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?
#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 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
#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’s lifespan 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 an explanation for each so you can compare apples to apples.
Let’s look first at the key specifications you need to consider when purchasing solar car battery chargers.
Your 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.
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.
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 battery 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.
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.
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.
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
This 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.
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.
Some of the more expensive models come with the ability to condition or desulfate your battery lengthening its life.
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.
Solar Panel Battery Chargers
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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. I hope this article has been helpful in preparing you for making a buying decision for solar car battery chargers.