Because RVs come in many different shapes and sizes the best 200W solar array will also vary a lot. But first lets discuss what is the best size panels for your needs.
Is 200W Big Enough?
In full sun a 200W solar panel will make 200 Watts of power every hour at the maximum. This is 16.6 Amps at 12 Volts output.
Assuming that your battery system is 12V 100AH, as most RV systems are, then this is what you can reasonably expect.
Putting this through a smart charger will charge a typical 12V battery from low charge to full in about 4 hours.
There are many variables in this calculation that can change the charge rate from the angle of the sun above the horizon, if the solar panels are fully facing the sun, the age of the batteries, the discharge percentage at the start of charging and even if you do get a full 4 hours of full sun.
Because of this the information here is based on maximum benefit and you will probably find that full charge takes an hour or two longer because most panels will give about 80% of the rated output.
Is Bigger Better?
The answer to that is ‘that depends’.
The reason is that the limitation is the maximum rate of charge your battery system can handle.
Most battery manufacturers recommend that the maximum charge rate should be no more than 25% of the AH rating of the battery. For the system we are modelling here that would mean a maximum of 25A.
The smart charger will manage that for you but putting excess power into the charger will just be wasted as it will not be used.
However, in less than optimal conditions, you may get a benefit from having 2 x 200W solar panels on your RV.
By combining two solar systems you could get between 200W & 300W when a single system would only provide 100W to 150W output.
What you have to balance out is the increased cost of the panels and the additional surface area you need or the extra storage space for a portable system for the relatively small benefit of faster charging in poor conditions.
That is of course if you use fixed solar panels to your RV roof.
What Are The Advantages Of Portable 200W Solar Systems?
If you use portable panels then you can park your RV in the shade and put the panels in the full sun. You can move them around to maximise the power generated and generally get the benefits of solar charging without having to park your RV in the full sun.
- No risk of accidental damage while travelling.
- Keep the RV in the shade and cool while still getting full charge.
- Keep the solar panel charging close to maximum by moving it around.
- Can have a smaller unit to keep your RV power supply charged.
- Can be swapped between RVs easily for changeover or if you have another vehicle or boat.
Can A 200W Solar Panel System Be Used Off-Grid?
Yes, these are all off-grid systems. They are not designed for permanent off-grid living.
If you want/need to supply your home or holiday place a single 200W system will probably not be big enough.
This is big enough for most RVs, small yachts, holiday or tiny homes.
Most modern homes draw about 7kWH of power at peak and average about 30kWH per day. To supply this you would need a battery bank capable of delivering that and an inverter which can handle the peaks. Using 400AH batteries as an example you would need about 6-7 12 volt batteries to deliver the required power. If you want to cover days of low/no charge then you need to multiply this by the days you expect there to be a problem.
The physical dimensions vary a little as monocrystalline panels generate a little more per area than polycrystalline and the framing of any panel can be different. Realistcally though there is little difference between them so use these dimensions as examples rather than guaranteed sizes.
The Renogy panels are 47″ x 21″ x 3″ (1193mm x 533mm x 76mm)
The Windy Nation panels are 40″ x 28″ x 4.5″ (1016mm x 711mm x 114mm)
The Eco-Worthy folding panels are 52.5″ x 39.3″ x 1.4″ (1333 x 998 x 35mm) unfolded and 26.1″ x 39.3″ x 3″ (663 x 998 x 76mm) folded.
How Much Do 200W Solar Panels Cost?
That varys depending on the type of cell used.
Monocrystalline cells are the most efficient, last the longest and are the most expensive.
Polycrystalline cells are less efficient, don’t last as long but are cheaper.
Amorphous cells are even less efficient, don’t have a long life span but are quite cheap and are not usually used for home sized systems.
As a rule of thumb you would pay $100 – $150 per 100W panel. Obviously you will pay more for a kit and you will need the extras in a kit if you don’t already have a system installed that you are just adding to.
This means that you would expect to pay around $300 to $500 for a 200W kit with good quality components, mounting brackets, cabling etc.
The current crop of solar panels rated at 200W will cost about the same regardless of the type of cell used. Even the dimensions don’t vary much and can be attributed to the frame and other hardware as much as anything.
What Will A 200W Solar Panel System Run?
Because most electric motors have a starting current which is greater than their running current 200W will not usually be enough to start anything but the simplest motors.
Most laptop computers require around 250W to run so they are out of the question as well.
You could run a couple of light bulbs but that seems rather pointless during the day when the sun is shining doesn’t it?
They will charge your phone or other small devices but there are better, and cheaper, ways to do that.
It isn’t possible to directly run very much at all from a 200W solar panel but that isn’t what they are good for.
They are excellent at charging up one or more batteries which you then use either directly or though an inverter to run many of those electrical and electronic devices we all seem to need these days.
During a 6 hour charge day a 200W system can store up to 1200 watts of power which won’t run your airconditioner but will run your laptop and your LED TV. It’ll charge up your phone and your Kindle and run your lights.
I have seen videos on YouTube which claim to show a solar panel running all sorts of high load devices. These are a bit misleading as the panels are also connected to a battery and it is the battery which is running these items with the assistance of the solar panel. If the battery was disconnected the panel alone would not run these items.
Building a portable solar power system is a pretty straight forward thing to do. Particularly if you have some idea of 12V electical wiring.
Firstly you will need to buy the panels.
Most of them these days come with output leads that are rated for the expected output but they are not usually very long so you will need to add cable to you shopping basket.
This cable will need to carry up to 16A but that is automotive sized cable and easy to find.
You will need a charger, batteries, fuses, mounting brackets cable joiners and or termination lugs. Most of the smart chargers come with instructions on how to hook them up as do the solar panels.
I think that a multimeter is a useful tool to make sure that you have everything hooked up the right way round before you connect the charger and again before you connect the battery. Sometimes the wiring isn’t right and you need to be sure that you correct anything before damaging sensitive electonic components.
Depending on your installation an isolation switch might be a good idea. The system on my caravan uses Anderson plugs to connect to the battery so I can also charge from the car or easily disconnect the whole system for packing away.
In this way I can also add an extra battery for longer use of the stored power at night.