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Renault Zoe Intens 2013
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Discussion Starter #1
My Zoe 22kw SOH (state of health) has actually increased for me - a few weeks back with CanZE I tested and it was 90% ... just checked today and its 92% now. Not complaining, was just glad to see the SOH figure had gone up ... but have no Idea why, the weather is gettng colder but I shouldnt think that has an effect on anything?

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I have found SOH can improve slightly after a few full charge cycles charging from low SOC to full.
 

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What mileage has your Zoe done? - 92% sounds pretty respectable for a 7yo Zoe.
 

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I don't mean to be the bearer of bad news but I found that a small increase in SOH usually was a fore runner to SOH dropping again. You'll think you've got lucky when it drops to 90% again, but don't get too exited give it a couple of weeks and it will dip another 1%. :(

You might see a double rise in SOH, but again it will soon dip again.
 

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Discussion Starter #7
I don't mean to be the bearer of bad news but I found that a small increase in SOH usually was a fore runner to SOH dropping again. You'll think you've got lucky when it drops to 90% again, but don't get too exited give it a couple of weeks and it will dip another 1%. :(

You might see a double rise in SOH, but again it will soon dip again.
Ah well, never mind .. you little ray of sunshine 😄
 

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Co-author of CanZE. Q210 nov 2013
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SOH is "just a number, calculated by the computer". It's in no way a direct measurement of the physical state of things. The only thing the computer can do is measuring currents and cell pair voltages. Most battery management systems define SOH as the measured capacity of the battery in Ah (not kWh), divided by it's nominal capacity. Since the battery usually doesn't do full cycles, the BMS infers the Ah capacity based on voltage changes during (dis)charge. SOH fluctuating a bit is pretty normal. A few deep cycles will probably make it adjust faster / closer to reality.
 
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