80% charge

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kermit68
Posts: 396
Joined: Sat Sep 15, 2018 1:06 pm
Location: Rome / Italy

Re: 80% charge

Post by kermit68 » Mon Sep 07, 2020 8:27 am

hml wrote:
Mon Sep 07, 2020 7:50 am
Mine shows 100% when I charge it.
"Show" is the key word. What is being reported to the user as 100% is in reality 94% (more or less) of the maximum possible cell voltage. It's called "top buffer" and it's preventing the cells to reach a voltage level that could be dangerous for their health. So even charging at 100% is not stressing (at least not that much) the battery.
Then, if if don't need the full charge the day after, you can more safely stop at 80%, but just remember that 100% is not real 100% so the associated risks are close to zero.
MY20 Yulong White SE, 20", air suspension, privacy glass, black pack and other fine stuffs

denopa
Posts: 8
Joined: Sun Sep 06, 2020 6:57 pm
Location: London UK

Re: 80% charge

Post by denopa » Mon Sep 07, 2020 8:55 am

I've just finished my first charge, with Ubitricity, which shows the exact amount: 78.924 kWh. The interesting bit is that took me from 13% to 97% charge, which on a 90kWh battery should mean 75kWh (90 * [97%-13%]), and if we only access 94% of that because of the buffer, is really 71kWh. This means there's about 10% waste in the charging process, not an insignificant amount.

Wasabi Pea
Posts: 51
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Location: United Kingdom

Re: 80% charge

Post by Wasabi Pea » Mon Sep 07, 2020 9:18 am

denopa wrote:
Mon Sep 07, 2020 8:55 am
I've just finished my first charge, with Ubitricity, which shows the exact amount: 78.924 kWh. The interesting bit is that took me from 13% to 97% charge, which on a 90kWh battery should mean 75kWh (90 * [97%-13%]), and if we only access 94% of that because of the buffer, is really 71kWh. This means there's about 10% waste in the charging process, not an insignificant amount.
Yes, there will be some "waste": According to a technical document someone once shared on this forum, the HV battery has to be heated to 45°C whilst charging. Sometimes that is achieved just through the act of charging depending on ambient. After charging the HV battery has to be cooled to 26°C again to preserve battery life. Those two things will take some energy.

The waste % would presumably depend on the power (rate) of charge because the battery needs to be heated for longer. For example, I think I've also seen something that shows the granny charger has insufficient power to heat the batteries so that heating power comes from the battery itself, therefore making the granny charger the least efficient charging method.
At last I have my i Pace SE Firenze Red. Ordered 28th Feb, arrived 29th July. Broke 2nd August :cry: Back on the road again 7th August :D

SammyD
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Location: N.E Hampshire, UK

Re: 80% charge

Post by SammyD » Mon Sep 07, 2020 9:25 am

denopa wrote:
Mon Sep 07, 2020 8:55 am
I've just finished my first charge, with Ubitricity, which shows the exact amount: 78.924 kWh. The interesting bit is that took me from 13% to 97% charge, which on a 90kWh battery should mean 75kWh (90 * [97%-13%]), and if we only access 94% of that because of the buffer, is really 71kWh. This means there's about 10% waste in the charging process, not an insignificant amount.
The majority of people here have reported 80-84kWh capacity in their battery.
As to your case. I'd probably slow charge it to 100% (granny charger if possible) and let it sit plugged in for a few hours when at 100%. This will do some cell balancing. Mine was reporting 79-80 kWh capacity until I did this. now it reports 83.5kWh.

As has been said, don't leave it sitting at 100% charge for days on end. Go out for a drive (always a pleasure) and return home with it at 80-85% charge.
Driving "Hirundo Rustica" since 15th Mar 2019. Lovely Jubbly :D :D
S20B_20.27.3-568398 Maps : whatever is current.

Maxwell_400
Posts: 221
Joined: Mon Oct 14, 2019 10:09 am
Location: Norway

Re: 80% charge

Post by Maxwell_400 » Mon Sep 07, 2020 9:57 am

The battery capacity is not 90.00000000kWh. You have tolerances (+/-5%?) and temperature dependency.
I-Pace SE++, MY20, 18" summer & winter, no panoroof, towbar, spare wheel, H264, H280, TCU 18.2, BECM: BP-AAE-BC-AC-BE

Wasabi Pea
Posts: 51
Joined: Mon Jun 29, 2020 2:33 pm
Location: United Kingdom

Re: 80% charge

Post by Wasabi Pea » Mon Sep 07, 2020 10:23 am

SammyD wrote:
Mon Sep 07, 2020 9:25 am
I'd probably slow charge it to 100% (granny charger if possible) and let it sit plugged in for a few hours when at 100%. This will do some cell balancing. Mine was reporting 79-80 kWh capacity until I did this. now it reports 83.5kWh."
Interesting, thanks SammyD for some empirical data which always trumps opinion...I've seen several people refer to cell balancing, does anyone have anything official they can share on this?
At last I have my i Pace SE Firenze Red. Ordered 28th Feb, arrived 29th July. Broke 2nd August :cry: Back on the road again 7th August :D

Abu Dhabi Dude
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Location: United Kingdom

Re: 80% charge

Post by Abu Dhabi Dude » Mon Sep 07, 2020 2:51 pm

hml wrote:
Mon Sep 07, 2020 7:50 am
Mine shows 100% when I charge it. I charge over-night when the car is down to 20% - 30%. The frustrating thing is that it appears to only give me 230-240 miles on a full charge
Yes it shows 100%. But it’s 100% of what the car gives you access to. Not 100% of the whole battery capacity. The car display is calibrated to show the usable battery capacity as representing 0-100%, but there is an unusable amount of the battery above that.

CaptainJAG
Posts: 52
Joined: Mon Jun 22, 2020 7:55 pm
Location: Germany

Re: 80% charge

Post by CaptainJAG » Mon Sep 07, 2020 4:04 pm

Wasabi Pea wrote:
Mon Sep 07, 2020 9:18 am

Yes, there will be some "waste": According to a technical document someone once shared on this forum, the HV battery has to be heated to 45°C whilst charging. Sometimes that is achieved just through the act of charging depending on ambient. After charging the HV battery has to be cooled to 26°C again to preserve battery life. Those two things will take some energy.
There is no heating during charging. The battery will get warm by charging itself. As long as the battery is too cold, the Battery Management System will reduce charging to a minimum. Cooling starts at 35-38 degrees battery temperature during charging depending on charging speed and outside temperature.

BTW, that is the secret how JLR is limiting the charging speed at CCS Chargers... they have a software program in the cars system (it is not in the Battery Management System) which is „simulating“ cold outside temperatures and maybe some more parameters... the charging is reduced by this parameters (from 100kw to 80kw)
Every time, charging is reduced, the OAT drops to 0 degrees celsius... being at 28 degrees seconds before 😉

The latest BECS Software BP-AAF-BD-AD-BE runs the battery remarkably warmer as the software version before... maybe the first step into unlimited charging with 100kw or even more 😎

Fluff
Posts: 83
Joined: Thu May 21, 2020 9:26 pm
Location: UK

Re: 80% charge

Post by Fluff » Mon Sep 07, 2020 6:03 pm

CaptainJAG wrote:
Mon Sep 07, 2020 4:04 pm
Wasabi Pea wrote:
Mon Sep 07, 2020 9:18 am

Yes, there will be some "waste": According to a technical document someone once shared on this forum, the HV battery has to be heated to 45°C whilst charging. Sometimes that is achieved just through the act of charging depending on ambient. After charging the HV battery has to be cooled to 26°C again to preserve battery life. Those two things will take some energy.
There is no heating during charging. The battery will get warm by charging itself. As long as the battery is too cold, the Battery Management System will reduce charging to a minimum. Cooling starts at 35-38 degrees battery temperature during charging depending on charging speed and outside temperature.

BTW, that is the secret how JLR is limiting the charging speed at CCS Chargers... they have a software program in the cars system (it is not in the Battery Management System) which is „simulating“ cold outside temperatures and maybe some more parameters... the charging is reduced by this parameters (from 100kw to 80kw)
Every time, charging is reduced, the OAT drops to 0 degrees celsius... being at 28 degrees seconds before 😉

The latest BECS Software BP-AAF-BD-AD-BE runs the battery remarkably warmer as the software version before... maybe the first step into unlimited charging with 100kw or even more 😎
Sounds like the reverse of how you chip a diesel, the chip plays with the temperature reporting.
I-Pace SE 2019[Everything BLACK] Santorini,Pano, 20' BLACK,winter pack, adap cruise.

elbocko
Posts: 587
Joined: Sat Mar 09, 2019 3:49 pm
Location: Fareham, Hampshire

Re: 80% charge

Post by elbocko » Mon Sep 07, 2020 7:31 pm

hml wrote:
Mon Sep 07, 2020 7:50 am
Mine shows 100% when I charge it. I charge over-night when the car is down to 20% - 30%. The frustrating thing is that it appears to only give me 230-240 miles on a full charge
I would suspect that 240 miles ish is about normal unless you are Chewy or Jan.
El Bocko

E 2ERO, SE, Firenze Red, MY19, 18". Still loving it.
Infotainment - S20C_20.16.5-536345. It has gone backwards, now S20B_20.27.3-568398 @ 26/7/2020
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Battery Energy Control Shh, it won't say. H264v3 completed.

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