I picked up a Kobalt yesterday ($45 at Lowes) & ended up returning it today.
My MH is less than a month old & this was my first shot at topping off the tires. This could very well be "user error", but I struggled with it.
The unit did great to start with. My very cold tires (it was 23 degrees) started at 71 psi & I needed to get them up to 82 psi.
After 8 minutes or so, I was at the magic number. I had to overshoot the number on the unit to get my hand held gauge to come out right.
Basically, I had to set the unit to 86 psi in order for my gauge read 82 psi.
But, no big deal.
The manual said to run this unit no more than 10 minutes & then let sit for 10 minutes to cool down. So, that's what I did...we both came in to warm up for 15-20 mins., maybe a little more.
Second tire went OK as well, again 8-9 mins. We took another warm up break.
Third tire took the full 10 mins, so I stopped it... my hand held gauge read 81 psi, so I was ready to move on.
Every tire was registering at 71 psi initially. Makes me wonder what the dealer had them set to when I picked it up a few weeks back.
But on the 4th tire, the unit just ran & ran....no air seemed to be pushing through. I thought maybe I had a valve issue with the 4th tire, so we moved onto tire #5.
Same issue..the unit ran, but the digital PSI on the unit wasn't moving. If anything, I'd drop a half of a psi.
I had a decent extension cord, unit didn't feel hot, cord wasn't hot.
I will say one big difference was the first two tires were on the passenger side, close to the outdoor outlets, so I used a shorter extension cord.
Tires 3, 4, 5 were on the driver's side, so I got a longer cord & slid it under the MH to get power from the passenger side. Maybe the longer cord is the culprit? But, does that explain why Tire #3 worked?
Or maybe, I just asked too much of it...the extreme cold & changes in temp might have been too much for the unit. Maybe I tried to put too much air in it?
But either way, I took it back to Lowes and they graciously refunded my money.
Not wanting to drop > $200 on the air compressor, I decided to order the Porter Cable 1.5 gallon unit from Pep Boys for $100 (delivered to stores, must pick up in store).
Hopefully I have a little better luck with that unit.