The new RV Camper that has been manufactured in the last few years is either Solar ready or comes with solar equipment already installed but if you’re like me you’ve been camping for years but need to make sense of everything else involved Solar, so let’s start with Equipment that is needed. What are the components of a solar PV system?
- Solar Panels-converts sunlight to Energy
- Charge Controller-organizes energy collected by Solar Panel
- Batteries-stores energy from Solar Panel
- Inverter Charger-charges battery from other sources
- DC Inverter- takes DC power in battery-converts it to AC
- Isolator-uses engine’s alternator to charge a battery
As Solar power comes to fruition and enters the world of Outdoor Recreation it makes sense to inform yourself the very basics to take advantage of what is a growing subject.
RV Solar Power Systems
Solar Panels– Solar Panels are the most recognizable component in the system. The panels are usually but not always located on the roof of an RV, residence, or vehicle for easy access to the sun where it takes sunlight and converts the sunlight to electricity called The photovoltaic effect. This process gives solar panels their alternate name, PV panels.
Solar panels are rated by the output in Watts. This rating is the maximum power produced by the panel under ideal conditions. Output per panel is between 10 and 300 watts, with 100 watts being a common output.
There are 2 main types of Solar panels:
Monocrystalline and Polycrystalline in which differ in their efficiency and although they are basically the same size Monocrystalline will deliver more power with a small amount more expense.
Fixed Mount– Panels-Because the angle of the sun changes throughout the year, the height and angle of fixed mount Panel arrays are a trade-off for an optimum power angle for a less expensive, less complex installation.
Tracking Mount Panels-move with the sun. The tracking array moves east to west with the sun and adjusts its angle to maintain the optimum as the sun moves for the best output power.
Charge Controller- The Charge Controller takes the power from the Solar Panel organizes it and converts that energy to be readied to use. The power that comes from the Panels is at varying voltages from 16 to possibly hundreds. The Charge Controller Converts the varying voltages and reduces them from 12.6 to 14.6 volts which will accommodate your 12-volt battery bank. An off-grid inverter/charger would be converting the power in both directions, from AC to DC to charge the battery from the AC generator, and converting the DC power from the battery to AC for your appliances.
Batteries– Batteries are the storage tank for the power you created with the Solar Panels and Charge Controller. There are 3 types of Batteries sold Lead Acid, AGM, or Absorbant Glass Mat, and Lithium. Many experts on this subject don’t recommend the standard Lead Acid Battery but AGM and agree that AGM and Lithium are the best way to go lightweight and more bang for your buck. With Lithium the better of the two.
DC Inverter Simply put the Inverter will take the power that is created and stored in the Battery as DC power and converts it to AC Volts which in turn will run normal small household appliances like Coffee pots or Televisions. In an RV or Off-Grid system
Inverter-Charger– would convert the AC power from the generator to charge the DC battery bank. Charges and keeps your Battery Bank charged up using shore power at a campsite or through another source on the grid. These guys come in hi-speed chargers at 40-70 amps. The Inverter Charger is necessary, especially if you are away for more than short trips or depend on more than a few appliances.
Isolator– This device will allow you to charge your battery bank with the Vehicle’s engine alternator. It will open and close when the engine is running or turned off, so you don’t drain your starting battery when using your Solar Batteries.
There are odds and ends that will be added to a Solar System like breaker panels, fuses, wiring, or voltmeters that if you tackle this project you should be a little familiar with how electrical wiring and electrical safety work in your own home.
RV Solar Panel Size Calculator
The main question you need to answer when trying to calculate RV Solar Panel Sizes is answered how many batteries do you have? How long can you dry camp on those batteries that are fully charged? The average RV would have a 27 Series Battery.
That Battery would contain a hundred amps of storage in it. The average Camper will go camping for 2 days and will have enough Battery life for 2 days with those fully charged batteries. So what that says is that on average you use 50 amps of power each day. This is why Campgrounds either give you 30 or 50 Amp service at your site when you camp.
If your Solar Panel is a 160-watt-sized panel and it’s adding 30 amps per day and you’re using 50 amps per day, your batteries would now be good for 5 days of camping by adding 1 small panel.
A larger 250-watt panel can put out 50 amps per/day and if you are consuming 100 amps per/day then you are replacing half of what you are consuming.
By adding several Panels, you can actually become self-sufficient by adding what you are consuming. So the very first thing that you need to do in determining what size or how many Solar Panels you need you first need to estimate your daily energy usage. The energy used to operate the electrical device that you are operating in Watts. The wattage used will tell you:
- The size of Battery Bank you will need is based on the number of days you will be able to dry camp without running on Shore power or a portable generator & without recharging.
- The Wattage will also tell you how many Panels you will need
- The size Inverter you will need
The wattage for an appliance can be found on the label directly on the appliance or device. It is listed specifically as Output Wattage. Once you get this information use the formula, Watts, = Volts x Amps
If you don’t get Watts then use Volts x Amps and that will give you Watts. If you only get Milliamps then use the formula Milliamps divided by 1000 = Amps then Watts =Volts x Amps this will get you back into Wattage.
Once you know what is the combined Watts you and your family use for the appliance then you need average Daily use Watts. Some devices run 24 hrs. per/day some only run half that time maybe 12 hours per/day.
Once you figure out the hours of running time and the number of Watts, this will give you the true number, and now you can size up your Batteries. Most people want to size their Batteries by using 2 days of use without needing to be charged or Dry use.
Battery Sizing Calculator
Take your personal information that you estimated and use it to find the right Batteries for your needs. Fill in your estimate for average Watts and you can account for some devices you won’t use if you are in an emergency situation, you might not use the air conditioning.
Most people want to size their Batteries by using 2 days of use without needing to be charged or the Dry use.
These calculators will link up to whatever information you may need including what dimension and how many Solar Panels, their price in whatever location, and State you are in. What size Controller you will need for the system according to the Solar Panel information that you used in the calculator.
References: Clean Energy.Authority.com