Correct Xiaomi MiBox S Power Adapter

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outdoorsnz

674 posts

Ultimate Geek

#295341 22-Mar-2022 16:21

Decided to ditch the DishTV Android box due to sound levels gradually reducing until you reboot!

I shifted in a rush and all my electronic bits and bobs managed to get split between a few boxes.

I purchased the MiBox S from PB tech and pretty sure they supplied a NZ power supply.

The specs for the MiBox says 5.2v and 2.1amps.

Have found two power adapters that are close:

1. Samsung travel adapter - 5V and 2A.

2. Switchwerk travel adapter - 5.2V and 2.4A. But I think this one was for the google chromecast 4K from 1-day.

Which is correct? Concerned #2 could break the unit.

Currently powering with the MiBox 3 power supply which is 5.2V / 2.1A.

Thanks

robjg63

4096 posts

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#2890227 22-Mar-2022 16:39

The amps output is just how many amps the charger can supply.
If it said 3A on the charger, the device would only take what it needs.

If the power supply can't supply enough, the device may well keep rebooting, or not boot at all.
Beware that phone chargers are sometimes 'smart' for fast charging, and while it may show as having plenty of amps available, may only output that to a phone. I had that problem with a Samsung phone charger a vendor sold with a chromecast with google tv.

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SCUBADOO

192 posts

Master Geek

#2890230 22-Mar-2022 16:41

I have both the 3 and S boxes powered via 12V - 5V USB outlets in our motorhome.

Either of those adapters will be fine. I have tested both boxes with 5 - 5.5VDC.
Maximum draw is about 1.3A so any adapter rated 2A and higher will be fine.
I note that PBTech list the Switchwerk USB SW12AU 5V 2.4A for $10.50.

outdoorsnz

674 posts

Ultimate Geek

#2890257 22-Mar-2022 17:36

robjg63: The amps output is just how many amps the charger can supply.
If it said 3A on the charger, the device would only take what it needs.

If the power supply can't supply enough, the device may well keep rebooting, or not boot at all.
Beware that phone chargers are sometimes 'smart' for fast charging, and while it may show as having plenty of amps available, may only output that to a phone. I had that problem with a Samsung phone charger a vendor sold with a chromecast with google tv.

OK that makes sense on the Amps side. Both should work fine. But crap it I left the USB adapter cable back at home as currently staying at another property.

But lets say you found a random charger that wasn't a smart device and said 12V output (the DishTV charger does 12V / 1.5A). I'm assuming this wouldn't be safe? i.e. burning plastic smells...

Just want to clarify for others reading this.

SCUBADOO

192 posts

Master Geek

#2890261 22-Mar-2022 17:53

Nooo!
Must be c5VDC output. The smoke is more likely to emanate from the MiBox with 12V applied.

outdoorsnz

674 posts

Ultimate Geek

#2890262 22-Mar-2022 17:57

SCUBADOO: Nooo!
Must be c5VDC output. The smoke is more likely to emanate from the MiBox with 12V applied.

Yes as I thought! Just wanted that clarified in case someone misinterpreted smart chargers vs standard power supplies :-)

neb

11294 posts

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#2890827 23-Mar-2022 16:07

5V will be fine, the voltage is specced at 5.2V because most crappy cables drop the voltage enough that what turns up at the device is 5V even if it starts as 5.1V or 5.2V. Check a USB power supply with a high-impedance meter, it'll probably be 5.1V or even more to precompensate for cable drop.

So any 5V supply with sufficient power rating should work, which any modern supply designed to drive tablets and fast-charging phones will handle. From a quick search on the Mi S is has a barrel jack connector, so a USB -> barrel jack cable from a USB power brick should do the job. If you're in Orkland near the north shore I may even have one in the cable collection you could grab.

outdoorsnz

674 posts

Ultimate Geek

#2891407 24-Mar-2022 14:52

neb: 5V will be fine, the voltage is specced at 5.2V because most crappy cables drop the voltage enough that what turns up at the device is 5V even if it starts as 5.1V or 5.2V. Check a USB power supply with a high-impedance meter, it'll probably be 5.1V or even more to precompensate for cable drop. So any 5V supply with sufficient power rating should work, which any modern supply designed to drive tablets and fast-charging phones will handle. From a quick search on the Mi S is has a barrel jack connector, so a USB -> barrel jack cable from a USB power brick should do the job. If you're in Orkland near the north shore I may even have one in the cable collection you could grab.

Thanks for the offer, but at opposite ends of the country :-) Had my multimeter in the car, so just checked the older US power supply and at exactly 5.2V. Have at least one USB->Barrel connectors AND will play it safe and double check it is the correct polarity.

Not a 100% sure how to measure current on a power supply. I connected black to COM and red to Yellow 10A unfused. Then red tip to middle of barrel and back to outside. Reading jumped around so suspect device needs to be connected.

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neb

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#2891521 24-Mar-2022 18:24

outdoorsnz:
Not a 100% sure how to measure current on a power supply. I connected black to COM and red to Yellow 10A unfused. Then red tip to middle of barrel and back to outside. Reading jumped around so suspect device needs to be connected.

They're almost universally centre-positive, so polarity shouldn't be a worry. My random guess for the odd readings is that you're presenting close to a dead short across the output and the power supply is going into self-limiting.

In terms of power, I would be surprised if the MiBox drew more than 500mA or so, maybe they've specced the power requirements to deal with people plugging in USB hard drives or something? I've got a bunch of USB-powered devices fed a power brick with voltage and current displays and I think the highest-load device draws 0.3A. In particular one with a 1.5A power supply draws 0.2A at full load, most are 0.0 to 0.1A.