WetEV
Posts: 2262
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

CHADEMO based battery testing

Wed Nov 22, 2017 7:58 am

I'm wondering how much market there would be for a CHADEMO based battery testing service.

Thermal soak the car to a known temperature, charge the car to 100%, plug in the tester to the CHADEMO, controlled and measured discharge to a low charge percentage, verify cell voltage balance, and print a nice report.

It seems like this might be valued by a car buyer or seller as the condition of the battery is both important and how to know.

The thermal soak would be required to get a consistent test. Batteries hold more energy at higher temperatures. So put the car into a garage with a big fan moving air over the battery. Could just be controlled temperature air for long enough. Charge to 100% with L2 sometime late in the temperature soak. This process might take a couple of days.

The tester would set up a V2G session at a moderate rate, say 0.4 C, and discharge from 100% to 20% (or something like that). Circuit would include a calibrated voltage and current logger. Probably best to use a measured voltage to set the end of discharge, rather than the car's reported SOC. This process would take a couple of hours. Perhaps something like this:
viewtopic.php?p=511926#p510938
With a pass through CHADEMO cable with voltage and current monitoring.


The report is "just software" and I can see an ex-boss chucking while I write that, but would be key to the customer.
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red

User avatar
Marktm
Gold Member
Posts: 417
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737
Location: Houston, TX

Re: CHADEMO based battery testing

Tue Apr 24, 2018 1:28 pm

Would you expect the results to be significantly more accurate than the Leafspy results of amphours/GIDS/voltage readouts and extrapolating to the full energy from 100% to 0% charge? An interesting load test idea! Not sure anyone has an accurate SOC curve for the particular cells in a specific year Leaf? I'd like to see for my "Lizard" battery - the full 100 to 0% with various "C" and temperature curves.

Another question - does the new 2018 Leaf support bidirectional energy via the CHAdeMO port? Has anyone designed such a bidirectional energy converter using 240 VAC split phase in/out? Princeton Power makes a commercial unit - don't know anyone that has actually used it. If I'm not mistaken, the PP can also work with 480 VAC 3 phase.
2012 Leaf SL; 36,000 miles. Battery replaced November 1st, 2016.

SageBrush
Posts: 2695
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: CHADEMO based battery testing

Tue Apr 24, 2018 2:22 pm

Most dealers and buyers set the car price by the odometer, year of manufacture, cosmetic condition, and "capacity bars."
They would have no clue what you are talking about.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
3/2018: 58 Ahr, 28k miles
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2018 Tesla Model 3 LR, Delivered 6/2018

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