Battery pack for microscopy on-the-go / uninterruptible power supply

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This is a trick I learned from making a DIY electronic mirror. You can power some hefty electronics, including screens and speakers, off of a powerbank that supports the USB power delivery specs. Tried it with a microscope, works like a dream. I’m able to move the motors, focus, take high res pics. I’m connecting to it from a computer right now, since I’m running a lite version of the image. In the near future, I’ll be trying it with a 7” 1080p touchscreen that I plan on integrating with the device, so I’ll run some battery longevity tests with that setup.

The specific powerbank that I know works is a charmast 26800 mAh, model number W2002P. It costs like 25 Euro, example link below:

https://allegro.pl/produkt/powerbank-charmast-26800-mah-czarny-3e786b34-8e99-4044-8c6f-436cab8da1d6

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To give some context about how this worked with the mirror - I was able to have the powerbank connected up to the socket and charge it, and use it as power for the mirror at the same time. It ran a chromecast, laptop monitor + laptop monitor driver board, some DIY speakers with a small amplifier in them that also used USB power. I think the battery lasted a day or two of it being on constantly? Overall very impressive performance for a random low quality battery for cheap.

Relevant vid about the mirror and its power delivery, with a timestamp:

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Thanks for sharing. Is this like an uninterruptible power supply?

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I just doublechecked, I don’t think that’s the case for the microscope unfortunately. I must’ve misremembered how it worked with the mirror, it’s been sitting in a cardboard box for years now. When I daisy-chain the powerbank (PC → powerbank → microscope) the microscope turns off and the powerbank starts charging.

Either that, or the mirror had something in it that allowed that to work, that the rpi doesn’t. I’ll check it out by the end of the week and see if that’s the case, and report back.

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I checked and I’m not seeing anything special on the mirror. It just has a usb-c powerboard chip to pull the required power to the mirror screen.

I read up on it, and it is a thing for specific powerbanks, that’s called pass-through. So as long as you can find a powerbank that is pass-through and has the power delivery capability, it should essentially work as a UPS. Do note, that it’d be constantly charging and that it is a battery that’s probably not meant for 24/7 use. I’d be careful about doing that and only use it / leave it plugged in when there’s someone nearby that can react when something goes wrong?

Edit: I just ordered a passthrough powerbank that should work. If next day delivery makes it, tommorow I’ll have updates on it.

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Yup, it does seem to work as a UPS, at least during the short test that I did. The only caveat is that it needs a fast usb-c phone charger, rather than the Raspberry Pi power adapter. On the Pi adapter, the microscope just wouldn’t turn on when the powerbank was dead (so I assume it’d just discharge the battery if it was full). I grabbed an old samsung charger that I had, the fast charging icon on the powerbank lit up. When I connected the microscope, the fast charging icon disappeared, but the percentage charge went up with the microscope connected. I then disconnected the charger and the microscope kept on trucking, seemingly with no interruption / reset.

The specific powerbank I bought is the Emos NTBF30, at 70 euro. It has two USB-C ports and a single USB-A. I connected the charger to USB-C input / output, and the microscope to USB-C output.
There is a cheaper, smaller version - the Emos NTBF20, which costs 35 Euro, it only has a single USB-C and a single USB-A connector. This is a similar setup to what I had earlier with the Charmast. I don’t see a reason why it couldn’t be used the same way.

Maybe the Charmast’s issue was that it wasn’t connected to a fast charger too?

For some numbers, the input / output USB-C is 100W, USB-A is 22.5W, and the USB-C is 27W. For context, a gaming PC that I’m on, with loads of apps running (steam, discord, firefox, open flexure connect etc) is currently drawing 95W as I’m writing this post, according to my UPS.

Also, the powerbanks that I used were the first ones I looked at on Amazon. There are probably cheaper, better, smaller ones out there somewhere.

I’ll charge up the battery to full, then see how long the microscope can run and edit this post. I’ve also changed the title to reflect that it can potentially be used as a UPS

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