![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9WmNPxEJBj3ahJ_2oKLL14MmfDTlNkaziloV9rh9b6CluecKzPjn4ov8QtpTTcB7rCyJgfjaMhCxKILO3xgopJEsj0IBEcYiWwO1LcCgSnealRxKIrgjfCmw45_h9BZkgTczXQIKbxo0/s400/COIDO_COMPRESOR_AUTO_12_V_300_PSI.jpg)
I'm not sure what the 300PSI on the unit stands for it has nothing to do with pressure as the unit fails to pump around 30psi. Not that its easy to tell the exact pressure as the LCD pressure display is constantly jumping between 12psi and 55psi.
This 300PSI pump is clearly for air mattresses and balloons, not tyres of any pressure. Picture on the front of the box might show a car tyre but in my experience i lost more air from the tyre.
Perhaps the unit requires a little more voltage so i started the car then plugged the unit back into the lighter and attempted to inflate the tyre that is now lower in pressure after my first attempt.
Same kind of result, i have to start the pump before connecting to the tyre or the motor will just not pump. Now the LCD screen is blank and showing nothing but guessing from the state of the tyre it's not doing much. 5 Minutes later the unit is noticeably hot and the tyre looks the same. Removing the unit i checked the pressure to find it has once again lost pressure.
Data:
- Original test voltage 12.5v voltage drop after pump started was only .3.
- Engine running voltage was 13.7 with no voltage drop after starting the pump.
- Start pressure was 28psi, then 27psi, then just under 27psi respectively.