Average energy usage during cold weather

[keithr]

that video, which shows that the VW ID.3 warms its battery pack up to 13C (whereas I believe the Honda e warms to 25C, although Honda don't give much detailed information!).

I'm curious to know where it's documented that the Honda heats the battery pack to 25C.

I would like to read some detailed technnical documentation from Honda too, but I'm not aware of any freely available (I did say "Honda don't give much detailed information!). I was getting the 25°C value from the animated video that used to be on Honda's website (see here) that shows battery cooling above 25C and battery heating below 25C. That and also data from this Chinese web page - EEWORLD which talks about the Honda e thermal management of the battery pack and states "The target temperature range of the battery is around 25-35°C, and the target temperature of other power electronics is around 55°C". They obtained the information from an SAE technical document which you can preview for free but the full document will cost $33 to purchase (which I'm not going to purchase!).

I've attached a diagram from that document below. (The top right graph is with the EWH - Electric Water Heater - turned off, the bottom right graph is with it turned on.) The Honda e uses the same cooling circuit for the battery pack, onboard charger and the DC-DC converter. It has two three-way valves that allows the cooling circuit to bypass the cooling radiator and/or to bypass the battery pack (second diagram below).

[milligoon]

Interestingly the motor is oil cooled and has it's own isolated cooling circuit

[londiniumperson]

Well if this is accurate & genuine Honda information then it must be correct, however it seems very odd for many reasons, not least that the document is very inconsistent, for example the left & right diagrams show the same information but are completely different, who in their right mind would do this, it would make more sense to use the same diagrams, also it is attributed to the 'WCX SAE World Congress Experience' event which Honda were not on the exhibitor, partners or sponsor list; It appears to me to be a group student course work project.

[londiniumperson]

I have just this moment read the following form the Chargemap blog:
https://blog.chargemap.com/5-tips-to-op ... news_en_38

In summary it states:

• An EV battery works best at temperatures between 20 and 25°C.
• At an ambient temp of -6°C compared to 23°C, an EV loses 12% of its range on average (not including equipment).
• When HVAC is taken into account along with an ambient temp of -6°C, the loss of range is about 41%.
• On average, a heat pump consumes between 500 and 750 watts whereas a conventional heating system eats up between 2,000 and 4,000 watts.

This aligns with what we have been seeing ourselves on the Honda.

[milligoon]

As we barely achieve 25C average in the UK that's us buggered then, best we crack open a few coal power plants so we can improve our range with the rise in temperatures

[Number5]

The Honda e is as brilliant as it is rubbish. Styling and driving is 2nd to none, efficiency is second to everyone.
The carwow vid was on a warm day and the e still took an early bath.

[milligoon]

Efficiency is not second to everyone.

Go to Bjorn Nyland's google sheets and sort by efficiency



It's not as black and white as it would appear this is a small battery (as you all should be very aware) even smaller usable capacity.

It's mainly down to battery range yes it's small

But it's not the least efficient in reality

[londiniumperson]

@milligoon
There's one notable issue there, temperature with it being significantly higher during the Honda test results than those with worse efficiency.
Also there seems to be a lot of conflicting Bjorn Nyland data on the internet, take, for example take this data from hs road tests:

[keithr]

the document is very inconsistent, for example the left & right diagrams show the same information but are completely different, who in their right mind would do this,

The picture is small and low resolution on that EEWORLD web page (it's higher resolution in the SAE document), but if you magnify it a bit you can see that the left diagrams are primarily showing the heat energy being cooled in the various components, whereas the right diagrams are primarily to show coolant flow.

[Number5]

I also have a kona 64kw and this performs much better than the e.

Drove both honda and kona over 35 miles to drop off one car.

Ambient temp 13°C, honda returned 3.6m/kWh with heating/AC off.
Kona returned 4.3 m/kWh with heating and air con on. Both from cold.
Same trip, identical drives.