(Continued from Part 1.)
DETERMINING HOW LONG A PPS CAN SUPPLY POWER
To determine how long a fully-charged PPS will last, three things must be considered:
1.) The wattage of the device being powered
2.) How long you need it to run for, and
3.) The wattage capacity of the PPS battery.
As previously mentioned, to simplify the math some of the battery rules are ignored such as maximum drawdown percentage of a battery and the energy loss when inverting from 12 Volts DC to 120 Volts AC.
Appliance Wattage – Nearly every 120 VAC electric device has the wattage stamped on the bottom or labeled elsewhere. An average LED light bulb in your home uses 6 watts. A typical box fan is 100 watts, a coffee-bean grinder 130 watts, a soldering pen 350 watts, a food processor 400 watts, a blender 600 watts, and a rice cooker uses 700 watts. The higher the wattage, the more electricity the device uses and the faster that it will draw down the battery.
Run Time – A device may have a high wattage but won’t drain the battery much if it’s only for a short period of time. Things like coffee grinders, food processors, and blenders won’t draw the battery down significantly since they’re only on for a few minutes each time that they’re used. Ditto for things such as a drill press or a jigsaw doing a small job. A 700-watt rice cooker on the other hand, is on for 30 minutes at a time and will be a significant drain on the battery. And the heavy resistive loadof a 1,500-watt space heater will drain it in no time.Continue reading“Post-SHTF Lighting: Portable Power Stations – Part 2, by St. Funogas”
