Battery loosing charge?

[Trykpaa]

However, the video talks about (thankfully there are English subtitles) the Chinese made Model 3's which have lithium iron phosphate batteries - a different type of battery to the Honda e's batteries. It says they have a very flat voltage curve during charging and discharging which makes it difficult to determine the state of charge (the voltage rises near fully charged, which makes it easier for the BMS to determine the SOC, hence the recommendation to charge to 100% farily frequently). Also charging to 100% doesn't degrade lithium iron phosphate batteries as quickly as it does for more conventional lithium ion batteries.

Different chemistry, same principle though. And Honda also recommends charging to 100% despite it ought to cause more degradation.

[londiniumperson]

However, the video talks about (thankfully there are English subtitles) the Chinese made Model 3's which have lithium iron phosphate batteries - a different type of battery to the Honda e's batteries. It says they have a very flat voltage curve during charging and discharging which makes it difficult to determine the state of charge (the voltage rises near fully charged, which makes it easier for the BMS to determine the SOC, hence the recommendation to charge to 100% farily frequently). Also charging to 100% doesn't degrade lithium iron phosphate batteries as quickly as it does for more conventional lithium ion batteries.

Different chemistry, same principle though. And Honda also recommends charging to 100% despite it ought to cause more degradation.

Charging to 100% on the 3kW granny or 7kW home charger seems to be recommended every now and then to ensure that the cells are equally charged (aka balanced) for all EVs. See the MG EV Facebook group, forums etc and you'll see that's currently a hot topic.
We as Honda e owners currently have no way to check the battery voltage at 100% charge unlike most other EVs. The MGs appears to be impacted more than most in this area due to numerous BMS (battery management system) updates since launch.

[Number5]

Charging the E to 100% should not be an issue. Having 28kW ish available from 35.3kW suggests actual SOC can only operate between 10-90%. Cars % readout is calibrated 0-100% over 80% of actual battery.

[iHansz]

Charging the E to 100% should not be an issue. Having 28kW ish available from 35.3kW suggests actual SOC can only operate between 10-90%. Cars % readout is calibrated 0-100% over 80% of actual battery.

That is exactly what I thought and think. But because many here indicate that they normally do not exceed 80%, I do that too.

[keithr]

Charging the E to 100% should not be an issue. Having 28kW ish available from 35.3kW suggests actual SOC can only operate between 10-90%. Cars % readout is calibrated 0-100% over 80% of actual battery.

There's actually about 31.2kWh available (88% of 35.5kWh), at least when the car is driven around town. It drops to about 28.5kWh when the car is driven at faster out of town speeds, which is due to exponentially more energy being wasted as heat within the battery at higher current draw.

[Haaploos]

Charging the E to 100% should not be an issue. Having 28kW ish available from 35.3kW suggests actual SOC can only operate between 10-90%. Cars % readout is calibrated 0-100% over 80% of actual battery.

There's actually about 31.2kWh available (88% of 35.5kWh), at least when the car is driven around town. It drops to about 28.5kWh when the car is driven at faster out of town speeds, which is due to exponentially more energy being wasted as heat within the battery at higher current draw.

Do you have any source on the 31.2kWh? I haven’t researched it so not sure, all I’ve heard is 28-29kWh from Tesla Bjørn’s review, which is at 90kmph. Which then decreases even more at 120kmph.

You sure the extra ~2.2kWh isn’t from the regenerative braking when driving around town?

[Trykpaa]

You sure the extra ~2.2kWh isn’t from the regenerative braking when driving around town?

That sounds very reasonable. When I measure I typically get ~27kWh usable battery.

[advance2020]

I agree with keithr "There's actually about 31.2kWh available (88% of 35.5kWh)"
All my Energy Usage stats and analysis is based on a Useable Battery capacity of 31.25kWh. This figure works for me.
It is calculated from what my car says its AVG m/kWh consumption is, Miles driven and how much % has been used up for each journey.
I have logged every journey in detail from Day One. Sad, but true.

Don't understand why Keith says Usable Battery Capacity varies according to how you drive it? I haven't seen any difference between hot and cold weather. Yes AVG m/kWh varies, of course - Autumn/Winter 2.4 to 3.6 - Summer 3.9 to 4.3 - but then you use more or less % Battery - so it always stays at 31.25kWh

In practice, this figure is only of interest to those of us obsessed with analysis.
All you need to you know on longer journeys is where your nearest (100% reliable) charger is.
And as a rough guide 1 Mile uses 1% of battery

Getting back to the topic, repeat - I have never seen any % Battery Loss, while car is parked up and idle.

[keithr]

Do you have any source on the 31.2kWh? I haven’t researched it so not sure, all I’ve heard is 28-29kWh from Tesla Bjørn’s review, which is at 90kmph. Which then decreases even more at 120kmph.

You sure the extra ~2.2kWh isn’t from the regenerative braking when driving around town?

Good point (although it's a 2.7kWh difference). The 31.2 and 28.5kWh figures were what I calculated from my driving last September (when the weather was warmer). [I checked my figures rather than relying on memory, and it was actually 28.7kWh rather than 28.5.]

Bjorn tested many electric cars at various cruising speeds and concluded that some battery capacity is lost due to heat generated in the battery at higher speeds (with the Honda being worse than average, presumably due to a higher battery internal resistance compared to the average).

However, explainthatstuff.com says that with regenerative braking, "Cars vary in what they can save from about 8–15 percent (depending on the car and whether it's driving in city traffic or the open highway)", and they estimate an average of 10% overall. Without some instrumentation in the Honda indicating how much regen energy is produced (like in the Nissan LEAF which can display the number of miles of range added due to regen), it is difficult to know how much of that 2.5kWh difference is due to the different amounts of regen. But I think you may be right that the majority of it might be down to the extra regen, so perhaps (pure guess!) about 83% of the battery capacity is availabe rather than my prevous guess of 88%.

[Edit]
Hang on a minute though. (My brains beginning to hurt now!) I presume the car displays miles/kWh based on how many miles it travelled and how many kWhs it started and finished with, i.e. starting and finishing state of charge. Therefore more regen will give a higher miles/kWh figure, but the miles travelled divided by miles/kWh will give the total number of kWh consumed from the battery, not battery consumption and regen combined. Therefore I was right to start with and the difference in available battery capacity is down to the increased battery heat losses at higher speeds. I'm not having a very good day!

[londiniumperson]

Charging the E to 100% should not be an issue. Having 28kW ish available from 35.3kW suggests actual SOC can only operate between 10-90%. Cars % readout is calibrated 0-100% over 80% of actual battery.

There's actually about 31.2kWh available (88% of 35.5kWh), at least when the car is driven around town. It drops to about 28.5kWh when the car is driven at faster out of town speeds, which is due to exponentially more energy being wasted as heat within the battery at higher current draw.

I also concur with a value of 31kWh
Having kept every charge record (plus more) & removing the lower & upper outliers of my stats this the average.
I'm basing these stats on the battery % at the start & end of each charge and amount of charge taken, not the indicated m/kWh, so this takes into account all power used irrespective of driving or pre-heating.