I wanna get a solar panel to charge or 2 car batteries. Then connect the battery to a 800watt power inverter so that I can power a tv. Will the 8watt solar panel charge my batteries and around in how long?I just wanna use the panel to charge the batteries, no to use the panel directly with my electronics. Thanks for your answer and help me with that.
8w will be .5 amps or so.That would charge a .5 amp battery in an hour.scale that up to whatever your battery amp-age is and you will have an idea.But given that car power is upwards of 40 amp/hour,your looking at 60 hours+ for a full charge on small battery.I run a 400w inverter for emergency lights and tv (get the occasional power cuts)from an old truck battery with big amps and charge it with an optimate,but in doing so I found that I had to run a amp check on power draw to find the lowest use lights.and tv,Some of the so called low power consumption compact fluorecents had widely variable draws,after testing one was found that drew .68 amp and I chose the lowest mesured tv amperage draw.not exactly an answer to your qu,but end use is the same.Running the lamp only I eventually gave up checking on the drain after about 30 hours and now just periodicaly charge the battery.Rounding off.tv draw maybe 3 amps for a small set and watched for say 6 hours would be 8 amps drawn.that would need -2 hours on your proposed set up in ideal conditions.I have kept the figures rough because there is always losses in any system .so it comes down to how much tv you watch and how much the sun shines
welcome to the wonderfull world of solar! you probably have a 2Vdc 8 Watt solar panel, to figure out its charging amps capability we do this equation Watts/Volts=Amps 8watts/2Vdc=.5Amps this is a conservative figure, since solar panel ratings are calculated using winter time sunlight, sunny locations and more daytime hours will give you higher amps. a typical good condition car battery is rated at 40Ah (Amp hours).to find out the charge time, we use the following formula; Amp Hours/Amps=T where T is time in hours 40Ah/.5A=26hours this is charge for a single battery, two batteries will double to over 52 hours. lets compare to charging a battery with your car, a car alternator puts out about 60 amps but usually run about half capacity. 40Ah/30amps=.3Hours! An alternator is far more efficient so charging with a small solar panel is best as an alternative or for low power applications. As far as using an inverter to power a TV, we can calculate how long the battery will last by using the original formula. a typical 9tv will use 70 watts 70watts/2Vdc=5.8A 40Ah/5.8A=6.9hours this figure is by drawing all the power from the battery, voltage inverters have a safety feature that will not let you discharge your battery all the way, so 40Ah battery will power a 9 tv for about 4.5 to 5 hours.
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