Jaguar I-Pace Forum banner

80% charge

12K views 42 replies 19 participants last post by  dernotte 
#1 ·
Hi all,

First post here, just picked up our 2019 First Edition on Friday, already having a lot of fun with it! I used to have a convertible XK before we had kids, it's been BMWs since then, what was I thinking :lol:

I see a lot of reference to 80% as a charge level not to exceed, for example in the pinned topics (super useful), but where does that number come from? What happens if I charge to 100% once every couple of weeks and use that bit by bit for my commute ?

I tried searching but the tool doesn't accept "80%" as a search term (too short), so I apologise for asking for info which most likely already exists.
 
#2 ·
I've been away this week, I have charged to 100% 6 times in 7 days, I wouldn't worry about how many times you charge to 100% JLR certainly have said its no problem for the batteries. In fact what is far worse is leaving it for long periods at a very low SOC.

Just charge how and when you see fit and enjoy the car, don't fret about stuff like this.
 
#3 ·
Charging to full every couple of weeks should be no problem whatever. 1000 cycles would take forty years of that, and I think 1000 full charge cycles is well within the capabilities of the Jaguar batteries. I think the only real no-no is to leave the car on charge for weeks, or god-forbid months. JLR advise long term storage at below 60%. Personally I like to leave mine at 80% or less (but above 40%) if I am not going to drive it for a couple of weeks, but that is only because I am trying to give the battery the very best chance of maximum longevity, and my caution is probably unnecessary.
 
#4 ·
There is nothing wrong with charging to 100% on a regular basis. However: If you do fast DC charge on a longer trip (> 50kW), it is good practise to charge to 80% only, as the last 20% would add extra stress to the battery. The charge rate will also drop dramatically beyond 80% SoC, so you would be wasting you time either.
 
#5 ·
I suppose it also depends on how long you intend to keep the car and whether or not it's leased...

As EV's start to hit the used car market in greater numbers will it be possible for people to check the recharge trends of the battery? Or even just a battery healthcheck? Such a thing could wipe £5-10k off a cars value in extreme circumstances I guess.

On the other hand if like me, and my business partner, your cars are leased... It's sort of a non-issue isn't it? On a lease car the battery just needs to survive 2-3 years without losing too much capacity to remain a useful car. As has always been the way with lease cars - look after the bodywork but don't worry too much about looking after the power plant because you're never going to have to live with it and it will always be under warranty.

If you're looking to re-sell one day, or simply want the car to last for a good while, probably best to follow Jag's 'ideal' charging regime as much as possible. They aren't giving the advice for the sake of it.
 
#7 ·
denopa said:
Thank you for the useful and fast answers, may I ask where I can find JLR's guidance ? iGUIDE doesn't seem to have anything there.

Is there also a way to keep up to date on incoming software releases and features ?
You cant find the guidance because Jaguar don't give any. Basically, Jaguar themselves say this is a non-issue. They recommend getting home every night and plugging in back to 100%. However, many people (myself included) play it cautiously and stick to generally accepted good practice for Lithium batteries, which is to avoid charging to full unless you need to for a long trip. However, many people do not bother and so far there has not been a huge number of people complaining about degradation. Personally, I'll stick to charging to 80 unless I'm planning a long trip the next day. But I am possibly being overcautious.

The other reason you will see a lot of talk about 80% is that the car will charge at a good speed up to 80% on rapid chargers (CCS). Above 80% the charging speed slows, so most people will charge to 80% and then move on as it reduces the overall journey time.

With respect to the comments about it not mattering for a lease vehicle though, I'd just like to add that if carbon footprints matter to you, then it is worth looking after the battery regardless as the better you look after it whilst in your care, the longer it will last and therefore will reduce the carbon footprint associated with the vehicle's lifetime.
 
#8 ·
Abu Dhabi Dude said:
denopa said:
Thank you for the useful and fast answers, may I ask where I can find JLR's guidance ? iGUIDE doesn't seem to have anything there.

Is there also a way to keep up to date on incoming software releases and features ?
You cant find the guidance because Jaguar don't give any. Basically, Jaguar themselves say this is a non-issue. They recommend getting home every night and plugging in back to 100%. However, many people (myself included) play it cautiously and stick to generally accepted good practice for Lithium batteries, which is to avoid charging to full unless you need to for a long trip. However, many people do not bother and so far there has not been a huge number of people complaining about degradation. Personally, I'll stick to charging to 80 unless I'm planning a long trip the next day. But I am possibly being overcautious.

The other reason you will see a lot of talk about 80% is that the car will charge at a good speed up to 80% on rapid chargers (CCS). Above 80% the charging speed slows, so most people will charge to 80% and then move on as it reduces the overall journey time.

With respect to the comments about it not mattering for a lease vehicle though, I'd just like to add that if carbon footprints matter to you, then it is worth looking after the battery regardless as the better you look after it whilst in your care, the longer it will last and therefore will reduce the carbon footprint associated with the vehicle's lifetime.
The weird thing is that far cheaper devices (from tablets, to phones and laptops) have software that actively manages charge to avoid hitting 100%. My fairly new Lenovo Android tablet seems to be designed to limit charge to 60% in most scenarios (which works pretty well given the run time I get from that). You would expect the car to manage this too at least periodically to avoid fully charging every cycle rather than relying on manual intervention.
 
#9 ·
electric beagle said:
The weird thing is that far cheaper devices (from tablets, to phones and laptops) have software that actively manages charge to avoid hitting 100%. My fairly new Lenovo Android tablet seems to be designed to limit charge to 60% in most scenarios (which works pretty well given the run time I get from that). You would expect the car to manage this too at least periodically to avoid fully charging every cycle rather than relying on manual intervention.
The car effectively does this by having a top buffer on the battery. You can never actually charge it to 100%. The best you can do is charge it to about 94% of its total capacity, so you are never taking it to its actual full capacity. Also, the active thermal battery management provides a lot of protection. However, that is only active while charging and driving so has no benefits when leaving the car parked for long periods while fully charged.
 
#11 ·
hml said:
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.
 
#12 ·
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.
 
#13 ·
denopa said:
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.
 
#14 ·
denopa said:
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.
 
#16 ·
SammyD said:
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?
 
#17 ·
hml said:
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.
 
#18 ·
Wasabi Pea said:
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 😎
 
#19 ·
CaptainJAG said:
Wasabi Pea said:
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.
 
#20 ·
hml said:
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.
 
#21 ·
Wasabi Pea said:
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?
Yes sir. If you want to balance the battery the "best" way, the official way is to drive the car as low as possible. Somewhere between 0-10% would be good.
Then have the car unlocked and turn on the hazard blinker. Start charging the car with a granny charger, let the car charge up until it stops charging with the car unlocked and the hazard lights on. Caution: This will take a long time, so you should do this in a locked garage.

I did this, and gained about 7kWh.
 
#22 ·
ELray said:
Yes sir. If you want to balance the battery the "best" way, the official way is to drive the car as low as possible. Somewhere between 0-10% would be good.
Then have the car unlocked and turn on the hazard blinker. Start charging the car with a granny charger, let the car charge up until it stops charging with the car unlocked and the hazard lights on. Caution: This will take a long time, so you should do this in a locked garage.

I did this, and gained about 7kWh.
Seriuosly ? :shock:
 
#23 ·
kermit68 said:
ELray said:
Yes sir. If you want to balance the battery the "best" way, the official way is to drive the car as low as possible. Somewhere between 0-10% would be good.
Then have the car unlocked and turn on the hazard blinker. Start charging the car with a granny charger, let the car charge up until it stops charging with the car unlocked and the hazard lights on. Caution: This will take a long time, so you should do this in a locked garage.

I did this, and gained about 7kWh.
Seriuosly ? :shock:
I am a bit unsure about the 7kWh figure. But thats what I could read from the ODBII port with the app Power Cruise Control.
I went from 340km range to 420km. It's now about 410km at fully charged.
 
#24 ·
To my knowledge (but I could be wrong as I'm not a JLR engineer), cell balacing is perfomed every time you leave the car charging up to 100% and leave the charger connected after reaching 100%. Also, I never performed the procedure as you described but wattcat is reporting for my car 87 kwh ath the end of each charging. After a year and a half I cannot immagine I can have such energy in the battery without having performed a single cell balancing.

Interesting, last week I had some free time and I charged up to 100% at a DC 50kw charger. After reaching 100% with the battery temperature at 31°C, the car paused the charge and started to cool he battery down to 28°C. After reached that temperature the charging has been resumed at a very slow speed (0,8kw according to wattcat) for more than 20 minutes. The total kwh increased from 86.4 to 87.1. That sounds as cell balancing to me.
 
#25 ·
kermit68 said:
To my knowledge (but I could be wrong as I'm not a JLR engineer), cell balacing is perfomed every time you leave the car charging up to 100% and leave the charger connected after reaching 100%.
I do not think that is accurate, the car disconnects the charger when it reaches 100%. If I start climate it will reconnect again.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top