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I reached a point of beginning to accept the Zoe's odd transmission noises. ( Zoe transmission noise, sounds bad, probably have to go... )
So I figured I'd better check out what it is like with charging, having not charged it yet (no need).
Firstly, they clearly haven't fixed all those high pitched noises during charging;
Still the high pitched noises at 10kHz and there is now also a steady whine at ~1500Hz.
Moving on to the charging.
After 7hr15min the car has gone from 4% to 89%.
Assuming the car has taken on 85% of 50kWh, that'd be 42.5kWh.
But after 7.25hrs it has consumed 53.7kWh. This makes the overall charging efficiency about 79%. If the battery were to actually be 52kWh (i.e. 85% of a usable 52kWh) that'd be a slightly better 82%, or if 48kWh usable, as seems more fitting, that'd be 76%.
All pretty bad numbers.
Why?
Well, I wasn't expecting that it'd run the AC on 7kW charging, for sure.
This causes the charge rate to cycle up and down between 6.4kW and 7.4kW at times.
A charge rate of 6.4kW x 7.25hrs = 46.4kWh, so if the car has taken on 42.5kWh then the actual battery efficiency is 91%, which is perfectly respectable. But it means the AC cooling has consumed 7.3kWh all on its own.
The ambient has been 12C overnight.
I guess because the battery is so dense, a much more voluminous lump of mass with smaller and fewer cooling routes possible for such a cell density, it has been designed to have almost continuous cooling at 7kW?
I can't say I noticed the battery cooling whilst it was discharging at considerably higher rates, though. Seems like overkill to me to extend its theoretical lifetime, and a pretty considerable cost to the user.
So, Zoe's charging efficiency is around 76% to 82%, and one possible interpretation is that about 15% of the total input gets spend on cooling alone.
(These numbers are based on the one charge I have made so far, which is in progress now.)
If the charger is dumping about 1.5kW into the car that doesn't end up in the battery, this sounds like it could escalate considerably if the car is charged in a hot garage, in summer. The hotter the garage gets, the more power the AC draws which then heats the garage up further. It's one thing to cool the car a lot to help the battery (to save warranty issues, but at the client's cost), but have they thought about what happens in a confined garage space?
So I figured I'd better check out what it is like with charging, having not charged it yet (no need).
Firstly, they clearly haven't fixed all those high pitched noises during charging;
Still the high pitched noises at 10kHz and there is now also a steady whine at ~1500Hz.
Moving on to the charging.
After 7hr15min the car has gone from 4% to 89%.
Assuming the car has taken on 85% of 50kWh, that'd be 42.5kWh.
But after 7.25hrs it has consumed 53.7kWh. This makes the overall charging efficiency about 79%. If the battery were to actually be 52kWh (i.e. 85% of a usable 52kWh) that'd be a slightly better 82%, or if 48kWh usable, as seems more fitting, that'd be 76%.
All pretty bad numbers.
Why?
Well, I wasn't expecting that it'd run the AC on 7kW charging, for sure.
This causes the charge rate to cycle up and down between 6.4kW and 7.4kW at times.
A charge rate of 6.4kW x 7.25hrs = 46.4kWh, so if the car has taken on 42.5kWh then the actual battery efficiency is 91%, which is perfectly respectable. But it means the AC cooling has consumed 7.3kWh all on its own.
The ambient has been 12C overnight.
I guess because the battery is so dense, a much more voluminous lump of mass with smaller and fewer cooling routes possible for such a cell density, it has been designed to have almost continuous cooling at 7kW?
I can't say I noticed the battery cooling whilst it was discharging at considerably higher rates, though. Seems like overkill to me to extend its theoretical lifetime, and a pretty considerable cost to the user.
So, Zoe's charging efficiency is around 76% to 82%, and one possible interpretation is that about 15% of the total input gets spend on cooling alone.
(These numbers are based on the one charge I have made so far, which is in progress now.)
If the charger is dumping about 1.5kW into the car that doesn't end up in the battery, this sounds like it could escalate considerably if the car is charged in a hot garage, in summer. The hotter the garage gets, the more power the AC draws which then heats the garage up further. It's one thing to cool the car a lot to help the battery (to save warranty issues, but at the client's cost), but have they thought about what happens in a confined garage space?