There’s nothing worse than going to start your car and getting nothing from the key turn. A dead battery can really put a crimp in your day, especially if you’re a long way from home.
An excellent solar car battery charger, like the Eco-Worthy, means you’ll never have to deal with a dead battery again.
To help you find the right solar car battery charger for you, we’ve reviewed some of the best on the market and compiled a buying guide to give you the low-down on what you should be looking for.
What are the best solar car battery charger kits to buy in 2021?
A with all our reviews, we’ve broken these down into discrete categories that highlight how useful they are in different circumstances.
1. Our top pick – ECO-WORTHY 25 Watts 12V Off-Grid Solar Kit
The Eco-Worthy kit comes with everything you need to charge your car battery using clean solar power. The waterproof 25-watt solar panel comes with a waterproof 9.84 foot SAE connector cable which is easy to connect and disconnect from the charge controller.
The USB charge controller is there to prevent your battery from overcharging, accidental discharge, and short circuits. It also includes a reversed polarity protection. The front of the charge controller has two indicators for checking the status of the charging and discharging.
In addition to its use as a car battery charger, the Eco-Worthy can provide direct DC power for pumps, fans, lights, and similar 25-watt DC appliances. It can also be used to charge RV, camper, and marine vehicle batteries.
The dimensions of the Eco-Worthy are 20.5 x 14.4 x 0.7 inches, and it weighs in at around 4.85 lbs.
What we like:
- Quick to install – The Eco-Worthy kit is designed to be quick and easy to install and use, going from packed away charging your battery in just three easy steps.
- Plenty of protection – The 3A Solar Charge Controller features over-voltage protection, low-voltage protection, and reversed polarity protection to keep your battery safe.
- Easy connections – The waterproof SAE cable provided with the kits has quick connectors to make it easier to attach it to your battery.
What we don’t like:
- Poor instructions- Several users report that the instructions sent with the Eco-Worthy kit were either illegible or partially printed in the wrong language.
The Eco-Worthy 12V Off-Grid Solar Panel is an excellent all-on-in-one kit for solar battery charging. It’s versatile enough to be helpful in various applications and simple enough to be easy to install and use.
2. The runner up – Powiser 20W 12V Solar Panel Car Battery Charger
Coming in a close second to the Eco-Worthy is the Powiser 20W 12V Solar Panel Car Battery Charger.
The one-piece panel of the Powiser is made from waterproof and dustproof ETFT plastic and is reinforced with a layer of epoxy board as the bottom plate to help prevent any panel breakages.
The included 3-piece SAE cable kit is plug-and-play. A common component, it can be used for both cars and 12V batteries. The cable comes with both carabiner and suction cup attachments to suit your installation needs. The Powiser is versatile enough to be suitable for automobiles, RVs, motorcycles, ships, and snowmobiles.
Protection for your battery is provided by an inbuilt charging microprocessor that provides overvoltage protection, overcharge protection, and short circuit protection while also preventing reverse charging.
The front of the panel has a three-light indicator, with blue showing idle mode, the red showing the board is charging, and the green showing that charging is complete.
The dimensions of the Powiser are 14.3x 13.58 x 0.79 inches, and it weighs just 1.4 lbs making it very portable.
What we like:
- Portable – Compact and lightweight, the Powiser is neatly portable, which is ideal for a car charger.
- Durable – The combination of a waterproof ETFT cover and an epoxy backboard makes the Powiser extra durable.
- Intelligent charging – The built-in microprocessor provides overvoltage protection, overcharge protection, and short circuit protection.
What we don’t like:
- Loss of suction – One of the few downsides to the Powiser is the fact that multiple users have reported that they’ve had trouble getting the suction cups to stick to anything.
The Powiser is a neat, durable, portable solar battery charger with a comprehensive intelligent charging program designed to protect your battery.
3. Best budget option – ALLPOWERS Portable Solar Panel Car Battery Charger
More of a battery maintainer than a battery charger, the Allpowers trickle battery maintainer can charge 12V batteries with the power of solar energy by creating a constant trickle of around 5-watts of energy.
The monocrystalline silicon panel is weatherproof, has dimensions of 12.6 x 5.0 x 0.12 inches, and weighs just 11.4 oz. This makes it ideal for placing somewhere small and unobtrusive, like a dashboard, and letting it slowly top up your battery.
The Allpowers trickle battery maintainer is connected to your battery using a plug-and-play SAE connector and either red and black battery clamps or a cigarette lighter socket attachment. In order to prevent reverse charging, the panel has a built-in blocking diode, so it won’t drain your battery if left connected.
What we like:
- Compact – The Allpowers trickle battery maintainer is the smallest solar panel on this list, making it ideal for portable charging.
- Easy to connect – The combination of a plug-and-play SAE connector and either red and black battery clamps or a cigarette lighter socket attachment make the charger very easy to connect to your battery.
- Reverse charging – The Allpowers comes with a built-in blocking diode to prevent reverse charging.
What we don’t like:
- Only works in direct sunlight – Unlike some of the panels on this list, which will work in cloudy or overcast conditions, the Allpowers only produces any significant amounts of power when in direct sunlight.
The Allpowers trickle battery maintainer is a great budget choice to help keep your battery in excellent condition and provide a constant trickle of extra change, just don’t expect it to bring a dead battery back to life.
4. Top-rated – Sunway Solar Car Battery Trickle Charger & Maintainer
The Sunway Solar Car Battery Trickle Charger helps keep your battery topped up with solar power by providing a constant trickle of energy. The amount of energy depends on the panel’s size and ranges from 1.5-watts to 8-watts.
The charger quickly connects and disconnects from the battery using an SAE Connector and conveniently plugs into your car’s 12-volt cigarette lighter.
Power is provided by an amorphous solar panel that works even if the weather is overcast or dull. The IP44 weatherproof design means you don’t have to worry about a few drops of rain or an errant splash of coffee. The durable ABS plastic and solar glass outer prevent the panel from getting damaged through scrapes and falls.
The front of the Sunway features a blue flashing LED charge indicator to show you when the panel is working, and it comes with a built-in blocking diode that prevents reverse charging. The bottom of the pad is fitted with suction cups for easy mounting.
What we like:
- Comes in multiple sizes – The Sunway comes in 1.5, 4, 5, and 8-watt options.
- Simple to connect – This charger makes use of your 12V cigarette lighter socket attachment to connect to your battery.
- Durable – The outer casing of the Sunway is both IP44 weatherproof and made of durable ABS plastic and solar glass.
What we don’t like:
- Won’t work below 60% battery – As with the Allpower, the Sunway is great for keeping you battery topped off, but even the manufacturers are keen to point out that it doesn’t produce enough energy to charge a 12V battery that is under 60%.
Small, durable, portable, and great for making sure your battery doesn’t run down while you sit and listen to the radio, the Sunway is an excellent trickle charger.
5. The premium choice – BigBlue 100W Portable Solar Panel Kit
The BigBlue is an efficient and convenient way to keep your devices charged while living off the grid. It has built-in intelligent charging technology that uses smart chip technology to ensure a safe flow of energy through the USB ports. This smart charging technology provides overcharging, overheating, and short circuit protection.
The BigBlue features multiple output ports, including a USB port, a QC3.0 fast-charging USB port (18W max), a DC port, and a 45W Type-C Power Delivery. These ports can be used to recharge 12V car, boat, and RV batteries and charge smartphones, laptops, tablets, and other USB-charged devices.
The whole panel can be folded into a briefcase and with a TPE rubber handle and comes with a kickstand so you can mount the board at the ideal 45° angle. The panel itself is made from water-resistant PET material. The folded dimensions of the panel are 16.5 x 14.3 x 1.9 inches, while the unfolded dimensions are 70.8 x 16.5 x 1.2 inches.
The BigBlue kit comes with the 100-watt panel and a DC-Anderson cable, DC-DC cable, battery clamps, and a 10-in-1 connector for different connection ports.
What we like:
- The number of connections – The BigBlue comes with multiple USB and DC connectors and a 10-in-1 connector for different connection ports.
- Portable – Despite its size, the BigBlue folds down into a briefcase with its own TPE rubber handle.
- Incredible power conversion – The BigBlue features monocrystalline solar panels with enhanced efficiency, quality, and reliability. These panels offer a solar conversion rate of up to 21-23%.
What we don’t like:
- Heavy and large – One of the few downsides to the BigBlue is that it weighs in at 10.48 lbs, and even folded up, it isn’t exactly portable.
If you’re going off-grid and want a portable and durable solar panel with enough power and adaptors to charge everything from your car to your smartphone, then the BigBlue is an excellent choice.
All about solar car battery kits
Now that we’ve reviewed a few of the best options on the market, let’s take a deeper dive into solar car battery chargers, what they are, how they work, and what you should look for when buying one.
What is a solar car battery charger?
Simply put, a solar charger for your car is a solar panel that converts sunlight into electricity.
When the photovoltaic cells in the panel are exposed to the sun’s solar radiation, they convert it into electricity.
Most solar panels produce direct current (DC) power, which has to be converted into alternative current (AC) power to charge most appliances. Some of the energy produced by the solar panel is lost during this process.
The good news is that most car, RV, and boat batteries store DC power, so a solar panel can be connected directly to them and used as a charger.
What type of solar charger do I need for a car?
Nearly all car chargers are what are called trickle chargers. This means they produce a low but consistent charge which is ideal for keeping your battery topped off.
It should be noted that it requires a lot more energy to restart a dead battery than it does to keep one topped off. Unless paired with a battery of their own, most solar chargers just won’t have the power to bring a dead battery back to life.
The size and type of charger will depend on the space you want to put it in. Larger solar panels like the BigBlue will need to be folded out and placed at a 45° angle for optimal exposure. Small ones like the Allpowers can be put on a dashboard.
To connect your solar charger to your car, you’ll need the correct connectors. You’ll need an SAE cable for a car, which is a cable used to charge vehicle batteries and power various automotive and motorcycle accessories. The SAE cable will then connect directly to the battery with red and black clips or the 12V cigarette lighter.
Benefits of a solar car battery kit
There are two primary benefits to using a solar charger in your car.
- The first is that you’re basically getting energy for free. Cars divert a small amount of the energy produced by the engine to charge the battery. This means the battery isn’t charging when the engine is off and is costing you money by burning petrol when the engine is on. Using a solar charger means you can charge your battery using the clean and limitless energy produced by the sun, even when your engine is off.
- The other benefit of a solar battery charger makes it less likely that you’ll be caught out with a dead battery. While a solar panel without a battery doesn’t produce enough energy to charge a flat car battery, it can maintain the battery and prevent it from running flat.
Are solar car battery kits safe to use?
Yes, as long as they have the appropriate built-in safety features to protect your battery.
When buying a solar charger, you’ll want to look out for reverse discharge protection, which uses a blocking diode to prevent the energy transferred from the panel to the battery from leaking back out again.
Without reverse discharge protection, an inactive solar panel can actually drain power from your battery.
You’ll also want to prioritize panels that have overcharge protection. A constant trickle charge can overcharge your battery, which can damage it. Overcharge protection monitors the power level in your battery and stops feeding it power when it’s fully charged.
To make sure you’ve got all the information you need, we’ve compiled some of the most frequently asked questions about solar car battery kits and answered them for you:
Are solar car battery chargers any good?
Yes, as long as you’re using them in the way they are intended to be used. If you’re expecting your solar car charger to be able to fully charge your flat battery, then you’re going to be disappointed.
If you’re looking for something that will provide a constant trickle of power to keep your battery topped off, then a solar car charger is exactly what you need.
How many solar panels does it take to charge a car battery?
This is one of those ‘how long is a piece of string’ questions. The answer depends on the car, the size of the panels, what they’re made of, and what the ambient weather conditions are.
However, it should be noted that solar panels are not there to ‘charge’ your battery as much as they are there to ‘maintain’ your battery. It’s less like plugging in your dead phone to charge and more like turning on the tap slightly to keep a somewhat leaky bath topped up.
How do you charge a car battery with a solar panel?
Thankfully, solar panels and car batteries are reasonably compatible. All you need to do is find somewhere to site your solar panel where there’s a good supply of sunlight, connect the board to your battery using an SAE cable and let it do its thing.
How long does it take a 100-watt solar panel to charge a car battery?
This depends on the ambient weather conditions, but it can range between 6 and 8 hours of direct sunlight. Amorphous solar panels will work in cloudy weather or low light conditions, but this will extend the charging time to around 12 to 14 hours.
Even a 100-watt solar panel won’t be able to charge a completely dead battery. This is because they only supply a low wattage trickle of power which is not sufficient to kick-start a dead battery.
The best solar car battery kits
Solar car chargers are an excellent way to take advantage of the clean and abundant energy produced by the sun to make sure you’re never caught with a dead battery again.
With our guide, you’ll know exactly what to expect from a solar car charger, what they can’t do, and what to look for when buying one.
If there’s a solar charger you’ve been using that you think should have made our list, we’d love to hear about it in the comments section below.