Tracking i3 efficiency

[brianives]

I'm within a week or so of receiving my BEV i3 and am buying it primarily because of its efficiency (though I can't lie - I'll love the acceleration). How will I be able to track my overall efficiency? I understand that my Clipper Creek charger is not going to track the total electricity it pumps into my i3. Does the i3 do that? Will one of the apps help? I want to be able to know how many miles I get per kWh and track how much electricity I have used to power my transport over time.
Those of you who have had your i3s for some time, do you feel like you are being called upon to be ambassadors for EVs and efficient driving? And if so, I know I'd like to be able to share data about my own experience and electricity usage.

 

[Zzzoom3]

I started a thread about tracking usage you could look at:

http://www.mybmwi3.com/forum/viewtopic.php?f=11&t=1220

 

[KurtEndress]

The i3 will certainly give you an efficiency figure for at least your current/last trip. My last trip came in at 4.1 mi/kWh over 11.8 miles. I’m not sure whether there is a grand total figure for the car’s life. I don’t totally understand how the trip odometers work yet, I think there are two of them. I’ve only had my car two days so far.

If you want to track the amount of wall power going into the vehicle (total system efficiency) rather than what comes out of the battery, there are ways to do that even if the EVSE won't. You should have a look at The Energy Detective http://www.theenergydetective.com/

I’ve had a TED 5000 hooked up to my electrical panel for a few years to track my whole house energy use. I may have to buy an additional MTU/CT set for $85 to track the energy being used by the new 240 volt circuit to be installed for the EVSE. Then I could get hourly, daily, or monthly reports on how much power was used by the house and separately the EVSE. Or I could spend $500 upgrading to a TED Pro Home with the capability of monitor 2 240V circuits and 6 120V circuits. Then I’d really know where the power was going. I’m not sure I really want to know how much power I’m using on the central AC though. I already know that it’s between 10 and 40 kWh a day. The i3 will not be the biggest user of power in the house during the summer.

 

[ultraturtle]

How will I be able to track my overall efficiency?

Plenty of options to measure wall to vehicle consumption:

Cheapest would be a simple Wh meter in line with the EVSE circuit: http://www.theenergyconscious.com/v...zSgJcHa4HTPH2wrZIiHYsBCT7YcCmwz_cgaAsBL8P8HAQ

Next step up would be the hundreds of devices that look like this: http://www.ekmmetering.com/ekm-mete...-100a-120-240-volt-3-wire-60hz-ekm-25ids.html

or simply break out one of the two power lines supplying the EVSE to run through a cheap clamp on ammeter.

The most practical, however, is T.E.D. : http://www.theenergydetective.com/. Used by hundreds of EV enthusiasts by now.

Simply divide the Wh consumed by the miles actually travelled between full charges to come up with a true W/mi figure.

 

[AviatorMan]

I'm within a week or so of receiving my BEV i3 and am buying it primarily because of its efficiency (though I can't lie - I'll love the acceleration). How will I be able to track my overall efficiency? I understand that my Clipper Creek charger is not going to track the total electricity it pumps into my i3. Does the i3 do that? Will one of the apps help? I want to be able to know how many miles I get per kWh and track how much electricity I have used to power my transport over time.
Those of you who have had your i3s for some time, do you feel like you are being called upon to be ambassadors for EVs and efficient driving? And if so, I know I'd like to be able to share data about my own experience and electricity usage.

Hey Brian,
There is one other option you might be able to explore. It is very limited, won't work for some people, but might work for you and is dirt cheap. Get a P3 kill-a-watt meter for $28, downgrade your 120 volt charging option to the reduced (12amp) rate and charge off of a 120 volt outlet through the kill-a-watt for a day or two, or a week. Yes it will take all night to charge, or maybe longer, but if your commute is short you could pull it off. That would give you your average cost per week which is enough info to evangalize from. This solution will only work if your daily useage averages 40 miles/day or less.
Of course you can just say that the EPA estimated cost is 2 cents per mile, which where we live is how it works out.

 

[i3Alan]

Get a P3 kill-a-watt meter for $28, downgrade your 120 volt charging option to the reduced (12amp) rate and charge off of a 120 volt outlet through the kill-a-watt for a day or two, or a week. Yes it will take all night to charge, or maybe longer, but if your commute is short you could pull it off. That would give you your average cost per week which is enough info to evangalize from.

Keep in mind that L1 charging is less efficient than L2 charging. There is more power consumed by the charger's circuitry converting from 120VAC to over 360VDC than is consumed by the charger when the charger's input is 240VAC, for any given amount of battery charge. The battery is 360VDC, but charging requires a slightly higher voltage, which causes the current to flow into the battery in the correct direction.

That is, it will cost you more to fully charge your i3 at home with the 120V L1 EVSE than with a 240V L2 EVSE. My guess is that the difference is pretty small, probably within 10%.

On the other hand, if your house wiring is poor for the 240V circuit, but not for the 120V circuit, then the I^2R losses in the wiring from the house meter to the EVSE could be greater for the L2 than the L1 due to the greater currents for the L2, perhaps reversing the advantage. This is not very likely.

 

[brianives]

Thanks for all of the responses on this thread. I will explore a TED, which I have seen described before in Home Power magazine. Maybe now is the time to get it. I also have a Kill a Watt, but hadn't thought about charging the i3 for a short stint using 110. Great idea. I appreciate the collective wisdom here.