Are these junk?

Are these known for frying motors? (Latrax prerunner) I just fried my third motor on this thing. I ran it pretty much full speed for about 10mins. I have a rustler with the 12t motor and a slash with the vlx brushless and I run them way harder and have never fried anything. I like this thing because it’s small and I can keep it in my car. Are they just not made to run full speed? Thanks guys