Vacuum Cleaners Discussions

hi, first think first im french. here goes my english: i have issue with my dewalt vacuum. model dcv581h. the one with electric cord and a battery too. so the problem is a voltage drop ( am i saying it right?). when it is turn on, and i am using it, the power goes down and come back to normal. the power goes down almost to turn off by itself, but no and come back to normal. anyway, it does that only when i use the battery mode. not with the electric cord mode. i cleaned the battery and the connection battery-vacuum, it helped a little bit. my vacuum is 1 1/2 years old. it happens after i clean my hair on the ground because i get myself a haircut. i hope u get a good read, have a good day