How I Size Solar Battery Bank and Solar Panels – How Many Batteries? How Many Solar Panels?

How I Size Solar Battery Bank and Solar Panels - How Many Batteries? How Many Solar Panels?

Now we know how much load we will have on a typical day being drawn from our solar batteries its time to determine how large of a battery bank we need. the loads are measured in watts while the batteries are measured in amp hours. once you determine if you will go with a 12v or 24v or even a 48v battery bank system its time to figure out how many amps you will need.
match the watts use in a day with the watts in your solar panels however you must consider storms, seasons, bad solar days so having more solar is good.

20 Comments on “How I Size Solar Battery Bank and Solar Panels – How Many Batteries? How Many Solar Panels?”

  1. Very simplistic description of battery technology which if you follow will cost you money. There is no reason to cycle a deep cycle battery only 10-25%. Standard is 50%. And no you will no kill your battery cycles if you do 51%. That's just not accurate. You can cycle more than that occasionally if you have to. Try not to but still, will not kill them.
    Also, efficiency in wire sizes only matter if you don't size them correctly. You can go 12 volt all the way with this system, BUT you will be using big assed wires. The efficency will be the same. One more thing, it will be very costly to plan your system piece meal like this. You would want to account for ALL power sources. Putting off wind, in favor of a larger battery bank, is not saving you money. Batteries are expensive. So plan for all. If you have enough wind, use that too. And I would plan for 4 days of battery capacity and use alternate energy sources like a generator, DC generator, or wind to make up the difference. Also remember you will need more capacity in watts due to losses than your daily needs. Plus you have to put that power you use when the sun isn't shining back into the batteries. This will require more watts than you used due to inefficiencies in battery technology.

  2. Dude….telling people they need x number of watts, volts or amps, is all well and fine. BUT…how many friggin batteries is that? You totally skipped past that by saying you needed 964amps or whatever. That means NOTHING to the layman. You evidently think that EVERYBODY knows how many batteries it takes to provide 964 amps. Then you move on the the panels, but how many batteries do you need? The name of the video states, how many batteries? I just wasted like 15 min of my life hoping to learn something, and you didnt even explain the most important part. I can have a thousand panels and need 967 million amps…but HOW MANY BATTERIES is that??

  3. Steve Robertson youtube channel is also good at describing solar set ups…
    Where i live i picked up some of the panels i will use for $.48 a watt…(12- 24 volt 255 watt)
    Any way Steves attitude is revolve your life around the sun…
    Run larger arrays and use controller charger/ inverter
    (In Steves case a 2- Pip4048 )
    So his large usage is while the sun is up….
    So he gets away with a small battery bank because at night he keeps the load small..
    ( lights, computers, etc)
    On another channel
    An easy way to adjust panels for up and down pitch..
    And east to west…
    Set a plastic cup large side down..
    On your panels…
    And adjust until the shadow is gone… Or even….
    Thanks Jeff for showing us your system and calculations..

  4. Very informative vide and well presented.  On those cloudy days when the system is tapped, I would strongly consider a gas generator as a backup to the solar system just to carry me until sunshine returns.  At least I would be able to run some lights and keep the fridge going and not lose any food.

  5. You, know you did a very clear and simple explanation on your video. I'm a 35 year electrician and even I couldn't explain it that simple. The one thing I think you could have covered would have been the input side of things, for example for every amp you draw from your battery bank you need roughly 1.5 amps to push back into bank. But you can't really exceed no more than 10 to 15% of your total battery capacity. Any higher you run the risk of damage to the bank. So all the extra solar panels will not really help, unless you have a cloudy days were your system will still produce something. The better chargers out there will not exceed the 10% but will divert the extra for maybe a heater or hot water. Just a extra input sorry

  6. Here are the benefits of a 12v system
    Pros
    you can charge it with your car if needed in a couple hours.
    You can use a cheap mod wave invertor if you sine wave inverter goes out.
    Cons
    I'm told you need higher volts to run longer distance
    Hard to find sine wave invertors for heavy loads (above 2k)
    Hard to find investors that hook into a house fuse box.

    Those are a few I could think of. I have 12v and a 24v systems. The maximum distance from panels to bank is 30 foot. I haven't noticed a difference in either system. The only sine wave I have is for my 24v system. I wish I would have gone with a 12v, but who knows if I would have gone that way I may think the oposite. Problem is somethings like washer machine, freezer, won't work with mod wave.
    IMO you should try to have 10x battery bank as solar panels. Currently I'm at 5x. I haven't had problems, but fear my batteries won't last as long. I'm at 2 year now running this way, with my 24v system. My 12v I ran the first year on car batteries, and for the past 2 years have ran on a old deep cell I got In A vehicle I bought. (Previous owner had it as the trucks battery) I keep it as a reserve system and use it for off hand things. Like when I get water to pump from haul tank to storage tank. Or other things I don't use everyday.
    Hope my insight helps

  7. Higher the voltage, smaller the cable. With higher voltages, you can get the same amount of Watts with fewer Amps. Watts = Volts x Amps (P=VxI) A big expense in an off grid system is cabling. Keep your panels close to your inverter and run AC current as much as you can. Short DC runs, Long AC runs. You will save a lot of money if you keep this in mind.

  8. for a regular house looks like you use small power, I use in average 18000, this is almost 3 times, I have all my appliances energy start.

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