# How to deal with Raspberry Pi power supply?



## Tennywang (Mar 5, 2021)

Hello folks,
Recently, I’m building a remote (lives outdoor) scientific device that collects environmental data. I have an old original Pi B from about 2011 that I am using as an ethernet connected data logger. Everything works well on the bench - until I connect the internal 5V supply.

I have +12V available with plenty of capacity to run the Pi. (Currently running on a lab PSU so I can monitor voltage and current). The 12V feeds a 7805 regulator - - which admittedly gets warm but these are not the most thermal efficient devices in the world. I am getting a solid 5V out of the regulator and I have adapted a micro USB plug/cable only using the 0 and 5V power leads. The screen is tied to 0V.

The Pi does indeed boot up and all appears ok, except that all the USB interfaces and Network interface shut down a few moments after they startup. And it is bog standard except for a MCP3008 A/D converter plugged into the GPIO which is working well when I plug the Pi into a wall USB socket (the type which is a supplement to a 13A mains socket). i.e. nothing shuts down.

There is no significant increase in current when I plug the pi in, it should be operating well within the 1.5A capacity limit of the regulator.

Anyone has ideas of it? Many thanks.


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