What Size Solar Panel Do I Need to Charge My RV Battery

What Size Solar Panel Do I Need to Charge My RV Battery

If you are taking your RV on camping trips– or on any other sort of trip– you will want to be sure that you can charge the battery of the vehicle. Solar power is a great resource and is easy to access when out on a camping trip, but you should also be sure that you have chosen the correct size of solar panel to charge the battery as needed. Read on to learn more about how to find the best size of a solar panel for your RV’s battery. 

Types of RV Batteries

Not all RVs have the same kind of battery, either! There are four main types of battery that you can find in your RV, which we will go into greater detail on below. 

Lithium Ion Batteries

Lithium-ion batteries are one of the newer types of RV batteries out there. One of the main benefits of this kind of battery is that it can last much longer than older lead-acid batteries. Lithium batteries can last between 5 to 10 times longer than some of the other types of batteries around. In addition, they can store up to 4 times as much energy as lead acid batteries can. They also have a longer lifespan in general. 

Wet Cell or Flooded Batteries

Wet cell or flooded batteries are some of the most common RV batteries that can be found on the market. They do require maintenance to keep them running and at their best, including regularly topping them up with water. They are also sensitive to damage from knocking or shaking, which could cause them to lose charge.

Gel Cell Batteries

Gel cell batteries are a kind of sealed lead acid battery. They use fumed silica and sulfuric acid to form a gel-like substance that doesn’t move around. Due to this, these kinds of batteries can be placed in different positions and go through bumpy journeys without losing charge. 

Absorbent Glass Matt Batteries

These particular batteries are another type of sealed lead acid battery. They originated in the 1970s and contain a mix of electrolytes, fibreglass, and sulfuric acid. Their spill proof, and like gel cell batteries, can be moved around without damaging them. 

Calculating the Size of Your Solar Panel

There are many online resources where you can calculate the size of the solar panel you need by inputting the values and pressing the button. However, it is not very difficult to calculate this manually, either. Essentially, Power = Voltage x Current. Multiply the voltage and current of the battery to find out the amount of power (in watts) that you will need in a solar panel to charge the battery. You may also want to round your answer up to a multiple of 100 to ensure that you will have enough power when you set up your solar energy system. 

What Size Solar Panel Do I Need to Charge My RV Battery?

RV batteries typically come in 12-volt configurations. This means that, when you are trying to figure out what size solar panel you will need to charge the battery, you should be doing your calculations based on 12 volts. Generally speaking, any solar panel is going to be able to charge a 12-volt battery, as long as the voltage is above 13.6 volts. You will want to be sure, though, that you choose a panel that will be able to maintain your battery and recharge it quickly if needed. Also, you should always ensure that your solar energy system is set up with a charge controller to protect your battery. 

If you assume that the 12-volt battery charges at 20 amps, you would need at least 240 watts of power to charge the battery. You can then round up to 300 watts to be sure that you have enough power and can either buy a 300-watt panel or three 100-watt solar panels– whichever configuration is your preference. 

Frequently Asked Questions

Will a 100-watt solar panel keep my RV battery charged?

A 100-watt solar panel may be enough power to keep your RV battery charged, provided that it is constantly sunny and without cloud cover. However, generally speaking, this size of solar panel will likely be unable to fully power your RV battery, especially in cloudy areas. 

How big of a solar panel do I need to charge a deep-cycle battery?

If your deep cycle battery is 100Ah and is discharged to 50% of its total capacity, it will need at least 2 solar panels that are rated at 100 watts each. This will allow the battery to recharge in a day– you will want to be sure you are able to quickly recharge your battery, especially when it is an RV battery that you are using on trips!  

What size solar panel do I need to trickle charge a 12V battery?

If you have a 12V battery, you could use either a 5W or 10W solar panel to trickle charge it. This means that you are slowly charging the battery and constantly maintaining its charge. If you do choose a 5W or 10W solar panel, these are perfectly suited for slowly charging up the battery over a course of a few weeks– rather than quickly, in a few days. Depending on the size of the battery, it may even take longer than a few weeks to trickle charge the battery. 

How long does it take a 100W solar panel to charge a battery?

Part of the answer to this question depends on how much of the battery has been discharged. For instance, if you are charging a 100Ah lithium iron phosphate battery, which has discharged 80% of its energy, a 100W solar panel would take about 20 hours to fully recharge the battery. It is recommended, though, that you set up 250W worth of solar panels to charge a 100Ah battery in one day. 

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