Posts: 16
Joined: Tue Dec 29, 2015 10:25 am

Interpreting a battery capacity test

Tue Jan 19, 2016 11:43 am

I am considering purchasing a 2014 iMiev in Halifax, NS. The car is a demo, with 500kms. I asked for a check on the battery capacity. The results were: test 784 Battery Capacity Secular Deterioration 5.06% and test 785 Battery Capacity cycle deterioration .19% Could someone kindly help me understand these results? I am obviously interested in how much capacity loss the battery has. How should this effect the amount I would offer for the car? Thanks for any help.

Posts: 1158
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: Interpreting a battery capacity test

Wed Jan 20, 2016 9:20 pm

Those terms of description of the tests do not sound familiar to me at all--the service manual has procedures for using the Mitsu Universal Tester, aka the MUT, to measure the capacity, both from values stored in memory, and by doing a battery drain and recharge test. Maybe those are from the stored data, but i've just never heard of it like that.

A quicker and better option might be to find a member in the local area who has the OBD reader and the CanIon android app on their phone. In less than a minute Canion can display a nice bar chart graph showing the voltage of all the cells in the pack. If a cell is defective it will be out of line with the rest.

Ask about how long the battery is covered under warranty--if it has the 10 year then it is covered no matter what the test data shows, i.e. not a worry. Try to get the best deal you can, but you will love driving it so much that you can't get the grin off your face...
kiev = kenny's innovative electric vehicle

Site Moderator
Posts: 3894
Joined: Thu Dec 15, 2011 5:47 am
Location: Silicon Valley, California

Re: Interpreting a battery capacity test

Thu Jan 21, 2016 10:22 am

I agree with kiev as this is also the first time I have heard of these specific test numbers and descriptions..

Had to look up the meaning of secular, as I hadn't heard its use in the context of battery capacity. Found this use in Economics:
"Occurring or persisting over an indefinitely long period." Example: there is evidence that the slump is not cyclical but secular.

Certainly a good bargaining chip for you in negotiating a price, but I also wouldn't worry about it as so far Mitsubishi has been very good about honoring the battery warranty.
kiev wrote:... Try to get the best deal you can, but you will love driving it so much that you can't get the grin off your face...
A few weeks ago my next-door neighbor bought a used i-MiEV to complement the Leaf he's had for four years which he gave to his daughter - he can't get the grin off his face praising the i-MiEV's sprightliness!
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

Return to “Batteries and Battery Management”