Solar Car Battery Chargers: Best Buying Tips

Solar car battery chargers all work pretty much the same way.  A photovoltaic array converts the sun’s energy into DC electricity which is then fed through a controller to the battery.  In some ways solar powered chargers are ideal for battery charging because they are mostly hands-free, no maintenance, and they produce DC power which is what the batteries need anyway.

Solar Car Battery Chargers Advantages

The first question you have to ask yourself is what’s the advantage of using a solar car battery charger vs. a regular AC powered battery charger?

solar car battery chargers sunforce 50022

#1 – Flexibility

Because a solar unit does not require AC power, you have the flexibility to put the unit nearly anywhere it will get solar energy.  Some units don’t even require direct sunlight giving you even more flexibility.

#2 – Environmentally Friendly

Solar units generate no car battery chargers friendly to environmentenvironmentally harmful by-products and so they are very environmentally friendly or “green.”

 

Solar Car Battery Chargers Disadvantages

Are there any disadvantages when compared to AC chargers?

#1 – Solar Car Battery Chargers Are Less Efficient

Typical solar car battery chargers will be less efficient than their AC cousins and so they will take longer to charge.



#2 – Light Limitations

solar power sunSolar energy is only available in daytime, so for about half the day, no charging is possible.  Even when the sun is out a solar charger will be affected by cloud cover, humidity, and dust.

#3 – Cost

Solar chargers are more expensive than equivalently powered AC chargers even when considering that there are zero operating costs for the solar unit.  This is because AC power is generally very inexpensive and it is likely that the solar panel’ssolar power battery charger cost life span will be shorter than the time it would take for a solar charger to pay back the difference.

So really it’s up to you whether the advantages outweigh the disadvantages for your situation.  That being said, this article is about choosing a solar car battery chargers after you’ve made the decision to buy one.

Below I have listed the key specifications you need to consider when purchasing a solar unit along with an explanation and then the most common features also with explanation for each so you can compare apples to apples.

 

Key Specifications:

Let’s look first at the key specifications you need to consider when purchasing solar car battery chargers.

Battery Type:

6-12 volt batteriesYour vehicle will most likely have a 12 volt battery but, it’s possible in the case of garden tractors and classic cars, that it might have a 6 volt battery.  Be sure your charger matches your battery type.

Panel Watts:

Given that solar car battery chargers all work about the same way with some differences in efficiency between panel types, you can be sure of two things.  The more watts the charger provides, the more expensive the unit will be, and the larger the solar panels will be.

Charging Time:

Whether or not charging time is important depends on the use of the solar device.  I think it’s safe to say that solar units are best as charging time clockbattery maintainers or tenders than they are as chargers and they work better with smaller batteries than larger batteries.  So if the role of your unit will be a maintainer, then the time is not as much of a factor.  If you’re planning to use it to charge large batteries expect it to take much longer than an equivalent AC charger.

 

Solar Panel Types:

There are basically two types of solar panels used in solar car battery chargers with some more flexible options for the same types.

Thin Film:

These are also called amorphous panels and they work better in low light than other types and are more durable.  Their lifespan is much shorter than other types and their efficiency is not as good causing them to be larger for the same power.  These panels work better in high heat applications than mono-chrystalline.

Mono-chrystalline:

solar panel battery charger typesThese panels are heavier but, smaller in size than thin film of the same power.  They are more efficient than thin film and have a longer lifespan.

Flexible Mono-chrystalline:

Works like mono-chrystalline but can be bent up to 30% bend angle making it more durable and usable in more applications.

Flexible Thin Film:

These work like thin film but are peel and stick in application.

Size:

The more watts and the faster a solar charger is, the larger the solar panels have to be.  Take a look at your application, auto, RV, tractor, ATV, etc., to understand the best tradeoff between size and power.

 

Key Solar Car Battery Chargers Features

Overcharge/Discharge Protection:

solar panel discharge overcharge protectionThis is an important capability that most charger/maintainers have.  If you want to leave your device hooked up to the battery for long periods, this feature is essential to prevent battery drain or overcharging.

Extra Wire and Connectors:

If you want to use your charger in a more permanent location, extra long wire or extra wire is essential to allow you to place the solar panel in the ideal location for charging.  Having a variety of connectors will allow you to handle the charging and maintenance needs of a variety battery types.

 

Charge Controller:

Be careful when purchasing a solar charger that you are actually getting a charger and not just a solar panel and wires.  A charge controller is a small computer that turns a solar panel into a safe battery charger.  Without it overcharging or battery drain are possible which may damage your battery.

Outdoor Capability:

Not all solar car battery chargers are designed to be installed outdoors.  If your application is outdoors, make sure your choice has fully potted battery chargerthat capability referenced in its features.

Battery Conditioning:

Some of the more expensive models come with the ability to condition or desulfate your battery lengthening its life.

 

Weight:

Weight will be determined by the size of the solar panel and controller.  Make sure that if weight is a concern in your application that you pay attention to the weight of the overall system.

Warranty:

car battery charger warrantyWarranties vary greatly by manufacturer and the type of jump starter.  All other things being equal, a longer warranty may tip the balance in favor of one charger over another.

 

Top 5 Solar Panel Battery Chargers Comparison

Image
TitleSchumacher SP-200 2.4W Solar Battery MaintainerSunforce 50022 5-Watt Solar Battery Trickle ChargerBattery Tender 021-1163 5W Solar MaintainerSunforce 50033 15-Watt Solar Charging KitNOCO BLSOLAR2 Battery Life+ Black 2W Solar Battery Charger and Maintainer (2.5 Watt)NOCO BLSOLAR5 Battery Life Black 5W Solar Battery Charger and Maintainer
FeatureIt is environmentally safe
No electricity needed for operation
Amorphous technology allows charging on cloudy days
Rated for indoor and outdoor use
Complete with battery clamps and 12 Volt plug
Creates 5 watts of electricity for charging and maintaining 12-volt batteries
Works with automobile, tractor, electric fence, deer feeder, boat batteries and more
Made of durable ABS plastic and amorphous solar cells
Weatherproof amorphous panel charges in all daylight conditions-even on cloudy days
Includes 15" x 14-1/2" amorphous solar panel, 4 pre-cut holes for easy installation, 4 stainless steel screws, 9.5 ft wire, 12V DC plug, battery clamps and Quick Connect technology
Built-in 3-step microcontroller for precise charging
Waterproof and sparkproof for outdoor installations
Easy, do-it-yourself installation
Built-in temperature compensation sensor
12V nominal voltage 270 mAmps
Amorphous solar charging kit provides up to 15 Watts of clean, free, renewable power
Designed for RVs, cabins, homes, boats, back-up and remote power use and more!
Made of durable ABS plastic and amorphous solar cells
Weatherproof, durable solar panels can withstand impacts from hailstones travelling 50 miles-per-hour; amorphous solar panel works in all daylight conditions-even in the shade!
Kit includes: one 15 Watt amorphous solar panel, a 7 Amp solar charge controller, 12 ft. of wire, CLA adapter and battery clamps for easy installation
Rated at 2.5 Watt (180 milliampere); for 12 Volt lead-acid batteries
Waterproof; weather resistant solar charger for outdoor rated at IP65
Thin film technology; works well in low-light, cloudy and overcast conditions
Designed for safety; short circuit, open circuit, overheat and overcurrent
Multiple battery chemistries; safely charges wet, Gel, MF and AGM batteries
Rated at 5.0 Watt (410 milliampere); for 12 Volt lead-acid batteries
Waterproof; weather resistant solar charger for outdoor rated at IP65
Thin film technology; works well in low-light, cloudy and overcast conditions
Designed for safety; short circuit, open circuit, overheat and overcurrent
Multiple battery chemistries; safely charges wet, Gel, MF and AGM batteries
ModelSP-20050022021-116350033BLSOLAR2BLSOLAR5
Warranty5 years5 Years5 Year Limited5 Year Limited
Price$23.46$55.04$61.56$113.99$24.95$47.95
Height1.25 inch3 inch4.5 inch9.2 inch15.3 inch
Weight2.4 pound5 pound4.5 pound12.8 pound1.8 pound2.92 pound
Width13 inch17.8 inch16.5 inch0.6 inch0.6 inch
Length17 inch17.8 inch43 inch9.2 inch15.3 inch
Rating0 out of 5 stars0 out of 5 stars0 out of 5 stars0 out of 5 stars0 out of 5 stars4.5 out of 5 stars
ReviewsRead ReviewsRead ReviewsRead ReviewsRead ReviewsRead ReviewsRead Reviews
LinkMore InfoMore InfoMore InfoMore InfoMore InfoMore Info

Product prices and availability are accurate as of Jul 8 13:54:45 UTC but are subject to change. Any price and availability information displayed on the merchant site at the time of purchase will apply to the purchase of this product.

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I would love to get your opinion of this article or hear your solar battery charger story. Please take a moment to leave a comment below.

I think you can see that there is a lot more to the selection than just price.  For a comparison of popular units, please see our article Solar Panel Battery Charger Top 5 for 2013. I hope this article has been helpful in preparing you for making a buying decision for solar car battery chargers.





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Comments
  1. Craig

    Have you looked at Powerfilm amorphous (foldable) solar panels?

    http://www.powerfilmsolar.com/

    I would like to use this in a system to maintain/charge my car (honda element) battery that will run a a 37 qt ARB refrigerator (draws about 0.85 amps/hr) when I am camping and the car is off. The frig will have a new dedicated circuit (always hot) to the car battery (only one battery) as specified in the ARB manual. The frig will shut down at 12.8 volts and below to protect the battery so the car starts. I think it should run 12-16 hrs without running the car to recharge the battery (as long as I have the right battery).

    http://www.carid.com/images/arb/car-organizers/pdf/fridge-freezer-users-guide.pdf

    Wondering how I should set it up to charge the battery when I am camping (wiring from panel to battery, controller, battery type/size) and what size panel I should get.

    – I was thinking 30 watts for the panel since the frig does not use much power. Too much or too little?
    – Perhaps an optima battery – largest I get get? Or could I go with something else?
    – Can I just plug the solar panel into one of the factory 12V auxillary power outlets in the car – if so will it charge without the ignition turned on? Or would it better better to have another port installed (perhaps on the front bumper) that is connected directly to the battery? Thinking I want some convenience of not having to open hood and connect alligator clips each time I charge battery.
    – Anything else?

    Thanks,
    Craig

    • Mark Ridgeway

      Hi Craig, thanks for your question(s). I’m going to be upfront with you. We’re am not experts on the calculations needed to optimize your solar installation.
      That said, here is a thread that’s older, but has some good information that might help you. http://www.exploroz.com/Forum/Topic/47545/What_size_or_output_solar_panel_to_run_a_fridge.aspx and here’s one that should give you some food for thought on the right calculations. http://www.multipoweredproducts.com.au/pages/How-to-calculate-your-solar-power-needs-whilst-travelling%3F.html

      – I was thinking 30 watts for the panel since the frig does not use much power. Too much or too little? ***Please look at the articles we’ve provide to help you with the calculations
      – Perhaps an optima battery – largest I get get? Or could I go with something else? *** Any AGM/Deep Cycle battery should be okay. Optimas are good AGM batteries. There are specialty batteries designed for the needs of solar power, but remember you have to be able to start your car and so it’s probably better to go with an automotive battery
      – Can I just plug the solar panel into one of the factory 12V auxillary power outlets in the car – if so will it charge without the ignition turned on? Or would it better better to have another port installed (perhaps on the front bumper) that is connected directly to the battery? Thinking I want some convenience of not having to open hood and connect alligator clips each time I charge battery. ***You can plug directly into a power port. Usually the one used as a cigarette lighter goes directly to the battery.

      I’m not sure how much help this has been. I apologize if it’s not what you’re looking for. -Mark