OnOff shim maximum current, stacked header, Pibow coupe?


Searching the product page for the OnOff shim, and this forum, I couldn’t find answers to my questions, so hopefully someone here can answer them:

  1. What is the maximum current the OnOff shim can handle? Does it allow a Pi 3B with official 7" Touch LCD? Does it handle 2.5A?

  2. When using a stacked GPIO header, but not the extra tall one, with 10/11mm headers, can I use the OnOff shim with such a header, place a pHAT or HAT on top with its own female block, and does this still fit with a Pibow coupé casing? (the pictures suggest that the Pibow coupé works, but I want to be sure with using an extension header…)


The OnOff shim will handle 2.5A yes. It’s designed with the official Pi power supply in mind.

I’m not sure about the stacked GPIO header- my brain is mushy today and I’m having trouble visualising what you describe :D (and, of course, have none of the above to hand to test it :D)


What if I have a power supply of maximum 3A?
Can I expect to fry it or any other side effects?


You aren’t advised to use 3A power supplies with a pi. I don’t know whether it would work. If you try it you may be subject to magic blue smoke though!




The Pi will only draw what current it requires from the power supply. You could use a 5A supply so long as it’s only giving 5v.




supports up to 2.5A power supply

is what it says on the product page and to be honest I am more or less talking from that.



Ah that’s different to what you put in your post which stated “you arn’t advised to use a 3A power supply with a Pi”.

You can use a 3A supply and there is no reason why you shouldn’t, however if you are powering the Pi via the on/off shim then it is only rated at 2.5A. Should the pi draw more than 2.5A due to any added peripherals then you could have an issue.