Wednesday, 16 August 2017

Unstable / Surge Voltage for XL6009 Buck Convertor

Unstable / Surge Voltage for XL6009 Buck Convertor

I am new to electronics, and this small boost convertor has me baffled. It displays some weird behaviour. One sets the voltage using the small brass screw, but then if you watch and wait the voltage climbs from the set voltage, 5 Volts in my case up to 28v or higher. I have also observed the same behaviour when setting the boost converter to 10v.

This has resulted in me destroying a bluetooth amplifier, because after setting the voltage at 5V, and connecting the voltage climbed to 28v and killed the amplifier board (PAM8403).

I am powering the XL6009 board, with a headway 8ah LIfePO4 battery at 3.9V, which is rated for 100A output. So I do not think insufficient power is the problem.

If you have had any joy with this sort of thing O would appreciate some help.


  1. I've had the same trouble and managed to fry my USB voltage tester. I wanted to boost the voltage from an 18650 lithium cell (which was sitting at 3.7V at the time I was testing) and adjusted the output voltage to 5V. Everything was working fine, until I disconnected and reconnected my input source which caused the output voltage to jump up to 30V before settling down to 5V. I also observed the output voltage suddenly rising up to 30V without touching anything, but I think this was due to a spotty connection on the input.

    According to the datasheet of the XL6009 the minimum operating input voltage is 5V, contradicting the stated specs of the usual chinese sellers ("3 - 32V"). The output voltage didn't overshoot my set voltage anymore once I supplied the module with at least 4V (I adjusted the input voltage with an XL4015E buck converter), but I wouldn't count on this behaviour being consistent under different loads or even ambient temperatures.

    This boost converter unfortunately isn't suitable for boosting the voltage from a single lithium cell. It might be okay to use if you only connect the load after you let the output voltage settle down, but I wouldn't trust it.

    1. Thank you very much for your comment hopefully it will help other in the same situation. It is much appreciated. It is a shame the XL6009 is not more reliable at these low voltages.