Sjt2
Posts: 11
Joined: Tue Jul 01, 2014 5:49 pm

Electricity Consumption

Fri Jul 25, 2014 6:48 am

Hello Guys,
I am planning to get an i3 REx and want to know from the folks who have been charging at their home.

What is the typical KWh consumed for charging the i3?

I am sure it depends from person to person but any numbers to fully charge once will be helpful as I am planning to get solar panels installed and still trying to figure out how much consumption will i3 have.

Thanks in advance.

Blue20
Posts: 186
Joined: Tue Jun 17, 2014 2:12 pm
Location: SAE Combo (CCS) Deadzone

Re: Electricity Consumption

Fri Jul 25, 2014 8:11 am

According to the official specification, ...

BMW eDrive energy consumption in kWh/100 km 12.9

Say put on top 10-20% of energy lost during charging, that would be ~15 kwh /100km

Plug
Posts: 259
Joined: Fri Aug 02, 2013 1:17 pm
Location: UK

Re: Electricity Consumption

Fri Jul 25, 2014 8:20 am

Hi,

I've got a meter alongside my wallbox so I've been recording my consumption on a spreadsheet. The average charging losses (without pre-conditioning of the cabin) work out to be 17.1% and it doesn't vary much (chart of last 20 charges) which means that a full charge of the 18.8kWh battery from empty to full is 22.0kWh.

Would be interesting to see if that's similar to other owners who have recorded data.

Sjt2
Posts: 11
Joined: Tue Jul 01, 2014 5:49 pm

Re: Electricity Consumption

Fri Jul 25, 2014 9:54 am

Thanks Guys. That helps.

Say for a full electric charge, I get around 70 electric miles average

For about 15K miles/year, I see around 15000 *22/70 = 4714KWh.

That is roughly about 5MW.

This certainly helps in coming up with my solar panel system.

Thanks again!

Plug
Posts: 259
Joined: Fri Aug 02, 2013 1:17 pm
Location: UK

Re: Electricity Consumption

Fri Jul 25, 2014 9:58 am

Spot on :)

Don't forget though that some of your mileage will be powered via the REx and this obviously depends on how many long distance journeys you're going to be doing. I've seen some owners saying they haven't even used their REx yet, personally I'm using it for about 12% of my mileage so far.

Sjt2
Posts: 11
Joined: Tue Jul 01, 2014 5:49 pm

Re: Electricity Consumption

Fri Jul 25, 2014 10:11 am

Plug wrote:Spot on :)

Don't forget though that some of your mileage will be powered via the REx and this obviously depends on how many long distance journeys you're going to be doing. I've seen some owners saying they haven't even used their REx yet, personally I'm using it for about 12% of my mileage so far.


Hello Plug,
Thanks for the post! Yes. I didn't include the REx in my calculation as that will not be from my solar panel generated electricity :)
The 15K miles calculated with our family's commute distance /year + extra weekend trips.

I am totally in for a green 15K electrifying miles :)

Also, I read an article that REx drivers are the guys who are fully utilizing the electric miles as they don't have range anxiety and REx kicks in after fully utilizing the battery.

Plug
Posts: 259
Joined: Fri Aug 02, 2013 1:17 pm
Location: UK

Re: Electricity Consumption

Fri Jul 25, 2014 10:26 am

Sjt2 wrote:Yes. I didn't include the REx in my calculation as that will not be from my solar panel generated electricity :)
No, it won't be charged from your solar but it will reduce the amount of kWh's that you calculated. If you use the REx as much as I do then your answer is 4714x0.88=4148kWh.

If that's bleedingly obvious to you, apologies (maybe I've mis-understood and the 15k miles is what you estimate your pure electric mileage to be) :)

BrianStanier
Posts: 255
Joined: Sat Oct 19, 2013 12:00 pm
Location: Durham, UK

Re: Electricity Consumption

Fri Jul 25, 2014 11:45 am

I applaud your enthusiasm and don't want to pour too much cold water on it, but unless you live a part of the world with lots of sunshine and are able to charge your i3 only during the day and while the solar output is sufficient you won't be able to operate entirely on solar - perhaps not even mostly.

Zzzoom3
Posts: 214
Joined: Thu Jul 10, 2014 1:39 pm
Location: Ventura, CA

Re: Electricity Consumption

Fri Jul 25, 2014 11:54 am

BrianStanier wrote:I applaud your enthusiasm and don't want to pour too much cold water on it, but unless you live a part of the world with lots of sunshine and are able to charge your i3 only during the day and while the solar output is sufficient you won't be able to operate entirely on solar - perhaps not even mostly.
Solar Systems can be purchased with batteries that store the energy collected during daylight. So yes, sunlight is a requirement but the systems still function in overcast conditions. Only the amount of electricity produced is reduced.

Regarding energy usage, I have no doubt that what folks are reporting is accurate. You may also want to consider what the U.S. EPA calculated. The BEV model consumed:
30 kWh / 100 mi for highway
27 kWh / 100 mi combined
25 kWh / 100 mi city
Lou Perez
2005 E46 M3 Dinan Titanium Silver
2012 Volt Diamond White Tricoat
2014 i3 BEV Giga Laurel Grey Electronaut

Sjt2
Posts: 11
Joined: Tue Jul 01, 2014 5:49 pm

Re: Electricity Consumption

Fri Jul 25, 2014 1:04 pm

BrianStanier wrote:I applaud your enthusiasm and don't want to pour too much cold water on it, but unless you live a part of the world with lots of sunshine and are able to charge your i3 only during the day and while the solar output is sufficient you won't be able to operate entirely on solar - perhaps not even mostly.
Thanks for the info guys. Good discussion here.

The solar system (10KW) that I am putting generates 11MW per year (estimate).
Obviously more in summer and less in winter. Anything I generate will be fed to the grid and my consumption will be from the grid.

The electric company will only charge me for the (electricity consumed - electricity generated) portion.

At the end of the year, if the above is a negative number (meaning I generate more but consume less), they pay me back for the extra that I fed to grid (although it is pennies on the dollar because they charge me full retail while they buy from me at wholesale prices).

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