How to pick a solar panel


Joined Sep 7, 2010
What do you want them for?
Of course can't just buy a panel without consideration of what battery you will be feeding . ( don't buy panels from that supplier eBay cannot be beaten) .....

A Quick factlet on panels ... the one in your link is described as "12V ...10W " But looking at the specs it has an open circuit voltage 21,5V and delivers max power when voltage is 17,8V !!! so what's going on????

This panel has been designed to connect directly to a 12V flooded lead acid battery , they can tolerate modest overcharging , the falling price of panels has made charge controllers ever more unattractive so if you are going to charge flooded lead acid this panel would be good , no expensive and vulnerable to damp charge controller needed .....

But lead acid is really stone age compared to lithum , and lithium will require circuitry between it and the panel ....

First decide on battery ...


Joined Aug 27, 2009
The open voltage and MPPT are typical for panels designed to charge 12 lead-acid battery systems with a PWM type charge controller. Never expect good lead-acid battery recharging from close to full discharge without a proper charge controller connected to a suitable wattage solar panel. Sure, with a few watt solar panel you can maintain a fully charged battery but it will not properly recharge a flat battery.

Thread Starter


Joined Nov 18, 2016
I want to use it as a power source for a "12V" battery, recharging between "11.5V" to "14.2V". The electronics are not a problem, I intend to use an "LM2596" at 150KHz, I hope its enough.