Vectrix NiMH Battery Pack Self Discharge after 4 weeks

Busy with another activity, I did not use my Vectrix in the last 4 weeks, and like it happened while I was on vacation, for the same duration, the Battery Pack shows a loss of 4 bars after 4 weeks, so it is like 1 bar per week

Also Voltage is showing 130V, and it is usually around 141-143 after a full charge, and the lower limit of 125V triggers the Red warning on the dashboard

So this time, I plugged it a full refill during the night 

Next morning, this is what I got: Fully charged and 139V

And 2kWh used to fill up ... I usually use 2.2kWh after a 5 to 6 bars use, so I was not very far from that

I then went for a good 25km ride and plugged it again to charge overnight

This morning, it shows 141V, so it is getting better I think

And exactly the same 2kWh consumption 

I will ride it like I did fro the last 3 years, having lunch with my former colleagues in Saint Ouen ...