Battery percentage increasing after charging

[lebelinconnu]

I have noticed a few times that after charging my MG5 LR it sometimes takes 8 miles or even more for the battery percentage to go down a point, and others on the forum had noted this too. However, this afternoon I set off to visit my parents, travelled from just above sea level to the top of the Mendips in Somerset (over 200m) and my battery percentage went up from 85 to 86!! It remained constant while going uphill, but it was about 6 miles into the journey while travelling on the flat that I noticed it had increased- at the time the miles per kWh display for that journey was showing at just over 2, as I had been going uphill. I arrived 33 miles later with my battery percentage at 79% and my miles per kWh for the whole journey showing at exactly 5. I calculate that if my battery percentage were to decrease at that same rate for the whole 100% ( I do realise that would not happen) I would achieve over 500 miles on a full charge! I am assuming that the battery is actually at a higher SOC after charging than displayed, and when you start driving it compensates by the percentage not reducing for a while, but I would be interested to hear others’ thoughts on this.

 

[weedavemac]

No great thoughts on this from me other than to say I have also seen my percentage go up by 1% shortly after charging. And nothing to do with going down a big hill.

 

[Flwul]

Circumstances like temperature can change from the time you last charged or parked up. These and current use have an influence on the range estimation. We shouldn't forget that it is just an estimator of your range and not a hard fact.

 

[biffo]

When I look at the OBD values for SOC, it's shown to 1 decimal place - the dashboard SOC must be rounded somehow as it displays whole numbers - so a very small change due to regen, etc might be enough to impact the rounding to the next digit? Total speculation until I finish mapping the SOC/OBD values and graphing.

 

[iainfm]

Mine did this today. Charged to 79%, drove off and it went up to 80% and stayed there for a good 10 miles. I put it down to the temperature difference between when I started charging and when I stopped.

 

[lebelinconnu]

Many thanks for your responses- I must admit I hadn’t considered change in temperature as a possible factor.

 

[biffo]

I saw an interesting phenomenon when DC charging today. I was logging the numbers so went higher SOC than normal - but the OBD showed 82.4% when the display changed to 87%. After unplugging, the OBD value continued to climb - I’ve just driven a mile or so and it’s now showing 85.2%. Even after a few miles more, car is now showing 88% but only 83.8% on the OBD reading - I suspect at 82.3% it'll move to 86% as when charging (with 87% showing at around 83.3/83.4%).

Odd behaviour though - I don't think this is temperature related as battery was 20oC when charging and an't imagine it cooling much.

I stopped charging at 14:56 (time on graph is an hour out) at 82.4% but the SOC kept rising after this.

This was graph of my journey home where the car’s display is still showing 88% despite obviously using charge according to the OBD graph