[Marcella]

“My brother currently works for a security company has the contracts to replace some of those batteries that are backing up most of those cell phone towers,”

You can tell your brother they don't work after a hurricane takes out power. No cell phone works and people don't understand why my house phone still works - it's because that one plugs directly into the wall. My son called me from England after Ike came through and my house phone plugged into the wall worked. No cell phone worked.

I don't plug in the charger to the solar panel unless I'm recharging batteries so the greater part of the time the solar panel has nothing attached to it, no reason to have the charger plugged in. An EMP from a nuclear blast “might” damage it if the charger was attached and batteries in the charger, but an EMP from the sun would not harm it as the charge goes directly into the grid and not into anything outside the grid.

You believe whatever you want and I'll believe the scientists who did the tests and have the knowledge to differentiate between the types of incoming EMPs.

[Yosemitest]

Those "landline" phones will only work as long as they have power.
When the batteries run out of power, normally a major junction box or "hub" that belongs to the phone company, they no longer have power to "boost the currency' coming from the phone company's home station, where it either receives its power from the power company, (and is backed up by a generator (normally LPG or some other fuel).
Once that power is no longer received, the phone lines go dead, until power is restored. I disagree about solar panels. When the EMP "charge" crosses the photocell while it's active or charging, it overloads it and damages it. (Again, proven at Kwajalein Atoll, years ago. My brother was there.)