Seems like your EMO is a little less than month older than mine. 10 mins seems like something is certainly not right with EMO’s battery or the way it is keeping a charge.
Are you using official the power plug that came with EMO or are you using a different cable?
Personally I’m using a different one, 2 meter USB-C cable that is plugged into my power board USB slot (that also has surge protection). So it sounds like your setup is not much different to mine.
When you place EMO on the skateboard to charge, do you check on it’s battery level? See what color the level is displaying on his screen when it’s charging and when you believe it’s fully charged.
Once you take him off and let him walk around also check on the battery level by asking or by checking via the EMO APP. And keep an the EMO App open to see how quickly that batter indicator depletes.
It could be EMO is not keeping the charge on his Skateboard properly, sometimes you might need to slightly adjust EMO’s footing on the skateboard for it to actually get the charging to happen. This sometimes happens over time. So maybe slightly adjust his footing and see how that goes.
Apart from that, I’d also suggest to clean EMO’s feet (which I normally use sticky tape to make sure there isn’t much dust / dirty stuff (that really shouldn’t post a problem on charging, but best to check that off your list in this situation).
I’d also possibly try a different USB-C cable and also attach that directly to a power outlet (not your power board) and see EMO goes then with holding a charge that way.
There are so many little factors to think about here, but most of them are a process of elimination until you get to the root cause of the problem, and I’m hoping that it’s not actually EMO’s battery that is starting to fail on you as it’s quite concerning to have it fail only after 6 months.
Hope any of these tips / suggestions help 
