Joshua asked in EnvironmentGreen Living · 4 months ago

What size solar panel do I need?

I have a power adapter that needs consistent standard us outlet power. The setup I want is a solar panel that charges a battery and an inverter to convert that battery to a standard is outlet. I need a solar panel that can power the power the inverter and change the battery and when there is no power (sun) coming from the solar panel the battery is used to provide power to the inverter  the power to the inverter needs to run 24/7 so the question is. How big of a solar panel is needed as well as how big of a battery is needed?

7 Answers

  • 2 months ago

    sorry but not sure wat u mean by power adapter. we would hav to no how much power that power adapter uses. if i was at home jus an example for one person so i dont use that much energy id get four 400w solar panels. the one i hav is huge its 6ft 7in long 3ft 3 1/2in wide. i start out with four 12v 100ah batteries conect 2 in series to get 24v then the other 2 also then conect those 2 bundles in paralel. if thats not enough jus add more bateries

  • 4 months ago

    The panel should supply the same wattage supplied by the adopter, do the math

  • Anonymous
    4 months ago

    2cm x 2cm.             . 

  • 4 months ago

    Hey Joshua, the short answer is don't bother.  I could get into all the numbers and calculations on how much panel is needed to run a continuous 250 watt load plus the inverter losses.  The point is this, a continuous load that size adds up to 6 kwh of power each day, which is more than our entire home uses.  There is a reason these places are making and selling cryptocurrency mining machines instead of just plugging them in at their own home, they don't pay for the energy they use.  Producing it with solar power doesn't work for the money it generates either, or they would simply keep the machines

    We've been running our home on solar and wind for 18 years, it doesn't save us much money, but if it did make financial sense to run a miner on solar, it would make financial sense to run your entire home on solar as well, have you done that yet?  Take care Joshua, Rudydoo

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  • 4 months ago

    Completely depends on how much energy you want to pull out of the system to run things. To run a few LED lights, a small 5 watt panel maybe 2 square feet would be fine. To run a house with AC and heat and appliances, you might need a few hundred square feet of panels and a few $100,000 of batteries.

  • Mmm J
    Lv 7
    4 months ago

    You want a solar generator. PLAN, PLAN, PLAN.

    My opinion on what you want (and why):

    Four 100 amp hour, 12 volt, LiFePo batteries (connected in parallel - this keeps the power at 12 volts; 400 amp hours). If 4 is too much, start at 1 or two and grow to 4. The reason you don't want lead acid is because those batteries can be damaged if you regularly get the power storage level below 50% of capacity. With LiFePO batteries, you can use more than 95% of the capacity without impacting the battery life. LiFePO batteries are expensive, though... Don't use a car battery. If you have to go lead acid, get a SEALED AGW deep cycle battery. I used to use them - they are about 65 pounds each (the 100 ah LiFePO battery is about 25 pounds). There are several more advantages to using the LiFePo batteries and while they cost about 6x more than the lead acid batteries, they have been well worth it.

    Two "side terminal battery terminal" posts.

    One 800 watt pure sine wave power inverter. For sensitive electronics, pure sine wave is LOTS better for the equipment than modified sine wave.

    Between 200 watts and 400 watts of solar panels. The dependency is how many panels need to be recharged - and how quickly the recharge needs to happen.

    One stand-alone 200 watt fuse/breaker (between the + terminals on the battery and power inverter).

    One 40 amp MPPT solar controller. This connects the solar panels to the battery.

    You'll need various lengths of 1/0 or 2/0 gauge cables for the 120 volt side of the connection (battery to power inverter). The size of the lugs will depend on the terminal connections on the inverter, battery and breaker/fuse.

    One roll of black 14 gauge stranded, jacketed cable.

    One roll of red 14 gauge stranded, jacketed cable.

    These will be used for low power connections to connect a power meter/battery monitor and to connect the solar controller to the battery.

    I'm working on my fifth solar generator right now. It is designed to power our refrigerator in case there is a commercial power outage. 2 LiFePO batteries, and a 2200 watt pure sine wave inverter; 40 amp MPPT solar controller.

    Everything (except the solar panels and their cables) are installed in a rolling tool box from Home Depot.

    The solar panels, solar controller, solar panel cables, battery monitor and LiFePO batteries are from Renogy (via amazon).

    The side battery terminal posts, high power cables and low power cables are from a local auto parts store - and available on amazon if you want "fancy" cables (different sized lugs on each end, pretty braided copper in the sheath, etc.).

    Series 27 battery trays help stabilize the batteries (my set up needs to be "portable", hence the rolling toolbox).

    The power breaker/fuse was purchased through amazon. They may be available at a local boat parts store.

    The rolling toolkit also has a few "soffit vents" installed for ventilation (cooling). 3 inch, 2 inch and 1 inch plastic soffit vents are available from amazon. I already had appropriate sizes of hole saws and silicon adhesive/sealer. The inverter can generate a lot of heat when it is working. They typically have built-in fans, but mounting in the toolbox without vents can be an issue.

    I had some wood scraps from a shelf we no longer used in the house that were installed inside the rolling tool case to securely mount the inverter, battery trays, solar controller and battery monitor. a bunch of 1 inch carriage bolts with washers and nuts. A bunch of 1/2 inch screws. Local hardware stores...

    There are lots of tutorials at YouTube. The above 200 ah LiFePO system currently under construction will total out at about $2,000.

    My fourth single 100 ah LiFePo batter system power my laptop + four 21 inch monitors, 2 external drives, a 27" iMac, cable modem, gigabit network switch and a few other things. It draws around 230 watts when everything is running. I need it only to run for about 6 hours/day. There is also a computer UPS between my electronics and the solar generator that can keep everything up for about 3 hours so the solar generator is actually only connected to the computer battery back up - that UPS provides the power distribution to the computers, monitors and network equipment...

    BE CAREFUL. These batteries may "only" be 12 volt, but the are *very high amperage". Remember, they can supply enough power for the inverter to power the computers or appliances. SAFETY FIRST.

    An alternative is to have someone else source the parts and build this for you. Check

  • 4 months ago

    In order to answer you question, you have to know how much power you plan to draw from the battery.  Are you going to power a laptop, or light up a whole house and power appliances? Once you know your power needs, you can design a battery/inverter/charge controller/solar panel scale. 

    After you do this, and know your solar window(the sun's power at your location), you properly size a basic system.  Another thing, what happens if its cloudy during the daytime.  Well then you may need to upsize your system to handle multiple days so that you don't discharge you battery bank too far.  If you draw too much, you may need to get a generator to top up your battery bank during a stretch of cloudy days.  Its a lot to think about.  See Home Power magazine for examples of systems. 

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