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Do I need another powerbank? Answered

If I have 2 devices that are rated for a maximum current of 4.5a and a powerbank which puts out a maximum of 4.5a, would both devices run off of the powerbank at the same time or would it need a 9a output for that to work?

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jeff.verive
jeff.verive

9 days ago

Two devices that are rated for 4.5A *may* require up to 9A, but this would happen only if both devices are pulling their maximum rated current at the same time. Whether this happens at all really depends on the devices themselves.

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ambientvoid
ambientvoid

Reply 9 days ago

The devices in question are 50w audio amplifiers. I decided to check them against a 23.5w amplifier I have and that one is rated as 5.5a, it seemed odd to me that a less powerful amplifier would have a higher current rating so at that point it occurred to me that perhaps I'd misunderstood and the ratings might be for a peak current spike rather than constant pull. I found a watts to amps calculator online and it said that the 50w amplifier should only pull 2.5w, and the 23.5w amplifier should pull a bit under 2a so do you think there would be any issues with running two of either amplifier off of my single powerbank?

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Jack A Lopez
Jack A Lopez

10 days ago

I suggest measuring the current drawn by your devices, rather than trusting the numbers printed on them, because these numbers tend to be overrated.

Also note the current a device draws, depends, on what is doing, how much power it is using, how hard it is working... if it is a device capable of doing more than one thing; e.g. sometimes it is "sleeping", sometimes "idling", sometimes "working really hard."

Also the current ratings for devices that supply current, tend to be overrated as well. This means, perhaps, your 4.5 A powerbank is comfortable at 4.0 A, but slowly cooking itself to death at 4.5 A.

I guess that means your best hope, for running your two, whatever they are, devices simultaneously, is if their current draws do not sum to greater than about 4 A, or 2 A per device, in the case where each device draws about the same as the other.