Brother PT-E300VP -tarratulostin

I’ve had this now for four months and it’s been great, but the battery is next to useless you can charge it up don’t use the machine for a week and it’s flat again and this isn’t one of the old style batteries this is a lithium ion battery so it shouldn’t discharge that quick unless the machine is draining it ? Be cautious of this when buying.

I have made several attempts at registering my P-Touch E300 on the website and cannot get past the purchase date, I just get an error code.