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Very few USB battery banks can handle charging power being added and/or removed without "restarting". I doubt this works as the author intends: it almost certai

Very few USB battery banks can handle charging power being added and/or removed without "restarting". I doubt this works as the author intends: it almost certainly restarts as power comes and/or goes. Not relevant here, but many multi-port usb-c chargers also stop & start when you plug in or remove another device. Been a long term Ugreen fan, still use the incredibly generic looking 30W charger I bought absurdly cheap from them in 2019, but this behavior is definitely on the Nexode units I have from them (130 & 65W). I did get a OTAO 200w desktop charger & it maintains power as I add or remove devices, which is nice! My monitor runs off usb-c via a 20v DC barrel jack cable, so it's nice being able to plug in a laptop or phone without the screen resetting, ha.

vermaden 3y ago
That is true and I must sadly admit that I did not tested that ... after some more research I have found that ZMI QB826G 25000mAh powerbank has that 'ups' feature. I have already ordered one and I will test with that one. I also need to add some notice to the article that my first approach failed. Regards, vermaden
- jauntywundrkind 3y ago
  I just tried with my pre-ordered indiegogo "No. 20", which is the QB826 (no G). I haven't tried with a laptop yet, but my phone indeed kept steady power in to it when I connected/removed a charger from the power bank! Neat!! Indeed seems like some level of ups capability! Confusing naming, but I had & adore ZMI's earlier "20k" power pack. The new No. 20 is 25Ah/2 usb-c/210w, the old 20k Pro is 20Ah/1 usb-c/65w(+ 2 decent usb-a)... But damn the old 20k pro is slick slick slick, great size. I miss it dearly. It's been on some best battery lists & you can still get some on eBay on & off, but it feels like no battery has been as well proportioned since. It also had something that seems so weird toe that doesn't exist elsewhere: you could put it into a mode where it was also a USB hub with the usb-c device being a host to the two usb-a ports. The usb-a ports only got the 0.9a in that mode, no quick-charge or whatever, but usb-c still got full power & the ports were powered. The idea of a USB charger that also acts as a data hub seems drop dead obvious, and I largely suspect there was some kind of wild IP hijinx/conspiracy that blasted the ZMI 20k out of existence for being so rad. Thanks for the suggestion! Go ZMI.
CommieBobDole 3y ago
Yep, there's a comment at the bottom in which the author admits that, after further testing, it doesn't actually work.
johnklos 3y ago
You're absolutely right about that - power banks that don't have that momentary cutoff are rare and would be highly sought. However, vermaden is powering a small form factor computer that appears to be able to take anywhere from 12 to 19 volts. This means the power is internally regulated, which means that there's at least some amount of capacitance in the regulation circuit. Many devices like these can handle a drop of power of a small fraction of a second, but likely not more. For my own SBCs, a rather large capacitor made a power bank I was using work, but the size of the capacitor was unwieldy. I'm more inclined to use an all-in-one charging and battery circuit that feeds the SBC directly. I'm surprised there isn't already a market for power banks without momentary cutoff. There's quite a market for UPS Pi hats already.
- sidewndr46 3y ago
  The power bank in question also costs $100 new, which is more than the cost of a UPS and buying a replacement battery
JackeJR 3y ago
The chargers that drop connection is typically because their max power budget per port depends on how many ports are used. E.g if my max power budget is 200w and I have 2 usb c pd and 2 usb A. Each usb c pd can have a max of 100w per pd3.0 specs. So if I have 2 devices plugged in to both usb c, if I need to plug a USB A device in, I need to lower at least one of the usb C to 65W.
- jauntywundrkind 3y ago
  Even if my phone is charging & I plug in a Bluetooth headset, the Ugreen Nexode will drop & reconnect. I think the OTAO might even allow oversubscribing, where if my monitor or laptop are only using 1/2 what they're negotiated for, it'll let another device join for some addition more. Then only drop a device & reconnect after it actually goes over 200w. Seems weird but I love the boldness. There's so many USB trigger board systems where the ask isn't right sized, where a device just asks for 3A or 5A but ends up using far less. To me it's a courtesy to look back a bit & decide you can oversubscribe the new guy, and reconnect someone latter... maybe disurptive then. But compared to reconnecting everyone immediately, which is disruptive? Love it.
  - JackeJR 3y ago
    I have seen chargers that simplify the logic to drop everytime a new device is connected or disconnected to recalculate the max power per port. So these days if I am shopping for a charger say for a IP cam, I assume that each usb C takes 100w and usb A to take 22.5w and calculate what the max draw could be. If the max advertise power budget is at or above this value, then it is a fairly good indication that there will not be any dropping of connection.

vermaden 3y ago

That is true and I must sadly admit that I did not tested that ... after some more research I have found that ZMI QB826G 25000mAh powerbank has that 'ups' feature. I have already ordered one and I will test with that one. I also need to add some notice to the article that my first approach failed. Regards, vermaden

jauntywundrkind 3y ago
I just tried with my pre-ordered indiegogo "No. 20", which is the QB826 (no G). I haven't tried with a laptop yet, but my phone indeed kept steady power in to it when I connected/removed a charger from the power bank! Neat!! Indeed seems like some level of ups capability! Confusing naming, but I had & adore ZMI's earlier "20k" power pack. The new No. 20 is 25Ah/2 usb-c/210w, the old 20k Pro is 20Ah/1 usb-c/65w(+ 2 decent usb-a)... But damn the old 20k pro is slick slick slick, great size. I miss it dearly. It's been on some best battery lists & you can still get some on eBay on & off, but it feels like no battery has been as well proportioned since. It also had something that seems so weird toe that doesn't exist elsewhere: you could put it into a mode where it was also a USB hub with the usb-c device being a host to the two usb-a ports. The usb-a ports only got the 0.9a in that mode, no quick-charge or whatever, but usb-c still got full power & the ports were powered. The idea of a USB charger that also acts as a data hub seems drop dead obvious, and I largely suspect there was some kind of wild IP hijinx/conspiracy that blasted the ZMI 20k out of existence for being so rad. Thanks for the suggestion! Go ZMI.

CommieBobDole 3y ago

Yep, there's a comment at the bottom in which the author admits that, after further testing, it doesn't actually work.

johnklos 3y ago

You're absolutely right about that - power banks that don't have that momentary cutoff are rare and would be highly sought. However, vermaden is powering a small form factor computer that appears to be able to take anywhere from 12 to 19 volts. This means the power is internally regulated, which means that there's at least some amount of capacitance in the regulation circuit. Many devices like these can handle a drop of power of a small fraction of a second, but likely not more. For my own SBCs, a rather large capacitor made a power bank I was using work, but the size of the capacitor was unwieldy. I'm more inclined to use an all-in-one charging and battery circuit that feeds the SBC directly. I'm surprised there isn't already a market for power banks without momentary cutoff. There's quite a market for UPS Pi hats already.

sidewndr46 3y ago
The power bank in question also costs $100 new, which is more than the cost of a UPS and buying a replacement battery

JackeJR 3y ago

The chargers that drop connection is typically because their max power budget per port depends on how many ports are used. E.g if my max power budget is 200w and I have 2 usb c pd and 2 usb A. Each usb c pd can have a max of 100w per pd3.0 specs. So if I have 2 devices plugged in to both usb c, if I need to plug a USB A device in, I need to lower at least one of the usb C to 65W.

jauntywundrkind 3y ago
Even if my phone is charging & I plug in a Bluetooth headset, the Ugreen Nexode will drop & reconnect. I think the OTAO might even allow oversubscribing, where if my monitor or laptop are only using 1/2 what they're negotiated for, it'll let another device join for some addition more. Then only drop a device & reconnect after it actually goes over 200w. Seems weird but I love the boldness. There's so many USB trigger board systems where the ask isn't right sized, where a device just asks for 3A or 5A but ends up using far less. To me it's a courtesy to look back a bit & decide you can oversubscribe the new guy, and reconnect someone latter... maybe disurptive then. But compared to reconnecting everyone immediately, which is disruptive? Love it.
- JackeJR 3y ago
  I have seen chargers that simplify the logic to drop everytime a new device is connected or disconnected to recalculate the max power per port. So these days if I am shopping for a charger say for a IP cam, I assume that each usb C takes 100w and usb A to take 22.5w and calculate what the max draw could be. If the max advertise power budget is at or above this value, then it is a fairly good indication that there will not be any dropping of connection.