Portable solar panels are a little different than fixed rigid solar panels. A thorough discussion on portable panels is here.
The rigid aluminum frame panels are just the solar cells wired in series and are brought out to a set of terminals on the back of the panel as shown below
Some modern inverter panels are wired like the one below.
Portable solar panels could be semi flexible (fold up) or flexible enough to roll up. These panels usually have a 5 volt regulator and from one to three 5 volt USB sockets for charging radios, lights, cellphones, or battery chargers. Depending upon the size of the panel they can provide up to 2 amps at 5 volts. Higher power panels also have a round power coaxial connector that provides from 12 to 17 volts out to go to a charge controller to maintain a 12 volt rechargeable battery shown below. Under full load the voltage will drop to around 12 volts. With a small load the voltage could rise as much as 17 volts.
The problem lies with an EMP strike destroying the charge controller rendering it useless. The 5 volt charge controller is a little board with a handful of parts that maintain a continuous 5 volt output in various sunlight conditions. It is shown below.
If an EMP hits, the chip or regulator on the controller will have to be replaced by a competent technician. Once it is repaired it will perform just as new.
As a work around, you could use one of those cheap auto cigarette lighter USB chargers and a cigarette lighter receptacle as shown below.
A coaxial power connector attached to the pigtail of the adapter is plugged into remaining 12 volt coaxial socket on the panel and you will have your 5 volt source available again. Of course your cigarette lighter USB charger along with spares should be kept in hardened Faraday container.
If you or you know someone that's tech savvy you can just replace the buck chip and Schottky diode and you should be able to restore the USB buck regulator system. Keep many spares on hand. Below is a typical schematic of the 12 volt to 5 volt USB adapter.
©2022 Rick C. Ver 0.12 April 4, 2022