bobakka
Posts: 36
Joined: Mon Nov 03, 2014 8:03 am
Location: Oslo, Norway

Voltage for 1 bar

Sat Oct 28, 2017 12:02 pm

My iMiev just passed 135 000 km last Monday, and still doing great.

I tested with EvBatMon in September and got a reading of 67,92% batterycapacity left.

However, I believe the rest capacity is higher - maybe up to 75%.
I think the BMS was reset when I changed the 12V battery in January and the BMS maintain the margins as for a new battery.

I have been using Canion for several years and have several readings for SoC at 17% (same as 1 bar).

This week the batteryvoltage was 323 V and lowest cell at 3,58V.
At 22.12.2015 the batteryvoltage was 307 V and lowest cell at 3,385.

Anyone can explain why total voltage and lowest cell voltage has significantly increased for the same SoC in just two years?
Normal development I expect to by that the voltages decreases as time go by.
iMiev; New Feb 2011; 119000 km January 2017

rnlcarlov
Posts: 59
Joined: Wed Apr 13, 2016 8:30 am

Re: Voltage for 1 bar

Tue Oct 31, 2017 6:28 am

I think the car might have made an adjustment to the battery indicator based on your current degradation.
Malm has reported that his car makes a capacity adjustment yearly. As his battery degraded with time, the car also adjusts how much Wh each bar is worth. In a new car, if you charge from 50% to 55% SOC, it should show around 620-630Wh on Canion. As the battery gets more degraded, that value decreases. Since the ajustment is made yearly and the degradation is gradual, soon after a recalculation you might see things like that. Since each bar is now worth less, you have used less of the battery to reach 1 bar. So the voltage now is a bit higher than it used to....

...until more degradation catches up to it.

bobakka
Posts: 36
Joined: Mon Nov 03, 2014 8:03 am
Location: Oslo, Norway

Re: Voltage for 1 bar

Tue Oct 31, 2017 9:52 am

rnlcarlov wrote:Malm has reported that his car makes a capacity adjustment yearly.


If I remember right his car made a positive capacity adjustment, not negative.
The positive adjustment comes from discharging to lower voltage for the same SoC
iMiev; New Feb 2011; 119000 km January 2017

rnlcarlov
Posts: 59
Joined: Wed Apr 13, 2016 8:30 am

Re: Voltage for 1 bar

Fri Nov 03, 2017 4:50 am

bobakka wrote:If I remember right his car made a positive capacity adjustment, not negative.
The positive adjustment comes from discharging to lower voltage for the same SoC


Maybe the last one was positive, but the older ones were negative. I'm talking about those.

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