Battery wear jumped to ~40% in 3 days

Hi,

I hope someone can help with this concerning Surface pro issue. I have a surface pro 4, I7, 512GB. I've had it for about 9months and I've been very happy with it, battery life has always been a little poor but I knew that before I got it and understand that this level of CPU power takes a fair amount of energy to power it.

I've been running battery bar for a few weeks just to keep an eye on how the battery is getting on and noticed today that it shows a wear of 41.5% (22,320mWh of 38,152mWh).

Here is the report generated from powercfg/batteryreport:



It shows that 3 days ago the capacity was 34,410mWh and now it's ~40% of that. I haven't done anything different to usual and this concerns me. the 5-6hour battery life was barely manageable if that were to drop to 40% of that my SP4 is almost useless to me.

Is there anything I can do or try to get it back again? does anyone know why it would have dropped off so quickly?

any help is massively appreciated.

Darren

 

some more info from the battery report: