What will happen if I plug in a cheap HarborFreight 15$ Solar panel into my cigarette lighter . Yes included Are battery terminal type of clamps and the lighter plug. 15$ is cheap ! I think it’s Worth just to try it for the fun of it .

 

Probably nothing useful. When the engine is off I believe the cigarette lighter is off/disconnected so the panel would not provide a charge. When the engine is running the alternator should supply a charge far greater than anything the panel would put out. In addition, you probably need a solar panel controller to regulate the output of the panel otherwise you may cause damage.

 

For $15, it’s worth buying it and testing it. Photo Voltaic cells are used by car dealers to keep car batteries charged when on their lots. These special setups include voltage regulators. So just check the output of the Harbor Freight unit and ensure it has a regulator of around 14.4 volts or 12v. If the output is higher than 14.4, you risk damaging the car battery. A voltage regulator is a simple component to wire in to the harbor Freight unit.

 

How long are you leaving your GLK without using it? If you drive it once or twice a week the solar charger isn't necessary and if you drive it every couple of months I doubt it is enough to help.. For long term storage a battery tender, not trickle charger, is the way to go... Easy to connect and will extend the life of your battery...

 

^ Agreed. I'd just use a NOCO trickle charger. Mine cost $20 and works great.