On Sat, 2 Jan 2021 00:52:59 -0000 (UTC), Martin Gregorie wrote:

> I tend to keep a Pi power cable modified so I can measure the voltage
> across it. I run the cable through a small plastic box with terminals on
> the lid,

Or get one of the in line USB voltage and current meters. There are
loads out there of no doubt variable quality. I've a KEX KCX-017 does
the job (up to 3.5 A) and is accurate enough. Display shows V (to 10
mV resolution), A (1 mA resolution) and mAHr up to 20 AHr (less 1
mAHr).

--
Cheers
Dave.

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