How do you figure the amount needed watts of solar panel and the number of 12 volt batteries you need ?
I am moving to area with no electricity and trying to figure out what wattage of solar panel I need and how many batteries will it charge?
Is it feesible to run a small fridge on solar panels?
Add up all your electrical loads in watts. For example, say 100 watts.
Calculate how many hours of direct sun you will get per day, on average, worse case. For example 8.
Decide on how many hours the batteries need to supply power if the sun is not out, eg, on cloudy days, or several cloudy days. For example 24 hours.
Since you only have sun 1/3 of the day, you need 100 watts x3 or 300 watts of solar power.
But you need more to charge the batteries for cloudy days, so double that to 600 watts.
A large lead acid battery will store 1kW-hr of energy, or enough for 100 watts for 10 hours. Since our example has stored power for 24 hours, that is 2.4 batteries, say 3 batteries.
so bottom line, you need
1. a 600 watt solar panel ($4000)
2. 3 marine lead acid batteries, each 100 amp-hour, about $900
3. A charge controller $400
4. An inverter to convert 12 volts DC to 120/240 volts 1000w $300
.
Add up all your electrical loads in watts. For example, say 100 watts.
Calculate how many hours of direct sun you will get per day, on average, worse case. For example 8.
Decide on how many hours the batteries need to supply power if the sun is not out, eg, on cloudy days, or several cloudy days. For example 24 hours.
Since you only have sun 1/3 of the day, you need 100 watts x3 or 300 watts of solar power.
But you need more to charge the batteries for cloudy days, so double that to 600 watts.
A large lead acid battery will store 1kW-hr of energy, or enough for 100 watts for 10 hours. Since our example has stored power for 24 hours, that is 2.4 batteries, say 3 batteries.
so bottom line, you need
1. a 600 watt solar panel ($4000)
2. 3 marine lead acid batteries, each 100 amp-hour, about $900
3. A charge controller $400
4. An inverter to convert 12 volts DC to 120/240 volts 1000w $300
.
References :
What you need depends largely on where your house or cabin is, and how much electricity you will be using.
If you use something like a Sunfrost chest freezer (very expensive) converted to a refrigerator, that may use 1/3 kWh per day.
Generally you do not want to discharge a battery bank below 80% (50% for some types), so let’s say you need 1.5 kWh of battery. This doesn’t count any other loads you might want to put on it. Pretty much forget about a washer or dryer, but you could have a lighting, a laptop, music, etc.
How much panel you need to keep this kind of bank charged depends on where you are. In Arizona, 400 watts of panel may be enough – costing $1600 or so. If you’re further north, or in a valley or cloudy area, you’ll need more panels.
Bear in mind that an inefficient refrigerator (like a cheap dorm refrigerator) can use 30 times that energy.
References :