nonoti wrote: ↑
Wed Sep 19, 2018 1:40 pm
There is the possibility that they can supply me with a custom connector to a 5V power rail that can do up to 3A per connection.
However, that rail runs at 5.2V not exactly 5V. Would this damage the Pi on GPIO?
The Pi is officially rated as 5V +/- 5%, 4.75V to 5.25V so your Pi should be okay and being slightly high will help compensate for any losses in the leads connecting from the rail to the Pi.
As to actual maximum voltage you can safely apply to the Pi beyond 5.25V; that depends on the model of Pi you have and what you have connected to it.
To work out what the maximum safe voltage of any Pi model is would require doing a full audit of everything which uses the 5V rail and that isn't easy with only reduced schematics published which don't show all components or connections.
For the Pi Zero and Zero W, with nothing else which uses 5V (HDMI/GPIO/USB) connected at all, the 5V rail appears to only be used by the 3V3 regulator (PAM2306AYPKE) and that should be good for up to 5.5V with an absolute maximum of 6.5V from the datasheet I have. And also good down to 2.5V though you'll be getting 'low power warning' all the time and the official view is that this is a fault condition and will adversely affect your Pi and SD Card.
For other Pi there is a SMBJ5.0A transorb fitted which appears to kick in around 6.4V. One could assume that other components, some not shown on the reduced schematics, would also tolerate that or the protection it offers is mostly illusionary, but it's hard to say.
For example the PMIC on the 3B ( and likely 3B+ ) appears to be good for up to 5.5V with an absolute maximum of 6V, so I imagine that could well be gone before the transorb kicks in.