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Comment by klyrs | Hacker News Reader

My solution is a usb- chargable backup battery.

Might want to check whether the battery includes a hub. I was surprised to find that my Dell power bank does, which is great because I can get photos off my phone while I charge both the phone and my laptop, but would negate any protection in this scenario.

Thanks for the heads-up! Happily, my battery doesn't have that feature.

Is it possible for the usb powerbank to carry a virus? It might not be as safe as you hope. Of course it shouldn't accept any data, but considering how poorly ports and devices are often secured, I bet that quite a lot of them do accept data.

But why do USB devices even accept unauthorised data at all? There's probably a good reason for it that I don't understand, but it seems to me it's rather obvious that blindly accepting data from unknown devices is quite a big security risk. And yet I keep seeing these new data port standards (USB, thunderbolt, etc) that just blindly trust whatever gets connected to it, and allow it unreasonable control over the device. I guess the reason is that you want to be able to plug a new keyboard into your PC and have it just work.

Because having physical access to a device is not "unauthorized". It's like asking why does the body automatically get every virus and bacteria from every surface that you lick, "it should be more thoroughly checked"...

Or maybe the user just shouldn't give physical access to devices that are not trusted.

But physical access is everywhere, as these charging points show. And a USB drive is really easy to hide and stick into anything. Automatically trusting something that's super common and easily compromised is a really bad idea.

Your argument, in case of computing devices (which means with well-defined physical connectors, as opposed to wetware), boils down to "just because." Android and iOS used to ask for permission, a long time ago - but it was dropped as "not user friendly". So, the problem is not "impossible to do", merely "inconvenient w/r/t other goals".

As for not giving physical access...easier said than done. Looking around, I see multiple such devices lying around here, with the owner within 20 m, but not paying attention. IMNSHO asking for authorization is far more logical than assuming "whoever can get their hands on it is authorized."

That's good. Plug in the battery at the station, "here, jack this." Plug your phone into the output jack of the battery.

They usually say not to charge the battery and draw from it at the same time. They never say why.

So, get two batteries, and charge one while using the other to charge. Plus, you then have a charged backup battery...

Follow the money: a system which only works in one mode or the other at a time is an order of magnitude easier to design/debug/manufacture than a system that needs to work in one mode, other mode, both at the same time, and seamlessly switch between these (=> also cheaper).

Passthrough creates a lot more heat, and that heat hangs around longer, which is not good for the battery. I think Anker said that.

To dissuade you from charging the battery from the battery itself.

The charge controller doesn't allow simultaneous charge and discharge. It might allow simultaneous charge and power. The concern is, if your power pack does let you power devices while charging the battery, it's passing the power straight through from the wall, not via the battery. Is it also passing the data lines straight through? Not sure, you'd have to check the schematics. Here's an example... a great board, I own one, but I have no idea if the data lines are isolated: https://www.adafruit.com/product/2465

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