Re: Power inverter question
If i get a small power inverter like a 225 watt to one ac plug how long can i expect a 12 volt battery to provide power to something like a light or even a radio.
on a 100 watt light bulb, you will get roughly 5 hours on a decent size 50 amp hour deep cycle battery.
Take your rated device wattage, divide by 12.8, multiply by 1.2 (for inverter inefficiencies). Divide your battery capacity by that.
50/(100/12.8*1.2) = 5.3 hours
Also, the faster you draw down a battery, the less capacity it has. Batteries get their amp hour rating by either drawing it down at 1 amp and then rating how many hours, or sometimes even .5 amp. If you are drawing 50 amps, there isn't a snowballs chance a 50 amp-hour battery will last 1 hour.
*disclaimer... inverter efficiency is all over the place, a cheap walmart 225 inverter might be around 80%, give or take. (my 1.2 multiplier) Efficiency also changes with load. (too little or too much makes an inverter inefficient).
