charging seems to make little difference, even showing reversing degradation at times.

Keeping them in the 20-80% area has been touted by many as the 'best'.
 

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Wastes a lot of energy carrying a full load of electrons if you don't need 'em.....

Edit: i was being flippant then realised you get no regen when charge is high so maybe best to charge less often ??
Reading this post by @yoh-there here, I got to thinking that I have never found any definitive information with regard to charging lithium-based batteries.

Are many small charges worse than one large charge? Which is more detrimental to battery life - the total amount of charges, or the total time spent charging? Or something else?

Any chemists out there?
 

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Zoe Devotee
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Good point! This is perhaps more a question on behalf of the "i" owners out there. :)

Though it raises another question in my mind; what sort of range does a 75% capacity battery get you?
I learned from a CISCO course that the correct answer to this question is.... "..it depends!"

Yes! So 60 miles if you consider 80 miles to be a rough guide to the ZOE range.
However its not quite as clear as that... i'm down to 92% user available but car still shows 21.6kwh available on a 100% charge, based on 22kw user available that kwh remaining is closer to 98% of original capacity available.

If a 75% pack was genuine that would leave you with 16.5kwh so range from 3.5mpkwh to 4.5mpkwh in my case would say 57miles to 74miles. Still ok to be honest! I cover 6miles each way for commute. I could still do all week pretty much. I could still do Aviemore in Summer with 1 stop.
 

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Unfortunately the car can't be told to stop at a SOC but if you're on lease then although you might feel conscientious about shortening the battery life it's not world ending.

Another thing I found is the GOM is greatly impacted by not having the regeneration. For example I routinely get 4.5+mkW daily but because of a commute period in early spring/summer I was getting 3.2-3.4 so now I'll get told 75 miles even though I just did a 75 mile leg and still havd some left before saving the trip.

I've been told that LIon likes 50-80% best and has a best compromise cycle tolerance by battery techs talking about mobile device batteries, car batteries are the same chemistry.

So if there is anything to be learned it's set your charge calendar so it only puts in so much each evening that you never go above 80-90% even on the weekends if you want to preserve your battery best.
 

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Zoe Devotee
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Zoe has a true capacity of 26kwh but only allows you to use 22kwh. This is around 84.5%. Presuming there is a bit of top of that it seeks it's unlikely to charge a Zoe battery to 100% true.
 

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I plug the car in every single day without fail (it's just part of the routine of parking it and then closing the garage door) and it charges overnight from E7.

If I owned the battery I would be concerned about always filling it to 100% (and especially when we go on holiday when it would sit at 100% for a fortnight). But since I don't, I'm not.
 

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I think the point Sandy was making was that you could never charge to 100% even if you wanted to. So no need to worry at all even if you have an 'i'
 

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Presuming there is a bit of top of that it seeks it's unlikely to charge a Zoe battery to 100% true.
Right, but that is a presumption.

The Model S 85 for example has 77kWh of usable capacity but the hidden capacity is all at the bottom - 100% really is 100%.

And the Zoe does pack balancing at 100% charge which strongly suggests to me that it really is filling them right up to the cell manufacturer's 100% voltage point in order to do so.
 

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Discussion Starter #14
Right, but that is a presumption.

The Model S 85 for example has 77kWh of usable capacity but the hidden capacity is all at the bottom - 100% really is 100%.

And the Zoe does pack balancing at 100% charge which strongly suggests to me that it really is filling them right up to the cell manufacturer's 100% voltage point in order to do so.
This presentation explains it all (I've linked to the point where he talks about charging and capacity):
 

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This presentation explains it all
Well, not really.

All that presentation says is that they under-declare capacity, and that the car's systems then make sure that the lesser of the declared and real capacity is made available, with the effect that the battery's degradation is reduced and users experience a relatively flat degradation curve over a long period of ownership.

But it doesn't say whether or not they do this by leaving headroom at the top of the charge cycle, or the bottom, or both (and all of thse would have the effect of lengthening pack life).
 

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Zoe Devotee
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17,000 Zoes sampled... there isn't 17k R240s on the road now is there? There certainly wasn't in 2015. Also the 23.3kwh may be true capacity for use but customer usable is restricted, it's said in the video.

No Zoes display more than 22.5kwh usable. Why does this bloody video keep getting dredged up and then quoted as fact, but no one watches it or listens.
 

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17,000 Zoes sampled... there isn't 17k R240s on the road now is there? There certainly wasn't in 2015. Also the 23.3kwh may be true capacity for use but customer usable is restricted, it's said in the video.
The 50,000th Zoe came off the production line in April this year.

The packs are identical between Q210 and R240, aren't they? It's the motor and charger that are different.
 

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Zoe Devotee
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Yup, 50k Zoes, my guess is its still Q210 biased in pure sales volume.

Same pack in all cars.

How could the stats for R240 from 2015 show a sample of 17k cars measured? Answer, it's can't those are Q210 figures.
 

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Yup, 50k Zoes, my guess is its still Q210 biased in pure sales volume.

Same pack in all cars.

How could the stats for R240 from 2015 show a sample of 17k cars measured? Answer, it's can't those are Q210 figures.
OK I'm confused. Who said that this was a sample of R240s? Or even mentioned the two motor variants at all in this thread?
 

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Discussion Starter #20
OK I'm confused. Who said that this was a sample of R240s? Or even mentioned the two motor variants at all in this thread?
^ This!

I've watched the video twice. I don't recall him mentioning that the collected battery data was R240-specific.

@mgboyes my initial interpretation of his chart was that it was the top end that was "spare", but actually, you're right; he doesn't specify which end(s) the spare capacity occupy.
 
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