My need for my new Beryl AX is a somewhat unusual set of circumstances. I enjoy scuba diving in cold uk waters, the boats from which we dive and sleep are converted fishing vessels many not replete with the conveniences of modern life. One boat in particular does not run the alternator to power the electrical sockets unless absolutely necessary (my wifi is not deemed vital). So what I need is a system that keeps my router powered at all times, from wall power when available. Internet access will be provided by a little mobile hotspot plugged into the router via usb. The hotspot has a battery and receives charge from the router. What I was thinking is to get a USB powerbank with pass through charging (ability to provide power while at the some time charge itself from wall power when available). The router will be hooked up to the battery bank and hopefully be able to run all day long regardless of wall power state (usually we would have wall power from around 5pm to 7am). Would this set up work? Or is there an easier solution I’m not seeing?
Many thanks.
Yes, it can work. You would need a power bank with a USB 5V/3A (15W) output. A 30,000 mAh capacity should get you over 10 hours of use with the Beryl AX.
To build off @RBzee 's comment: if you have the budget, I’d look for one of the ‘luggable’ power banks people use for camping that also feature a NEMA-15R receptacle. It sounds like the last thing you’d want is to be caught without being able to power some odd device that only has a ‘wall wart.’
AndroidCentral’s Best portable high-capacity power banks, including 50,000mAh+ chargers 2023 article should give 'ya some ideas. Some support solar charging, too (eg: Jackery Explorer 300 Portable Power Station).
I used the Jackery Explorer 300 at work (not mine). It’s pricey, but works great.
Ya ever heard the ol’military saying “Two is one & one is none”? Every one/company should have a ‘cold spare’ … or two. Then see if yer boss will let 'ya mark a portion of your paycheck to purchase over periodic deductions against one of 'em.
Most tech is a near immed. write off/deductible @ tax time, anyways. YMMV. 
Thanks for the replies, so tried it out at home with a battery pack I had lying around and found I could just about manage it with a 20,000mWh battery. So bought one that said it supported pass through charging. It can power the router just fine (even with two hotspots charging and plugged in via usb to the router) but alas the passthrough charging was a flop I need to play around a bit more but there seemed to be intermittent cut offs to the output ports while charging. But no big deal I’ll just have to juggle the power sources twice a day.
As to two is one and one is none, well again the skipper has the alternator if it becomes an emergency (it won’t) and in diving we have another saying ‘plan for two failures, if you have to plan for more than two your system is the failure.’