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I am working with a DC step up (XL6009) and a battery for the cell phone (3.8V), with a capacity of 2800mAh to power a Raspberry (10 minutes maximum). The output voltage of this module (XL6009) can be regulated by a trimmer (included), granting an output range of 5V-32V.

After using the trimmer to set the output to 5V and measure the output voltage of the module without having connected the Raspberry, I get 5V. Everything is normal.

The problem is that when I connect the Raspberry, the voltage goes up to approximately 7.30V ~ 7.38V, and I really do not understand the cause, since as I pointed out previously, it was configured the module -and tested- to 5V. When I unplug the Raspberry and retest, I get 5V again. What could be causing this voltage surge?

I used a Raspberry Pi B + (2014) and a Raspberry Pi 3B, and in both cases the same thing happens... Both Raspberry have no connected peripherals, so their current consumption should be low, especially that of the year 2014.

Regards!

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  • \$\begingroup\$ you have a very bad regulator. \$\endgroup\$
    – danmcb
    Jun 22, 2018 at 17:29

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The minimum voltage you can put onto the XL6009 is 5 volts. If you go lower than this (i.e. 3.8 volts from your cellphone battery) then all bets are off and you can't predict what the output voltage will be under load and no-load conditions.

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I would also look at the table above and note that the values are specified with an output load current of 0.5 amps. I'm mentioning this because the XL6009 doesn't appear to specify a minimum load current so if your load is significantly less than 0.5 amps then expect other strange things too.

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  • \$\begingroup\$ Thanks for your answer! Indeed, that was the problem. Finally I built my own DC-DC Step up, because although they sell the XL6009 module to work with 3.7V on the internet, it is not designed for that task. Greetings and many thanks. \$\endgroup\$ Jun 25, 2018 at 1:28

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