Solar Products FAQ

A solar charge controller acts as the “brain” between your solar panels and your batteries. It regulates the unpredictable voltage and current from the solar panels to manage safe battery charging.

It prevents overcharging, regulates voltage, and ensures your battery bank charges in a safe, controlled way. Without one, solar panels could damage a battery by pushing in unregulated power.

At Sapphire, controllers are chosen to match our LiFePO₄ batteries perfectly, so you get maximum performance and lifespan from all of your gear.

PWM (Pulse Width Modulation) controllers are a very simple and affordable technology, that has been around for decades. They work by turning on/off rapidly, creating a pulsing voltage signal to simulate a proper charging voltage.

This works ok for lower voltage arrays, but wastes a significant amount of energy on higher voltage panels, and potentially risks damage to control circuits on the batteries. PWM is lower cost, but lower efficiency.

MPPT (Maximum Power Point Tracking) controllers do exactly what the name implies. They use advanced electronics and actively adjust their behavior to pull the most power possible from your PV array. This is accomplished by actually transforming the excess voltage, into current that can be funneled directly into your battery system.

This boosts efficiency by up to 30%, and makes higher voltage arrays possible, reducing wiring costs. MPPT is almost always worth it. See our blog posts for deeper dives into MPPT vs PWM.

Simple Answer: Controller sizing is based on both amps and voltage. Divide your total solar panel wattage by your system's battery voltage to find the max current, then add a 20–25% safety margin. For example, a 220W panel on a 12V system produces ~18A, so a 20–30A controller is recommended.
View our Solar Panels and Charge Controllers

Yes! It's one of the most popular ways to charge them.
Many modern controllers include lithium charging profiles built in.

Each controller has a marked maximum wattage and voltage input.

Moderate oversizing is fine—the controller will “clip” excess power—but never exceed its voltage rating. Check the Voc ratings on your panels, and be aware that colder temperatures will increase the panel output voltage. Leave yourself a margin so you're not stressing your controller.

When in doubt, it's always better to have a controller that is rated for more than you're connecting. It will help the controller run cooler, longer.

Not necessarily. That is a separate function in the system.
The solar controller's job is to manage DC charging only. What you do with that newly charged battery power is up to you.

To power AC appliances like microwaves, laptops, or TVs, you’ll need an inverter.

It’s possible but not recommended. Panels of different wattages/voltages drag each other down, reducing efficiency. There is also risk of over stressing things like bypass diodes and internal busbars in the panels.

Best practice is to use matched panels.

Modern controllers have many safety features built in to protect both the controllers themselves, and the batteries they charge. Things like temperature limitations, and low/high voltage safeties to disconnect from batteries that are operating outside their design specifications.

Some are, but most are IP20–IP32 rated, which means dust and very light splash resistance but not waterproof.

Some of our RV controllers are IP54 giving you excellent dust and water protections, and there are IP65 models available for fully outdoor installations.

Generally though, it's best practice to mount the controllers inside a clean, cool, dry space. If you're note sure, contact us and we're happy to help.

Always use properly sized fuses, breakers, and disconnects. A remote temperature sensor can improve charging accuracy in extreme climates, especially with lead batteries.

Sapphire offers disconnect switches and accessories designed to work with our batteries and controllers.

A quality controller, installed properly, can last 10+ years. Install it in a cool and dry, well ventilated area for best performance.

Our MPPT units are designed for long-term reliability to match the service life of our Solar Panels, and our LiFePO₄ batteries.

Solar charge controllers should ALWAYS be used when dealing with solar power and battery systems. It's the only way to safely harness the sun's energy through your PV array.

Controllers are commonly used in van builds, RVs, cabins, boats, tiny homes, and emergency backup power kits. They’re also great for specialized uses like powering security cameras or farm gates.

See our Blog Articles for ideas and more information

Size depends on your daily energy usage and sun hours. A van fridge and lights often need ~200W, while cabins may need 400W+.

Start with discovering your daily power needs, cross checked with your battery sizing. See our article about sizing your battery for a good place to get started.

Yes. Panels can be wired in series (higher voltage) or parallel (higher amps).
Be sure to consider the limitations of your charge controller when adding more solar.

Oversizing wastes excess solar as the controller clips output, but it can give you more energy production in low-light conditions (like the fall/winter).

Under sizing will leave batteries undercharged, and you may struggle to keep the lights on. This may require you to augment your battery charging with things like DC-DC Engine Charging, Shore Power, or a generator.

Monocrystalline panels are a newer technology and are more efficient. This means a 100W panel takes less physical space (potentially allowing more panels in a given space). Things like the Polycrystalline-PERC cells take this one step further and even improve low light response. Our Lumera brand panels feature this proven and reliable cell technology.

Polycrystalline panels are sometimes slightly cheaper, but are an obsolete technology and it is recommended to avoid new installs using these.

Yes—panels produce power in diffuse light, though output is reduced. Expect 10–40% of rated power on heavily clouded days. Winter actually offers some of the best temperatures (Solar likes it cold) but things like snow buildup, and low angles from the sun will reduce your output. Consider tilting your panels towards the winter sun to improve productions.

MPPT controllers can help maximize energy, even in sub-optimal conditions. Many people will "over panel" when they expect low production.

Most modern panels carry 20–25+ year performance warranties. They degrade slowly—typically only ~0.5% per year—and continue producing well beyond the warranty period. A good investment for long-term off-grid power.

Yes. Quality panels use tempered glass and aluminum frames tested for hail, snow, and heavy rain. All panels we carry are built for Canadian weather conditions.

Very little. Occasionally rinse off dust, pollen, or snow to restore efficiency. Inspect mounting and cabling once or twice a year. Panels are designed to be low-maintenance for decades of service.

When washing, use a non abrasive brush/cloth and a gentle soap.

Use a soft edged brush, or wiper, to remove snow and ice. Avoid hitting/impacts or using heat.

Many vanlifers and cabin owners DIY their installs. Panels are relatively simple to mount, especially with plug-and-play wiring kits. For rooftops or high-voltage systems, a licensed installer is recommended for safety and compliance with local regulations.

In Canada, panels perform best facing south at a tilt close to your latitude. For users in the southern parts of the country, 45° is a great balance between summer and winter performance. Further north, it's not uncommon to see close to vertical mounting. This helps shed snow and ice, while maximizing the daily harvest in dark months.

Flat mounting on vans and RVs works too, but expect lower winter performance. Tilting mounts can boost output, but require you to stow the panels before moving.

Add up your daily watt-hour usage (appliances × hours), divide by average sun hours, and size your array accordingly. Example: 1000Wh daily use ÷ 4h sun = 250W panels minimum.

Ideally, you want to have more solar than you use in a day, so you can "catch up" after a couple of cloudy days.

For help, see our off-grid battery sizing guide.

It depends on your loads and how many days of backup you want.
Figure out your daily usage, then multiply for the number of days you want to run without charging.
After that it's just a matter of picking your batteries out. Our batteries are listed with their Watt hour (Wh) capacities to help make this easier.

See our article on battery sizing to help get a better understanding.

Depends. The charge controller manages charging, while the inverter is used to help you consume that charge. Either can be used independently, but usually work best in a system together.

The inverter converts DC to AC so you can run household devices. Off-grid systems use multiple components together: Solar panels + MPPT controller + Sapphire LiFePO₄ battery + Inverter.

Always include fuses or breakers, disconnect switches, and proper gauge cabling to avoid fires.

Sapphire carries battery disconnect switches and wiring accessories tested to handle high current safely.

Yes, if sized appropriately. Small systems can handle lights and USB charging, while larger arrays with multiple batteries can support appliances and full-time living. Many Sapphire customers start small and scale up as their needs grow.

Reach out to us with your goals and we can help guide you!

It varies a lot from person to person, but some general guides would suggest the following:
Vans: Usually 100–400W of panels + 100–300Ah LiFePO₄ battery.
Cabins: 400–1000W panels + 200–600Ah battery.
Sheds: 100–200W with 100Ah battery (more if you want to run tools)