Written By Car Bibles Staff
Published May. 31, 2018

Can we talk about the Sun for a moment? Yeah that’s right – the Sun, that big glowing ball of heat that fills up the sky every day? Well we want to ask just what has it done for us lately, huh?

Well, if you have a solar charger then it may have helped to keep your car battery topped up and healthy. Oh, and you know supported all life on Earth or something. But we’re mainly here to talk about solar car battery chargers today.

They can be a really useful investment, especially if you have a vehicle – classic car, RV, summer convertible, heck even a ride on lawnmower – that doesn’t see frequent driving.

A solar charger protects against battery discharge and can prolong battery life in a stationary vehicle, paying for itself many times over. So we’ve gone out and rounded up the 5 best solar chargers on the market today, which we present to you below.

Best Rated Solar Car Battery Chargers in 2020:

The first model we’re going to look at today is this product from ALLPOWERS. This is a pretty interesting design in that even though it is one of the smaller sized chargers (it is small enough to sit on the dashboard), it is also one of the most powerful on the list.

It achieves this by employing a Mono-Crystalline Silicon panel in its construction. These types of solar panels are some of the most efficient on the market right now. This high efficiency keeps the size down and the power up – it also, as a side bonus, means this device can charge more effectively in lower light situations than some other products.

On the negative side, whilst we do have reverse discharge protection in place on this model, there is no overcharge protection. That means you can’t leave it plugged in semi-permanently, instead just hook it up every now and then to top up the battery level (and keep it supervised).

It’s also not weather proof. The manufacturers state it can survive a few raindrops, but a pile of sugar can survive a few raindrops, and no one is calling a pile of sugar weatherproof. Luckily it’s small enough to fit on the dash and charge inside the vehicle, so it’s not a huge issue.

Key Features
  • Generates up to 18 Volts
  • Blocking Diode to Prevent Reverse Discharge
  • Clips & 12V Plug
Specification
  • Brand ALLPOWERS
  • Model AP-18V5W
  • Weight 12 oz
PROS

Can Attach Directly to Battery

Easily Has the Power to Charge a Typical 12-Volt Battery

Is Relatively Weather Proof…

CONS

… But Not Completely Weather Proof.

No Overcharge Protection

The tagline for this product from NOCO states that this product is “Lightweight. Compact. Efficient.”

To be fair, it’s hard to argue against any of those claims. This is indeed both lightweight (less than 2 pounds) and compact (smaller than 10 inches length & height).

Efficient is less of a nailed on claim however, as generating a somewhat measly 2.5 Watts means this device is one of the weaker on the list. Still, the film technology used is efficient in the sense that it works in low light conditions, so whilst it may take a while to truly generate a worthwhile amount to power, it is going to be working hard for you all day long, feeding off of scraps of light – a great feature if you live somewhere cloudy.

The device also has built in back current protection, preventing energy-draining out thorough the device when it is not charging (i.e. at night).

On the negative end, the cables are a little short and it’s hard to look past that pitiful 2.5-watt power. For a low-end price though (under 30 dollars) there are some useful features in this compact device.

Key Features
  • Thin Film Technology
  • Built in LED to Illustrate Operation
  • Prevents Back Current Drain at Night
Specification
  • Brand NOCO
  • Model BLSOLAR 2
  • Weight 1.8 lbs
PROS

Nice & Small

Internally Mounted

Water Proof

CONS

Short Wires

Low Power

This is a pretty interesting model from Sunway Solar, which has a price point of around 40 bucks, making it a product from well toward the higher end of the pricing spectrum.

What are you getting for that money? Well, power is one of the main features you’re picking up here – 15 volts of it, on a sunny day at least. You also get a well-designed power cable, that’s easy to change from 12-volt charger adaptor to direct connection clips.

That’s all very useful but the truly impressive feature is the built in LED light, which actively monitors the battery charge level. It blinks whilst the battery is charging, then stays solid when the charge is complete. That’s a very useful feature, and goes a long way to offsetting the fact there is no built in overcharge protection.

The unit is nice and rugged in design and also boasts a glass protector over the solar panel cells. It’s small enough to mount on the dash, but rugged enough to leave out too – just don’t get it soaking wet, it’s not fully waterproof.

It’s not cheap, but there looks to be enough features in this well designed piece of kit to justify that price tag.

Key Features
  • 15-Volt Solar Panel
  • Glass Protective Cover
  • Charging Indicator Light
Specification
  • Brand Sunway Solar
  • Model SWS-C3W001
  • Weight 1.45 lbs
PROS

Powerful 12 Volts

Really Useful Charge Indicator

CONS

No Overcharge Protection

Not Waterproof

We’ll go into it a little more below, but efficiency is definitely one of the standout features you should be looking for in your portable car battery charger. After all, the more efficient the model of charger, the faster the charge, and the less time it needs to be plugged in.

Well efficiency is certainly the name of the game with this product from Suaoki, which boasts a frankly phenomenal efficiency rate of 22.5%. Take it from us, whilst that may not seem very impressive, it is actually pretty fantastic.

One of the ways it achieves this is by having a nice big surface area, with the whole charger (including border) measuring about 16.5 Inches by 11 Inches. It is however extremely thin, which helps keep the weight down. It’s also to wide to pop onto the dash, but it is remarkably durable, and completely waterproof, so you can happily set it up outside.

It also has a built in reverse charge blocking diode, to prevent energy coming out of the battery when charge is not going in – i.e. at nighttime.

This is a really well designed product, with a lot of useful features onboard. Is there a downside? Of course there is, nothing is perfect or toothpaste would taste of steak. This model is the most expensive on the list, that’s its main downside.

Saying that though, whilst it is more expensive than the others, you will still get a little change back from a 50-dollar bill. That means you’re getting a lot of high performance solar charging for your money. 

Key Features
  • 18w Charger
  • 1.5 Meter Power Cords
  • Water Resistant & Durable Design
Specification
  • Brand Suaoki
  • Model B0722XB3VQ
  • Weight 12.2 oz
PROS

Powerful 18 Volts

High Efficiency

Very Lightweight

CONS

Large Size

High Price

We end on this product from ECO-WORTHY, and we’ve certainly left one of the best models to last. This is clearly a premium level auto battery charger, and so we have a number of useful features on this product.

First up is the power output – 12 Volts is going to be enough to trickle charge a whole host of battery types, from car mounted ones to motorcycle batteries and everything in between. Operation is easy and straight forward, with the supplied suction pads allowing you to hang it in the window of a vehicle, whilst it’s also small enough to sit on the dashboard, motorcycle seat or just about anywhere else.

A reverse diode stops energy leakage at night, whilst the supplied power cord is a handy 1.5 meters in length and can attach to your vehicle via the 12V cigarette lighter port or direct to the battery terminals with clips.

All in all, a very well designed solar charger with a lot of useful features.  A price tag of over 30 bucks makes this one of the more expensive models out there though.

Key Features
  • Lightweight
  • Shock Proof, Rust Proof, Dust Proof
  • 1.5 Meter Power Cord
Specification
  • Brand ECO-WORTHY
  • Model L02EP10BB18V-1
  • Weight 1.45 lbs
PROS

Durable Construction 

Produces 12V/10W Power

Can be Mounted Inside Vehicle

CONS

Not Waterproof

Expensive

Best Solar Car Battery Chargers Buying Guide

That then is the list of the top 5 portable car battery chargers on the market right now. Which is the best one for you however? And once you’ve got it, what is the best way to use it and ensure that it gives you a long, useful life keeping your battery topped up and healthy?

Step right this way for the answers to that, and many more questions!

How Solar Battery Chargers Work

Oh, we could give you an answer, and you know what? It would be the greatest answer to this question that –

– no we’re only joking. Here, let these science nerds explain how solar battery chargers work.

Advantages of Using Solar Car Battery Chargers

There are a number of advantages to using an auto battery charger that runs off of a solar cell, advantages such as:

  • Simplicity – These devices are very, very easy to use. A battery charger that plugs into a wall socket can supply a high level of power. That can require you tailor both the Amperage and Voltage outputs to suit your vehicle and current battery condition – and if you get it wrong, it can damage the battery. No such worries with a solar charger, as it simply doesn’t develop that level of power.
  • Prolongs Battery Life & Health – You may have read that last statement as a negative, that solar chargers are underpowered and not worth the time. They are only underpowered though if you expect too much from them. So no, they are not going to deliver the power to revive a discharged battery – you’ll need a power cord equipped model for that. They will however deliver a steady stream of low power, making them the perfect trickle style chargers to offset natural discharge and keep a healthy, well charged battery topped up long term.
  • Long Term Money Saving – They can be a little more expensive than battery chargers with power cords. However, once you’ve made that initial outlay then that’s it – no more bills. A solar charger will not be adding money onto your house electricity bill, instead it’s a one off charge for long term (free!) energy.

What Makes a Good Solar Car Battery Charger

Efficiency – The more efficient a solar charger is, the more light energy will be transferred into battery energy. That also means the less time the charger has to be out in the open, cutting down on times it can be damaged by weather or something similar. Efficiency is also important if you live in area with lots of cloud or shorter daylight hours, especially in winter. High efficiency will help make the most of whatever light energy is actually available. Efficiency of over 20% is very good by the way.

Reverse Charge Blocking Diode – This is a really useful feature to see – so useful in fact that you’ll likely find it present on all but the mot basic solar chargers. Basically, as the name may have implied, these devices require solar energy to function. There is none at night of course, so the charger stops, well, charging. A Reverse Charge Blocking Diode prevents stored energy from the battery leaking out through the charger when it is not supplying energy at night.

Power – it’s possible to see power ranges anywhere from 2 to 18 volts with these devices. The total power is really just going to give you a rough idea of charge time. Also bear in mind that overcharge protection is limited or non-existent on these types of chargers. If you want to plug in and not worry too much about overcharge, go for a lower powered model.

Size – Where are you going to keep the charger when it’s not being used? Where are you going to mount it when it is? These are not huge pieces of kit, and they don’t weigh much – the biggest on our list clocked in at about 2 Pounds. They can however be quite wide and tall as they require a good surface area to soak up as much solar energy as possible. Most will fit inside the vehicle, to charge from the safety of the car cabin. But larger ones need to sit outside, and so should be suitably durable to survive the weather or any other hazards.

Connectors & Cables – Don’t buy a charger that only has a 12-volt connector. That is a sure sign of a low-grade model, and none of the products on our list have only the one connection method. Also, bear in mind where you will be placing the charger, then make sure that the device you’re looking at has a long enough power cord to get from the charger to the car.

Best Solar Car Battery Charger FAQ:

Whilst they are relatively simple devices, just as with any product designed to be used in or on your car they are actually quite advanced pieces of kit. As such, we often get asked a few questions about these devices.

Here are some of the answers to the questions that we see most often.

Q:  Are Solar Car Battery Chargers Effective?

 They certainly are, provided you are buying them for the right purpose. As we mentioned above, don’t expect them to be charging up a dead battery. Do expect them to trickle charge a healthy battery.

Q:  What Size Solar Charger Do I Need?

It really depends on how quickly you want the charge to happen. If you live in a very sunny area, then you can hook up a more powerful solar charger for the day, come back and find that the battery is topped up. A lower powered one may take several days of trickle charging to get the battery to 100%. It really just comes down to speed and monitoring at the end of the day. If you want to plug it in and forget about it for a few days, go lower powered. If you want to blast the battery for a few hours whilst you work on the car, then we would suggest you go for more power.

Q:  How Long Should I Charge a Car Battery with a Solar Charger?

  Again, that is really going to depend on a lot of factors. The strength of the charger, the levels of sunlight in your area, the batteries size and current charge level. The good thing with solar chargers however is that they are pretty low powered – that’s why they are perfect as trickle, or maintenance, chargers. So don’t leave them on permanently, as they have no overcharge protection. But it’s unlikely you’ll do major damage if you disconnect after a few hours in the sun. Also bear in mind that there are some models that come with charge indicators, and they will tell you the batteries’ current charge level. If you want peace of mind then, consider one of those models. Related Post: Best Car Audio Batteries

Sources:

  1. Solar Cell Efficiency – Qrg Northwestern
  2. How Solar Chargers Work – How Stuff Works

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