Charging 80 or 100%

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Why? Because it was 2014 and BMW was new at this coming off of the Active-e experiment and didn't know how to market EVs to the masses, and felt the KISS principle was the right way to go with respect to charging and not alternating their customers.

That would be my guess. They've certainly charged their tune with their current EVs.

As noted earlier in this thread, when 100% is indicated, the battery is at around 95% actual.

Nobody needs to "miss out" on mileage.I keep my charge around 80 and when I need full range I charge to 100.
I actually know the answer to this because it's quite the controversial subject in places like Facebook. Since 2021 (2022 models in the UK) had the new i4 i5 and i7 rolling out, they modified that " I Series " book to be more generic knowing the i3 was done for, the other models have completely different chem and BMS :( ....but yea the handful of owners with i3s got a "rogue manual" ...kinda funny.
I agree 100% with the 100%. JTylee is 100% correct too. The manual was changed in February 22 to contain the ‘generic’ newer i series advice. The critical thing is that the i3 does passive top end cell balancing when charge is complete and we have no stop percentage. I.e. charge it to ‘full’.

Conversely the newer models have a ’stop’ at 80% as the default in the same way that Tesla does with its active cell balancing as it charges. (I have no knowledge of the BMW cell balancing technique in the i4).

The newer manual therefore is unfortunately going to completely unbalance the pack if people follow that advice.

This is what happened to my original 60Ah when I only charged (on free vend) during retail visits and never past 80%. Big mistake took months to recover by leaving it plugged in (coincidentally when free charging ceased). 35 miles at 100%. Eventually went back up to 70 miles.


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Now excessive rapid charging WILL degrade the battery if used too much.
I have some Tesla charts that claim to show, from users, that those who only ever used supercharging had lower capacity loss over time. Data was collected by a Belgian user groups so has been somewhat challenged but I don’t see as we have an excellent heat management system (better than Tesla?) and a very slow charge curve after 85% (ok different for all three models) why rapid charges would be an issue? It’s the heat at 100% for a single cell and we don’t ever get to 100% anyway (unlike Tesla) and keep cool?

The outliers at the top were apparently supercharger only but I guess self reporting is a little unreliable.


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The mi3 app reports that at an indicated 100% charge level, the actual charge level of our 2019 BEV is 96.1% which is much higher than 80%. Like eNate, I don't want to leave our battery pack at a high charge level any longer than necessary. Periodically, when I know that I will be driving soon, I charge to 100% to help the BMS calibrate its charge level calculation. For the same reason, I also discharge to 0% occasionally. I usually record what mi3 reports both at 0% and 100% to check how well cell charge level balancing is working (it seems to work very well) and to determine whether any cells are weak (none so far).

However, if managing the charge level is more than you would like to do, your battery pack will probably be fine always charging to 100%. Without a large sample, it's difficult to know whether this makes any difference over the long run.
Which brand of OBD 2 reader do you use with the mi3 app ?
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I have a 2017 I3 94ah in Australia. We have recently lost remote visibility of the car's state if charge due to 3G cellular network shutdown.

Would the Vgate Icar2 wifi adaptor above allow me to connect to our home wifi in the driveway and provide remote charge state visibility... At least while chatting at home? Are there other options?
Would the Vgate Icar2 wifi adaptor above allow me to connect to our home wifi in the driveway and provide remote charge state visibility... At least while chatting at home? Are there other options?
The Vgate iCar 2 WiFi adapter is a simple WiFi base station in that one's smartphone could connect to it so that the mi3 (iOS) or electrified (Android) app could display the current charge level. I doubt that it has sufficient power to be able to connect to it from within one's home, but I've never tested its range.

I don't know how the WiFi base station that provides WiFi access in your driveway would be able to connect to a Vgate iCar 2 WiFi adapter.

U.S. i3's sound the burglar alarm when an OBD adapter remains plugged in for some period of time (not sure how long) after an i3 is shut down. This can be turned off via coding, but it would make an i3 slightly less secure if someone could plug in an OBD adapter without the driver knowing.
Many thanks for your advice... I'll have a good look at the Vgate Icar2 specs... I'll think about the "security" issue..
It isn't an ideal solution, but unless there is a better way, maybe it is "a solution".
I bought the

Veepeak OBDCheck BLE Bluetooth OBD II​

from Amazon Uk last week. It works fine with IoS and Android devices.

Re main thread topic (80 or 100)

My experience is using partial charges is fine as long as VERY occasionally go near 0% and 100%
Due to the inability to end charging at a lower percentage and charging mostly overnight, I have always charged to 100%, but hardly ever let the car sit for more than a few days on a full charge. On the other hand, I seldom discharge below 20%. When DC-fast charging, I stop at 80-85% unless I really needed more juice. I think that restricting DC-charging to a minimum is a good idea for older battery chemistries, like other have stated. As regen braking is also a form of DC-fast charging, my theory is that if you are gentle on the regen, the battery will last longer in the end. I cannot scientifically proof it though, just my instinct.

Up to now my slowly deminishing range is in line with "normal" degradation at 70.000 miles (but definitely higher than f.e. newer Tesla cars that run 200.000 miles and have an average degradation of 15%, thanks to their much bigger battery), but still 70 miles or even more left. I never drive it to empty, maybe I should do that and then fully recharge to re-adjust the SoH algorithm and to temporarily up the range, but I guess after a while everything will be back to "normal", so maybe it is pointless. Maybe someone can shine a light on this?
I use an OBDLink LX.
I've not charged my car over about 83% for a few months, using a smart charger. It's set to 80% but does run over sometimes, so maybe it's not as smart as it should be :) . I don't cover many miles so that's probably 5 or so charges as I generally run it down to between 30% and 40%, usually closer to 30%, before charging. According to the Electrified app the cells are perfectly balanced.

ABC/charging to 100% just depends on use case I think. If using a significant amount of range per day(40%+) then sure it make sense to charge it to 100% overnight. If like me doing short local trips and not using the car daily then it doesn't.

I think the debate will go on for decades about charging best practices
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Slightly off topic...

We have a 2017 BMW I3 Rex 94AH in Australia.

Sometimes the main display includes a numerical battery percentage state of charge. Other times it only had a bar graph and range estimate. We haven't figured out what causes this change nor huw to change between different display options. The settings menu doesn't seem to control these options.

Can anyone tell us how to select a preferred display option?

I'm sure others have mentioned this by now, but here goes since you're LHD like us Brits (or poms😉).
I have same 94ahr rex 2017 model as yours, so left hand stalk has a button in the tip that cycles between;- odometer, combined miles left (inc' rex), percentage battery charge, current average efficiency in miles/kwhr, instant as you drive miles/kwhr efficiency, average speed, temperature, time, blank, back to odometer.

Just cycle through to display you prefer and leave it there. It should keep that even through on/off usage periods.
Excellent. Many thanks. I even resorted to reading the manual but didn't find the answer until your very helpful reply here.😀
On my US model at least, that button is labeled "BC" and I've never found an explanation for that that didn't involve Lucasian amounts of handwaving and Midichlorians. It's possibly "Be Confused," since you can touch it unknowingly and wonder later why your display changed.

The manual isn't particularly well suited to discovering functions you don't already know about, IMO . . . so it's good this forum exists to employ natural intelligence in cases like this.