Is the 5 volt USB supply from a computer clean

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Originally Posted by Cycleallday

I use one of these, along with a couple a similar ex Maplin batteries/chargers with all my Pi's and would not go back to any mains tethered device.

https://www.amazon.co.uk/HUAF-Portab.../dp/B07M6JFCLZ


The HUAF in particular is one i like - it has a quality feel, amazing battery life and can power 2x 2.5 amp devices and a 1x 1amp device at the same time should you wish.

Its a bit bigger and heavier than it may look - about the size of an iphone 6 plus and slightly heavier.

Its also good for charging my iphone and bluetooth earphones so gets plenty of use.

Mel

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Thanks Mel, that's an interesting alternative. Would I be right in saying that as its a battery in complete isolation there can be no distortion noise, or does the fact its a sensing charger mean there is something else electrical going on.

It is a 'smart' battery in that if the power draw is removed then the unit switches off. This i find useful as sending a power off command to the pi (via wifi) also switches off the battery.

I hear no degradation using this type of unit and would not move to anything else. I do have an Audiophinics linear psu but have not used it with the pi's since starting down the battery route.

Mel

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Originally Posted by Andy831

On the back of the OP question, if an item of kit asks for 5v 3a to power it is it ok to feed it 5v 2a or will that cause problems?

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Often the spec for kit in question will be over estimating what is required. I usually like to measure the actual current that the kit will take.

Also most Chinese power supplies over specify what you can actually get from them. The sellers presume that because it has a, say, 50VA transformer fitted then you can get V times A DC output power equalling 50, which you most definitely can't> There are losses associated with conversion from AC (the transformer rating) to DC (the output rating).
As a rule of thumb say 2/3 of the published current specification.

Thanks Alan

Sounds a bit complicated I will just buy a 5v 3a supply I think.

Andy