Who wants to know how many batteries can a 200 watt solar panel charge?. A solar panel will charge an unlimited number of batteries without a load. The load being an electrical appliance for instance. But how many batteries will a 200w solar panel charge efficiently and in the quickest possible time?
I suspect you are asking this question because you have 2 or more leisure batteries in your vehicle. Am I right? Or is it because you have a 200 watt panel and want to know how many batteries it will charge? Or is your question related to portable power stations? Whatever it is, I will attempt to answer it here. By the way, if I don’t manage to answer your question. You can always leave a comment at the end of this post. Because I can always answer it later.
Quick Jump Menu
How Many Batteries Can A 200 Watt Solar Panel Charge?
“The answer is one to charge a 12v 100Ah leisure battery from 0 to 100%. I know you thought it would be at least two, didn’t you? The minimum wattage solar panel you should use to charge a 12V 100Ah leisure battery is 150 watts. And this is assuming there is 8 hours of continuous sunshine per day. This is based on this theoretical calculation;”
Battery amp hours (Ah) multiplied by volts (V) equals Watt Hours (Wh). Then watt hours (Wh) divided by sun hours (H) equals solar panel wattage;
100Ah x 12V = 1200Wh
1200Wh divided by 8H = 150 Watts
But because in the real world you should overestimate the number of watts required by 20%.180 watts would provide the ideal performance.
A 200 watt solar panel will charge 2 batteries but it will take longer. But for strictly best performance it is one. So If you have 2 leisure batteries in your vehicle. To achieve the very best performance you will need 2 x 200 watt solar panels.
In case you didn’t know according to Redarc Electronics
Watt’s are named after the Scottish inventor James Watt and is a basic unit of power. The formula to describe a watt is; Power = Voltage x Current, so Watts = Volts x Amps
Volts are a unit of electromotive force, the volt measures how much “potential” there is in an electric circuit. The higher the voltage, the more electrical current will flow in the circuit.
Amperes (or Amps), is the measure of electric current. One Amp is equal to a number of electrons passing a point in a circuit each second at a certain voltage.
Amp Hours (Ah)
Amp hours is a measure of stored power. Amp hours is the number of Amps drawn, for the amount of time in hours that you draw that current. Amps x hours = Ah (Source: Redarc Electronics Australia)
Watt Hours (Wh) according to WhatIs.com
The watt-hour (symbolized Wh) is a unit of energy equivalent to one watt (1 W) of power expended for one hour (1 h) of time. The watt-hour is not a standard unit in any formal system, but it is commonly used in electrical applications (Source:WhatIs.com)
My Answer Is Too Over Simplistic
As I mentioned earlier you can use a 200 watt solar panel to charge two leisure batteries. This is because how likely would you allow your batteries to deplete to zero percent. So for instance. A 200 watt portable solar panel would keep your leisure batteries topped up. Provided you had a good amount of sun each day. Ok, you may have to run the generator now and again. If your battery charge percentage became dangerously low.
So if you are thinking about installing a single 200w solar panel to your recreational vehicle, trailer/caravan, or boat. It would be better if you hooked it up to a vehicle with only one battery. The formula I gave you above is a theoretical formula. In the real world, things don’t always work exactly as the theory. You have to take other factors into consideration.
What do I need to take into consideration when charging batteries with a 200 watt solar panel?
There are several factors you need to take into consideration when charging batteries with a 200 watt solar panel. This is because the formula suggests that 200 watts is too much for one battery. This is not the case and I do not want you to think the panel will overachieve. Because it won’t.
Everything depends on your location in relation to the sun. Are you using an installed or portable solar panel? Is it summertime or wintertime or between seasons?. Is it full sun, partly cloudy or cloudy?. You might not know that you will not achieve the full output of 200 watts from the solar panel. Or the batteries are not 100% efficient during charging because they suffer from charging loss. And is your solar controller efficient enough?. Because if you have a cheap controller that will also affect charging.
Location in relation to the sun
This is really important in relation to harvesting sunlight. If you have installed the 200w solar panel flat on your vehicle’s roof. You are only going to receive the most powerful sunlight when the sun is directly overhead. That is about 4 hours per day. And in winter, the fall and spring the sun is weaker which will further reduce output. If you mount the panel using a frame to stand it upright on the roof. That could help, but you would have to move your vehicle to follow the sun. A portable solar panel is more flexible because you can point it directly at the sun all day. Whatever the season.
If you are fortunate to live in or are traveling to a state or country where sunshine is plentiful. Weather conditions might not be a big consideration. But if you are traveling to a location with variable weather conditions. You need to know that the 200w solar panel will still work but at a reduced rate of up to 60%. So on cloudy days you should limit your battery use. Or you can just run the generator or engine if necessary. To make sure that the battery doesn’t deplete too far. And pick up solar charging again the next day.
Charging A Portable Power Station With A 200 Watt Solar Panel
In case you didn’t know. A portable power station is a battery with a built-in solar controller and inverter. A great example is the EcoFlow River 600 Max Portable Power Station. These types of batteries have their output described as watt hours (Wh) and/or amp hours (Ah). The River Max has a 576Wh and 28.8V rating. So If I divide 576 by 28.8 the Ah is 20
The Jackery Explorer 1000 Portable Power Station.has a 1002Wh and 21.6V rating. So if I divide 1002 by 21.6 the Ah is 46.4.
This all means that a leisure battery has a far longer run time. Run time means how long it will last under a load. The load is an electrical appliance such as a TV. And looking at the 2 portable power station examples. The River Max has more power 28.8V than the Explorer 21.6V. But has less staying power 20Ah V 46.6Ah.
Working out the time it will take for a 200 watt solar panel to charge a battery
All this means that a 200 watt portable solar panel is very capable of charging these portable power stations. The theoretical way of working out how long it will take to charge a battery. Is to divide the watt hours of the battery by the solar panel watts. So for this we will use the Jackery Explorer. This has a watt hour rating of 1002. So if I divide 1002 by 200 that equals 5. So theoretically it will take 5 hours under full sunlight to charge the power station.
But taking previously discussed considerations into account, this can only be a very rough estimate. I believe it would be reasonable to double the time to 10 hours. So I would use this calculation; 1002Wh divided by 200w equals 5 times 2 equals 10 hours. Using this calculation with the River Max it would be 5.76 hours. And remember this is under full sunlight. But it is unlikely that you would allow the battery to deplete to zero. Topping it up will be much faster.
My Closing Thoughts
Now you know that a 200 watt solar panel will effectively charge one battery. If you have two batteries you will have to consider purchasing another. If you have a recreational vehicle it might be better if you use 4 x 100 watt solar panels. This will provide a larger surface area to capture sunlight. If you don’t want to install solar panels you can use a portable with a built in controller. And if you want to charge a portable power station you can use a 200w panel. But be aware with a portable you may have to use a bit of DIY. This is because the connection cables may need adjustment.
I hope you enjoyed my post and have found it helpful. If you have any questions about 200 watt solar panels. Or want to leave your own personal thoughts, please feel free to leave a comment below