The 12V Solar Battery Charger

The 12V solar battery charger is the most popular solar battery charger because 12 Volt batteries are the de-facto standard voltage for RVs, marine boats and yachts and cars. Augmented with a solar inverter, the solar 12 V charger can support small AC loads for remote locations and for AC power back up

What is a 12V solar battery charger?

A solar battery charger converts sun radiation (photons) into 12 Volt DC power (electrons) by using the photovoltaic effect. Down to earth, it is a solar panel rated to deliver nominally 12 V. Since solar panels voltage output varies with current drawn from them and with temperature and the battery voltage decreases as the battery discharges, it is advisable to use a charge controller in between the solar battery charger and the battery. Some people might want to get AC power in times the charger is not used for charging the batteries; these people add a solar inverter.
The combination of a battery, solar panel, battery charger and inverter is a miniature version of a larger scale off grid solar power system, well documented in my off grid solar systems page

Sizes And Prices of 12 Volt Solar Battery Chargers

12 Volt solar battery chargers come in different sizes for different usage models.

The smallest can provide the trickle current that is needed balance the current drain of the battery under no load conditions. These are really battery charge maintainers, they are rated lower than 5 Watts, and the prices are typically under $50. Usually, they are small in size and can be plugged onto the cigarette lighter socket.
Medium size chargers, are chargers that can deliver at least 15 Watts of 12V DC power. These devices can deliver over 1 Ampere of charging current, roughly 1 Ampere per 15 Watts. The bigger the charger, the more charging current it can deliver and the shorter will be the time to charge the battery. Prices, for a charger employing thin film flexible panel that can be folded are around $15 per Watt.
Larger size than 60 Watts (more than 5 Ampere charging capability) are really a backup solar power generator

Desired features of 12 Volt Solar Battery Chargers

Regardless of size look for the following features:

Works under severe weather conditions
Waterproof
Shock resistant
Rust resistant
Equipped with reverse charge protection (a protection diode)
Equipped with overcharge protection
Comes with battery clamps, wiring kit and cigarette lighter plug
Has status light on its panel

Solar Panels for 12V solar battery charger

Most solar panels are either amorphous Silicon, or CIGS (Copper Indium Gallium di-Selenide). The CIGS (Copper Indium Gallium di-Selenide) is a more expensive material than the amorphous Silicon and apparently more efficient. (more juice for the per area)

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