I just got the same pump and tested it
dropped a tire by 15 psi and pumped it back up. Did not time it.
My handheld tire pressure gauge said the tire was at 40psi and I dropped it to 25psi… the airpump said that was 18psi.
I then set the pump to stop at 36psi, it stopped at 36.5, and that measured 43psi on my tire gauge… the gauge on the tire inflator reads low by 7psi…
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likes
the pump is rather quiet
the hose is long enough to easily reach the tire valve
the unit stands stable on the ground
the auto stop works great
love the battery operated feature, super convenient not to run power cords and not to run the motor.
there is a lighter cord coiled into the bottom of the unit and the hose also fits in that gap… convenient storage.
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room for improvement:
the pressure gauge in the unit reads 7 psi low
the hose got hot after 15psi, and battery dropped to 1bar
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When I did the test I had not fully charged the battery, though it was at 4 bars.
Immediately after the test it had dropped to 1 bar and a few minutes later it had rebounded to 2 bars.
Although I has originally considered doing a total of 40psi inflation test, I did not contiue the test after 15psi, to avoid overheating and overdischarge… I waited 1 hour for the unit to cool down, then plugged in to charge
Im not sure it is realistic to expect this little pump to put out a total of 40psi, without a recharge or at least a cooling break.
I like it and want to keep it, just for the convenience of adjusting my tires by 5psi, if not 10.
Am wondering if I should ask for a replacement with a more accurate PSI gauge?
@xevious is your tire pump PSI meter reasonably accurate?