A real emergency today is loss of services we never expect to be without. Electricity, water, heat, cooling, communications, and of course food. The Northeast United States has experienced hurricane and winter storm emergencies that crippled essential services, electricity, water, heat, cooling, and of course food availability.
The hurricane Katrina mess with be with us as an example of real civil strife, with none of the services mentioned above. Communications by any means today is Wireless devices. Cellular, smart phone, Internet, all may not be available during civil strife and loss of services. Hopefully, one has Neighbored-Up and Radioed-Up in advance.
A couple of bucks investment - - - Next time you car needs a new battery, don't trade in the old one. Pay the core charge and keep the old one somewhere. Even through the battery won't serve in the car it will have energy for re-charging Neighborhood Watch Radios or cell phones for a long time.
Communication device charging utilizes DC voltage regulation from an AC source such as wall charging device or a DC source from USB computer port. The GMRS radios utilized for Neighborhood Watch Radio usually have a drop in charger with an AC wall plug charger as the DC power source. The resulting DC voltage to the drop in charger is five to twelve volts DC.
An old car, lawnmower, or boat battery with inadequate voltage for its original purpose will usually charge a communications device many times. Cut and strip the wires, attach to battery terminals with any method, even metal or plastic ties. Don't worry about polarity; if it lights up, its correct.