Category: Solar 101

Source: SolarEdge Battery Data Sheet

That means you can use the entire capacity (9.7 kWh in this case) without damaging the battery.

On the other hand, lead-acid batteries have a much lower DoD of about 50%. This means you get less usable energy per charge, and they’re more prone to wear and tear over time.

Battery Usage Intensity

Probably the one that makes sense in a snap – If you rely heavily on solar to power your entire home every night, like in off-grid systems, you’re cycling the battery every single day. As a result, your battery will reach its end of life much faster…

Much like how our phones and gadgets don’t hold a charge as well after a couple of years of heavy use.

If you’re using your solar battery just as a backup for power outages or emergencies, you won’t be cycling it as often. This means fewer charges and discharges, which helps extend the battery’s longevity.

Environment

Both extremely cold and hot conditions can take a toll on your solar battery over time. At the heart of it, it’s all about chemistry.

In cold temperatures, the chemical reactions inside the battery slow down. This makes it harder for the battery to charge and release power, and over time, it can reduce the capacity.

On the flip side, excessive heat speeds up wear and tear, making the battery lose its capacity.

“I’ll just put it in the garage then…” Sure, that might work – generally speaking. But here’s the catch:

• A garage without proper insulation can drop to freezing temperatures, affecting the solar battery.
• A garage without good airflow or ventilation can cause temperatures to right too high, potentially leading to overheating.

The good news is that solar battery manufacturers often specify safe temperature ranges in their manuals. 

For example, Solar Edge outlines safe temperature ranges and even includes recommendations on where not to place solar batteries in their installation manual.

Source: SolarEdge Battery Installation Guide

So, you should be able to get a clearer idea of the best spots in your home to store your battery and what changes you can make to keep it within those optimal conditions.

Tips to Make Your Home Solar Batteries Last Longer

Yes, solar batteries don’t last forever. But there are some smart moves you can make to utilize the expected lifespan of a battery and ensure you won’t face any significant performance dips or early failures.

1. Stick to the Manufacturer’s Depth of Discharge (DoD)

As mentioned earlier, this is the percentage of its charge you can safely use before it needs recharging. Check your battery’s manual to see the recommended levels to keep wear and tear at a minimum.

2. Store Your Battery in a Place with Stable Temperatures.

Aim to store your battery in a place where temperatures are steady, ideally between 50°F and 77°F (10°C to 25°C).

Good options include a well-ventilated garage, basement, or a temperature-controlled shed. If stored outdoors, make sure it’s in a shaded area with proper airflow.

Avoid placing your battery in direct sunlight or near appliances that generate heat.

3. Monitor Battery Health Regularly.

If your battery comes with an app or monitoring system, download and set it up. Check the app routinely so you can catch any issues like unusual discharge rates or overheating.

4. Use Your Batteries Wisely.

As much as you want to run your entire home on solar power alone, doing so can put a lot of strain on your battery. If possible, try setting limits on usage. You might configure it to only power the essential appliances during the night or when the sun isn’t shining.

5. Check Your Battery’s Terminals and Cables Every Few Months. 

If you notice any dust, dirt, or corrosion, clean them gently to maintain good conductivity. Do not use solvents or any harsh chemicals, as they may be flammable and damaging to the battery.

FAQs on Solar Batteries

What Happens to a Solar Battery’s Capacity Over Time?

Just because a solar battery is rated to last up to 15 years, doesn’t mean it’ll perform with the same efficiency from year 1 all the way to year 15. In reality, solar batteries naturally lose some capacity each year and they’ll hold a little less charge over time.

And that’s because each time your battery charges and discharges, it uses a bit of its “life” – a cycle, as we call it. This cycling slowly reduces how much energy it can hold. 

For solar batteries, this capacity loss is gradual, but you might notice a difference around year 5 or so. Around year 10, a solar battery will have lost about 30% of its original capacity, leaving you with 70% working capacity.

How Do I Know if My Solar Battery is Nearing its Lifespan?

You can spot a solar battery nearing its end through a few clear signs:

• Significant reduction in storage capacity. For example, if your battery used to store enough power for your home to last through the night, but now only lasts a few hours.
• Frequent need for recharging, even under similar conditions and energy usage
• Longer charging times
• Sudden shutdowns, especially under heavy load
• Warning from the battery management system, which may indicate that the battery may need to be replaced soon.
• Physical issues, like swelling, leaks, and corrosion, which suggest internal degradation

How Many Hours Does a Fully Charged Solar Battery Last?

We’ve talked about a solar battery’s lifespan in terms of years, but how long it lasts on a single charge is another matter. How long a fully charged solar battery will last varies, depending on two primary factors:

• Battery Capacity

The battery’s capacity, usually measured in kilowatt-hours (kWh), determines how much energy it can hold. For example, a 10 kWh battery can theoretically power 10 kW of devices for one hour or 1 kW for 10 hours.

• Household Energy Use

Smaller appliances like LED bulbs, refrigerators, routers, and laptops won’t eat up much power. But if you’re also powering energy-hungry devices like microwaves, HVAC systems, or space heaters, your battery will drain much faster. Make sure to examine and calculate your energy consumption to get a better sense of your needs.

If you haven’t installed solar panels yet, maybe you’re thinking, they must be a hassle to keep clean. We’ve even heard new (and even old) homeowners say “Wait, what? You need to clean them?” (Spoiler alert: Yes, it’s necessary.) To make it perfectly clear, solar panel cleaning is not as complicated as it sounds. In fact, here’s why you don’t need to stress:

• There’s no need to call a professional (​​you can do it yourself)
• It’s quick and easy (think 20 minutes, like having a quick lunch break).
• You probably already have most of the tools you need lying around at home (saving you a trip to the nearest depot).

Do I Need to Clean My Solar Panels

Yes, you need to clean your solar panels to clear away dust, debris, dirt, grime, bird poop, pollen, and other residues that can block sunlight and prevent your panels from efficiently converting solar energy into electricity…

Because generally, less sunlight = less power generated.

Alex Beale, renowned DIY solar enthusiast and owner of FootPrint Hero, even ran his own experiment on his home panels, finding an average 8.9% increase in power output after cleaning them.

That said, solar panel cleaning is definitely worth it. You can avoid energy losses and save money, especially if electricity is pricier in your area.

How to Clean Solar Panels

Cleaning your solar panels is simple and doesn’t require any fancy equipment. A light rinse may only take about 20 minutes, but if you’ve got a lot of dust or grime, it could take closer to an hour. Here’s how to do it:

1. Prepare your tools and materials:
   • Garden hose
   • Tap Water supply
   • Soft bristle brush
   • Squeegee
   • Ladder (for roof solar panels)
2. Shut off your solar panel system to ensure safety.
3. Rinse off loose dust and dirt with your garden hose. Let the water flow gently – DO NOT use high pressure, as this may damage your panels.
4. Scrub the remaining grime with the soft bristle brush. Rub gently against the glass to avoid scratching the surface.
5. Rinse again to fully wash away any leftover dirt.
6. Use a squeegee to clear any remaining water and avoid water spots. This step isn’t strictly necessary, but it’s a good way to keep the glass clean and perfect.
   

Tips for Cleaning Solar Panels: Do’s and Don’ts

Before you jump straight into cleaning your solar panels, be aware of these do’s and don’ts. They’ll help you protect your solar panels and extend their lifespan.

DO:

• Make sure your garden hose comfortably reaches your panels.
• Follow the manufacturer’s guidelines on cleaning your solar panel system (This can help you maintain your warranty).
• Check that your cleaning materials are in good condition and free from any stuck debris or loose parts that might scratch the panel surface.

DO NOT:

• Do not use chemical solutions, coatings, detergents, or soaps. Solar panels come with specialized coatings and glass, and these can be damaged by these substances, reducing your panels’ efficiency.

(Just to share, we’ve found that the panels in the worst condition often belong to owners who’ve used these very products we’ve warned you about.)

• Do not clean your panels when it’s scorching hot outside. You don’t want to spray cold water on those hot panels as this can cause thermal shock and might crack the glass. Aim to clean in the morning when it’s cooler.

• Do not expose yourself to the blazing sun in high temperatures – it’s also a serious health risk.

Safety Considerations for DIY Solar Panel Cleaning

We considered putting safety tips in the last section’s DOs, but decided it deserved its own dedicated section – because, even though cleaning solar panels seems simple, it does come with some risks. 

After all, you’re working with an electrical setup. And if you are cleaning solar panels on roof, there’s the added concern of heights. Here are some key precautions for a safe cleaning experience:

• Before you start, ALWAYS  turn off your solar panel system. Even though solar panels aren’t as high-voltage as other electrical setups, they still carry some current.
• Set up your ladder on stable, level ground. If possible, use a ladder stabilizer to keep it steady and avoid any wobbling.
• When climbing, follow the rule we use for rooftop installations: maintain three points of contact – ideally two hands and one foot – to help you stay balanced.
• If you can, get an assistant to help you. They can hold the ladder steady, hand you tools, or spot you for safety.
• Avoid cleaning during high winds, rain, or intense heat.
• Set aside a dedicated space for your tools and supplies, away from the ladder and other walkways, to prevent tripping tripping or knocking anything over.

Look. We completely agree with UC San Diego engineers who in a study concluded that hiring someone to clean your solar panels isn’t usually worth it…

BUT – if heights make you uneasy or you simply prefer a hands-off approach, don’t hesitate to call a professional. It’s also worth checking if your installer offers regular maintenance as part of the package – and if so, take advantage of that!

How Often Should You Clean Solar Panels?

You should clean your solar panels every now and then – especially if you live in areas with high soiling loss risks. These are regions where there’s a lot of particulate matter like dust and sand, and not much rain to wash it away.

For example, based on a SolarAnywhere study, parts of the US West Coast are prone to soiling loss.

Now, if you’re one who prefers to take advice with a grain of salt and do a little digging yourself, you’ll probably come across all sorts of suggestions for cleaning frequency…

Some will say twice a year, others recommend every six months, and some people never clean their panels at all! So, what’s the real answer?

The truth is, all of these recommendations have a valid basis. Let’s peel the layers and look into these factors: 

• Geographic Location: In areas with regular rain, some people just “leave it to Mother Nature”. They get a natural rinse, and they don’t have to do the cleaning themselves.

• Landscaping: If your panels are installed far from trees, pollen, or heavy bird activity, you may get away with minimal cleaning.

• Roof Pitch: Some homeowners swear by “letting nature handle it” because of the angle of their roof (often without realizing it). Steep roofs allow rain to naturally wash panels more effectively, meaning a less frequent cleaning schedule could work fine.

So, while all these answers are valid, your own needs depend on what’s around your panels.

FAQs on Solar Panel Cleaning

What is the best tool to clean solar panels with?

The best tools to clean solar panels with are garden hose, tap water, and soft bristle brush. Even rinsing with water does the job of keeping your panel’s photovoltaic (PV) production at its peak. So, no fancy products or chemicals are needed as these can damage your panels.

How to clean solar panels from snow?

To clean snow off solar panels, allow the snow to melt and slide off naturally, guided by the panels tilt If the snow persists, use a solar panel snow rake to safely remove it – not a standard broom or shovel as these can scratch the panels.

Is there a way to clean roof-mounted solar panels automatically?

Yes, there are automatic cleaning systems built into solar panels that use solar energy to clean them. These systems gently spray water or create a stream over the panels, all controlled from inside your home. However, this option may not be budget-friendly for residential applications.

Does cleaning my solar panels void my warranty?

Cleaning your solar panels won’t void your warranty provided you follow the manufacturer’s guidelines. This is why we recommend avoiding putting specialized coating or other harsh chemicals and abrasive tools as these may accidentally damage the panels.