Additional Wallmounted Solar Batteries (and Maybe Failover Mechanism)

My thought was - why not make a solar panel with an integrated battery pack and micro usb output so that we can supplement our Eufy Cams?

It would be even better if somehow we could have a pair of solar panel batteries so that after one is completely drained, it would start drawing power from the second solar panel battery, thereby allowing the first solar panel battery to completely recharge itself. (And once the second solar panel battery is drained, it would failover back to the first solar panel battery).

The failover scenario would be especially helpful for situations where a solar panel may only get something like 1 hour of sunlight per day - so over the course of several days, the integrated battery could fully recharge itself while its pair is handling the camera load.