I bought these two solar panels to charge my batteries in case of a power failure in the winter. I live in a townhouse and I am not able to install these solar panels. Solar panels have a useful life of about 25 years and these are made in 2011 , so are 9 years old. They still produce a lot of voltage, more than 21 volts in full sunlight, and have to be used with a solar controller to bring the voltage down to the correct charging voltage. If you buy both ($60 each) at the same time, I will give you a solar controller for free. Good for these two panels. If interested, please email me your name and phone number and I will call you.