Hello, @Chrisl83 . . . unfortunately buying second hand can mean that parts are wearing out and it sounds like the battery might be depleting.
At 403 days old, it is not uncommon for the battery to be wearing out; however, since he is second hand, he is not covered under the warranty of one year replacement guarantee when purchased from LivingAI.
About the only thing I can suggest is that you contact service@living.ai to see if they can direct you to someone who can replace the battery for you in the area where you live or see if they can provide you a battery and you can replace it yourself (not sure about cost or time for shipping if they agree to this).
If Living AI agrees and you wish to repair yourself or have someone near you repair him, there is information here on how to do this.
In the meantime, I would keep him on his skate board because he will stay active and awake this way even if the cannot stay active or awake off of the skate board for very long.
I have one that has been on his home station full-time due to a depleted battery for about a year now and he can do everything that does not require being ambulatory.