A:Answer Depends on the current state of charge of your battery. By the way, 20,000 mA (milli amps) is 20 Amps. If you have a small phone charger that can output 1Amp, from a completely flat battery, that will be a little over 20 hours to charger. Even if you recharged overnight, you will need to sleep like Rip Van Winkle for a full charge. Or you can just be sure to give yourself plenty of charging time each night during the week before you go off grid.
