University Study needs Data Logging of kWh consumed

How can this be done with existing technology, or is something new needed?

TonyWilliams said:

How can this be done with existing technology, or is something new needed?

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Consumed from the wall or pulled from the battery?

From the battery while driving.

Ok, don't laugh, but could they use CarWings data? Mine was inaccurate until the very end, but perhaps it's better with the new cars?


Other than that, if you didn't want to use a CAN bus logger, I suppose you could install your own hall sensor on one of the high voltage wires coming out of the battery pack to measure current. Not sure where to plug in to measure pack voltage, but that I'm sure that a suitable place could be found. Where is Phil when you need him?

The way I've been doing it is monitoring the pack_volts, and pack_amps can messages and computing energy as integral over time of V*I*delta_time. It an be done either with a netbook connected to a gid-o-meter or in the meter itself with a simple change to the firmware.

I doubt Nissan would permit active CarWings monitoring, but I guess the researchers could get the info from the drivers.

Unless you have an early LEAF with the bad telematics firmware (and haven't updated it), kWh reporting via CARWINGS is accurate enough.

The web site allows you to download the usage records in monthly chunks. These can be given to a researcher.

TonyWilliams said:

I doubt Nissan would permit active CarWings monitoring, but I guess the researchers could get the info from the drivers.

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Yes, exactly. And if they wanted something more scientific, they could go the CAN bus route TickTock described above.

On a related note, I was hoping that Leaf owners could get a site similar to voltstats.net going, but now that GM decided to block access to their wireless data, the chances it will be done for the Leaf are slim. Presumably, you would share your CarWings login credentials with an independent website in this scenario, and they would communicate with the backend, collect raw data, and present it in a different way. They had lots of neat stats for the Volt, it was a really valuable resource.

# of miles driven / (m/kWh) gives you kWh used. Carwings with newer firmware gives good data.

I've data for last 19 months, I can share.

I'm going to direct the researchers here.

Hi, I'm one of the researchers from Cal Poly Pomona. To clarify, what we're looking for is energy use versus time with logged GPS coordinates at the same time. We want to be able to correlate the EV energy use with traffic data. Ideally we'd pull data directly from the Leaf data system (OBD2, CAN bus or whatever), log it, and download. We're currently doing this with an EV conversion using OBD2 and the Torque application running on a Android tablet. What I don't know yet, is if there's already a third party data capture/logging solution out there of if we need to develop our own. Any info you can provide would be helpful.

Bill, nice to meet you. There are several CAN-bus devices now, and an impressive amount of work has been done in this area. You might want to peruse some relevant threads below. TickTock, one of the most experienced CAN loggers, is already active on this thread. There are others you could reach out to: garygid, Turbo3, lincomatic, sparky (apologies if I missed anyone).

1. SOC Meter for One-CAN Logging & Graphing
2. WattsLeft™ Monitor (Parallax SX28AC/DP SOC/CAN Project)
3. SOC-LCD-Meter "LeafCAN" with 2x16 Display by lincomatic
4. Boards for lincomatic's open source "LeafCAN"
5. SOC-Meter CAN-Message and CAN-Do Log file formats
6. GPS data logging with CAN-Do
7. CAN bus messages

I don't know if my Carwings data is very useful.
according to Carwings I have never used more that 14 KWH in a day.

surfingslovak said:

Ok, don't laugh, but could they use CarWings data? ............ snip

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:lol: :lol:
:lol: :lol:
:lol: :lol:
:lol: :lol:
:lol: :lol:

grommet said:

Unless you have an early LEAF with the bad telematics firmware (and haven't updated it), kWh reporting via CARWINGS is accurate enough. . . . . . . . . snip

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Well mine's hideous . . . and I have every update - firmware too.

I am happy to help them get some suitable solution.
You may suggest that they call me.

Several Universities are using LEAF Logging Systems,
of one form or another, usually logging the EV and
CAR CAN buses, and GPS data simultaneously.

For Logging one CAN bus only, like the CAR-CAN bus
in the iMiEV, the OBDLink SX device used with my
CAN-Do program (or RealTerm to just Log) appears
to be a good, inexpensive solution.

I do not know if the Battery Park amps and volts
are available on the LEAF's CAR-CAN bus, but that
data does seem to be available from the EV-CAN bus.