N-Type Solar Panels for Off-Grid Living: 12V 175W & 24V 200W Options

Whether you are living in an RV, off-grid cabin/home, or boat, you can power everything from lights and computers to refrigerators and instant pots with energy from the sun. We've been powering our off-grid RV life for over 12.5 years as we've traveled, worked, and played around the North American continent. Designing a solar powered system that works for your rig / home, your lifestyle, and your energy needs is key to success and satisfaction with your system!

When building a system, folks often start by researching solar panels options. You'll immediately note that the most common panel voltages are 12V and 24V, which refers to the maximum system voltage a single panel is designed for – and this voltage directly impacts system performance and efficiency. With a deeper dive into the specs, you'll find that panels come in various wattages and styles. Going further, you learn that both 12V and 24V panels can be set-up in various configurations and roof top panels can be combined with portable panels, offering different advantages depending on how you plan to use them.

Wait a minute! What does all this mean? Trust us, you are not alone if these terms and specs are downright confusing. We were there over a decade ago…and now we teach it! Let's break down some of these terms and discuss what voltage means, what 12V and 24V refers to in solar panels, the major differences between the two voltages, and what they are best used for.

What to Consider When Choosing Between 12V & 24V Solar Panels?

First off…let's start with solar panel voltage? Voltage (V) refers to the electrical pressure that is created when the sun illuminates a solar panel and that energy is sent through the wires from the solar panels to the charge controller. The charge controller then regulates that pressure, allowing the battery bank on the other side of it to charge appropriately.

When looking at specs for solar panels, you will see 3 key types of voltage:

• System Voltage: This refers to the system's “nominal” voltage, or the system voltage for which a specific panel is designed. A common specification you will see is “12V” or “24V.” A single 12V solar panel is only compatible with a 12V battery system (if there is no boost controller), while a single 24V solar panel has the flexibility to work with either a 12V or 24V battery system.
• Voc: Stands for Voltage Open Circuit (aka “Open Circuit Voltage”) and refers to the maximum voltage a solar panel can produce when it's not connected to any load or circuit. Think of it as the solar panel's untapped potential, the absolute upper limit of the voltage it can generate under perfect (laboratory) conditions.
• Vmp: Stands for Voltage Maximum Power (aka “Optimum Operating Voltage”). It is the voltage at which a solar panel generates its maximum power output when the solar panel is connected to a load or circuit, and is also operating at peak efficiency. This is the sweet spot when your solar panel is cranking out the most electricity it possibly can – and you're getting the most bang for your buck.

For example, Renogy's N-Type 12V - 175W solar panel has a Vmp of around 21V, ensuring a single 175W solar panel can efficiently charge a 12V battery system. Similarly, their N-Type 24V - 200W solar panel has a Vmp of around 31V. A single 200W solar panel can be compatible with both 12V and 24V systems.

Why is the Vmp so much higher than what typical batteries can accept? Great question! Panels are specifically designed to generate a higher voltage than the system voltage that they are designed for so they can respond to changing atmospheric conditions (e.g., low light, high temperature environment, passing clouds) and any energy transmission loss that happens when the direct current (DC) electricity passes through the length of wire between the panels and charge controller. As a side note, MPPT solar chargers make use of that extra voltage to charge your batteries even faster, which is why they are so more efficient than PWM type charge controllers!

Next, let's take a quick peek at a couple of other terms that are going to come up when researching solar panels:

• Amperage (A) – aka amps – is the flow of electricity (or current) running through the wires from panels to charge controller. When combining panels together, a series connection will keep the amperage the same and increase the voltage of the total array. A parallel connection does the opposite. Using the example above, Renogy's N-Type 12V - 175W solar panelgenerates an optimum operating current (aka Imp which stands for Instantaneous Current at Maximum Power) of 8.38A per panel and the 24V - 200W solar panel can generate up to 6.45A. While just about any Renogy charge controller can handle 1-2 panels of this type of voltage, if you are building an array with 3 or more panels, you'll want to consider how the configuration of your array* (multiple panels connected together) will impact the size of the charge controller.
• Wattage/Power (W) – aka watts – is the product of the volts times amps. To be even more specific with solar panel ratings, it is the Maximum Voltage Power (Vmp) times the Instantaneous Current at Maximum Power (Imp), or Vmp x Imp = W. In general, watts refers to the overall work that a panel can do for you and is often listed in the product's title. But, not all panels of the same wattages are the same dimensions or offer the same efficiency. It's always important to check the specs!

What are the Overall Advantages of 12V and 24V Solar Panels?

How will you be using your solar panels? In what type of dwelling will you be living and what types of appliances will you be powering?

In general, 12V solar panels are best suited for small systems such as RVs, boats, portable systems, and small cabins. They are ideal for setups with minimal energy needs, small spaces with short wire runs. Conversely, 24V solar panels are better for larger, more power-hungry systems like residential set-ups, larger off-grid cabins, and commercial applications. They are excellent for large spaces and installations with longer wiring distances or where higher efficiency is crucial.

*It's important to note that both 12V and 24V solar arrays can be set up in parallel, series, or a combination of both. Different configurations (series vs. parallel vs. combination) will achieve the same overall array wattage, but will drastically affect the voltage, amperage, and in turn, wiring size, charge controller specs, and cost. It's important to learn more about different configurations and how they affect your overall system before choosing your other components.

Is 12V or 24V better? Here's a quick look at some advantages for each overall system voltage:

12V Solar Panel Advantages:

• Direct compatibility with 12V systems typically used in RVs, boats, and small off-grid cabins.
• Lower voltage makes these panels easier to wire and connect to controllers and batteries, especially in small setups.
• Lower voltage panels are more suitable for a series configuration when connecting many together.
• Easier to coordinate and connect to other solar system components like controllers and inverters with lower voltage input limits.

24V Solar Panel Advantages:

• Higher voltage means lower amperage, resulting in less heat generation, and more efficient power transfer over long distances (aka less transmission loss).
• Reduced wiring size (thinner cables), allowing you to save money on overall material costs.
• Ideal for larger systems, as fewer panels are needed for the same output.
• Less voltage drop over longer cable runs, increasing efficiency in larger setups.
• When using 24V panels, ensure that the charge controller's maximum PV input voltage matches the solar panel array's output!

Solar Panel Specs	12V N-Type Panel	24V N-Type Panel
Wattage	175W	200W
Open Circuit Voltage (Voc)	24.48V	37.44V
Short Circuit Current	8.88A	6.85A
Optimum Operating Voltage (Vpm)	20.88V	31.03V
Optimum Operating Current	8.38A	6.45A
Max System Voltage	600VDC	600VDC
Dimensions	43.7 x 30.1 x 1.2 inches 1110 x 764 x 30 mm	49.7 x 30.1 x 1.2 inches 1262 x 764 x 30 mm
Weight	21.2lbs 9.6kg	23.4lbs 10.6kg

What are N-Type Solar Panels?

N-type solar panels have a different chemical composition than the more common P-type (PERC) solar panels, which makes them negatively charged, hence N-type. These solar cells achieve a cell efficiency of 25%, which is 2.5% greater than traditional P-type cells. The 16 busbar design of N-type cells maximizes energy conversion and reduces the possibility of microcracks through better heat distribution. Also N-type cells aren't as susceptible to sunlight induced degradation as P-type, which contributes to their longevity. At the same wattage output, these panels can be between 4-7.5% smaller and 4-11.7% lighter. While at first glance, these improvements aren't super significant, they definitely add up quickly. They are a little more expensive to manufacture which explains the price difference.

12V - 175W N-Type Solar Panel

• Perfect for Class B vans* and smaller RV's – 3.9% smaller, 4% lighter
• Great for 12V cabins, sheds, sunroom, and greenhouse owners
• Ideal for marine use (catamarans, sailboats, etc.)

Key Features:

• 25% efficiency with N-type cells for higher output and durability
• Low temperature loss and high heat resistance for hot climates
• Built to last with a corrosion resistant design plus corner guard
• ≤1% first-year power loss and 25-year 80% output

24V - 200W N-Type Solar Panel

• Perfect for Class B vans* and smaller RV's – 7.5% smaller, 11.7% lighter
• Great for homeowners with rooftop solar
• Ideal for marine use (larger boats, etc.)

Key Features:

• 25% efficiency with N-type cells for higher output and durability
• Single panel compatible with 12V & 24V systems for versatile use
• Low temperature loss and high heat resistance for hot climates
• ≤1% first-year power loss and 25-year 80% output

*These Renogy's N-type panels are some of the most efficient cells on the market, and are shaped perfectly to fit on top of most Class B vans. A win-win for those of us who live in small spaces!

What are Some Factors to Consider When Choosing Your System Size?

Calculate System Size & Power Requirements: Smaller systems or those with low power needs may do better with 12V panels, while larger systems require 24V for better efficiency, especially those with longer wire runs.

If you are just planning to just power lights, fans, charge your laptop and smartphone, and a couple of small kitchen appliances in your van or small RV, a 12V system is perfect. But, if you want to run many of the types of appliances found in a traditional home, a 24V (or even 48V) system is going to serve you well.

For the most cost-space-benefit, here's a good rule of thumb that engineers use to determine the best voltage configuration for your system.

If your total solar array capacity is:

• < 1000W then12V is Good
• > 1000W and < 2000W then24V is Better
• > 2000W then 48V is Best

Note: If you haven't yet done an energy audit to determine your power needs, calculated the size of your system, and selected the components you need, download our free comprehensiveSolar System Sizing Worksheet that we use when teaching our RV Solar 01 seminars. The worksheet will help you build a system and create an organized order for all of the components, wiring, accessories, and mounts that you will need.

Note: The wire length unit in the chart is in feet.

Select Wiring for Best Efficiency & Safety: If you are building a larger system for a home or very large RV, 24V systems offer lower transmission losses, making them better for long distance set-ups or high power needs.

The greater your energy demand, and the more powerful your appliances, the greater the amps that will need to flow through the wiring – especially if they heat (e.g., hair dryers, coffee makers, space heaters, instant pots) or cool (e.g., air conditioners and refrigerators). The greater the amps, the larger the wire gauge (thickness) has to be for safety – and, not surprisingly, larger gauge wiring is more expensive. But, if you increase the voltage of your system, you can decrease the amps flowing through the wires, increase the efficiency of your system by reducing transmission loss, ensure overall safety, and reduce the wire gauge – and ultimately decrease the overall cost of a solar powered system. Definitely a win-win-win!

Solar Panels	12V	24V
Ideal Use	RV's, Boats, Portable Systems, Small Off-Grid Cabins	Residential, Large Off-Grid Homes, Commercial
System Size Recommendation	≤ 1000W of Solar	≥ 1000W of Solar
Wiring / Efficiency	Ideal for shorter wire runs	Ideal for longer wire runs
Battery Voltage	12V for optimal performance*	24V for optimal performance*
When Upgrading	Ensure charge controller and max PV voltage input compatibility / max PV power input compatibility	24V charge controllers can typically handle adding on extra panels, but still ensure charge controller and max PV voltage / max PV power input compatibility
Future Expansion	More considerations when expanding: wire size, component compatibility, fuse sizes, etc.	Easier to scale up for larger systems.

*Since charge controllers with MPPT have a wider voltage range, they can better handle working with solar arrays and battery banks of different voltages.

Check Battery Bank Voltage for Compatibility: Can I connect a 24V panel to a 12V battery? In short, yes, as long as the charge controller can handle the additional voltage; but ensuring that the solar panel output voltage matches the battery system input voltage will provide optimal performance.

The same series-parallel configuration we discussed with solar panels can be applied to batteries. Connect batteries in series to increase the voltage, while keeping the Ah capacity the same; or arrange them in parallel to increase the Ah capacity, and keep the voltage the same.

All flooded lead acid and solid lead acid (Gel or AGM) can be connected in either parallel or series. Some Lithium Iron Phosphate (LiFePO4) batteries may only be connected in parallel, while more modern ones such as Renogy's Core series are designed for series or parallel connections. While most RVs and vans come equipped with lead acid batteries, LiFePO4 batteries are a true game changer as they give you nearly twice the usable watt hour capacity of any lead acid, charge faster, are lighter weight and smaller – allowing you to greatly increase your battery bank capacity in the same space! Some LiFePO4 batteries also offer Bluetooth for wireless monitoring and self-heating functions for cold weather adventures.

Ensure Inverter Compatibility

The whole point of a higher voltage system is to be able to run higher wattage AC appliances without over-wiring the whole system. To do this, you need to connect an inverter to the battery bank. It is important to match the battery bank voltage with an inverter that can handle that same voltage. Simply put, if you have a 12V system, you need a 12V inverter; a 24V system requires a 24V inverter. Or, if you have a 24V battery bank, you need to install a step down converter for it to be compatible with a 12V inverter.

Upgrade an Existing System? If you're retrofitting an older system, be sure to calculate the total Voc (Open Circuit Voltage), total Isc (Short Circuit Current), and total Power (wattage) of your new solar array and compare these specs to the max PV input voltage, amperage, and power of your existing charge controller to ensure its compatibility. If it cannot adequately handle the new specs, we recommend replacing it with an MPPT Rover charge controller for maximum charging efficiency.

Plan for Future Expansion? All solar power systems are scalable, but if you're working with 12V, you need to pay close attention to wire size, component compatibility, and fuses. If you have plans to build a much bigger system later on, 24V panels may be more scalable in the long term. It all depends on how large you plan to expand. Keep these recommendations in mind:

If your total solar array capacity is:

• < 1000W then12V is Good
• > 1000W and < 2000W then24V is Better
• > 2000W then 48V is Best

While we know that this is a lot to take in, especially if you are new to solar. Keep the following in mind when deciding whether 12V or 24V is right for you:

• 12V panels are ideal for small, low-power systems, while 24V panels are more efficient for larger systems and those families with higher power needs.
• Choosing 12V over 24V depends on your overall system size, power demands, and the need for future expansion.
• If you're looking for simplicity and low initial costs, go for 12V. If you need efficiency and have larger power requirements, 24V is the better choice!

In 2012, Shari Galiardi & David Hutchison left behind careers and a comfortable home in North Carolina to travel with the vintage camper trailer they lovingly restored, outfitted with solar, and named "Hamlet." What began as a short break from careers and responsibility quickly turned into a love affair with roadlife. They have parlayed their higher education backgrounds, desire for life-long learning, and thirst for adventure travel into writing, photography, video production, and public speaking gigs from coast to coast. Known to their friends as simply Shari & Hutch, you can learn more about their full-time, solar-powered adventures on their website at freedominacan.com. Or, follow them on Facebook, Instagram, and YouTube as “Freedom in a Can, LLC.” Use our CANLIFE promo code to save money on Renogy components at renogy.com.