# Charging two 12V lead-acid series batteries separately with one 12V solar panel

I am working on a senior design project and just wanted to ensure the following charge configuration would work. I have a 12V solar panel that I plan to run its' output to TWO separate PWM solar charge controllers. Despite the vehicle running off a a 24V system, I would like to charge the batteries separately. I think that I need some sort of changeover relay to alternately charge the two 12V batteries .I think I need some control for the relay . Could I use just one PWM charge controller if I employ the relay ? Do you think that my concept will be cheaper than 2 solar arrays and 2 PWM controllers? Just wanted some input from those who have more experience than me with solar energy. Thanks for the help and sorry for the rotated picture!

• Usually the charge controller is responsible for powering the load, what charge controller are you using? What is your load? What solar panel are you using? – Josh Jobin Jan 2 '16 at 19:05
• Test your charge controller with an ohmmeter. If Solar "-" and battery "-" terminals are connected together, as they are on mine, it should be obvious that this won't work. – Brian Drummond Jan 2 '16 at 19:05
• The regular charge controller is simply a single MOSFET that switches the solar cell on and off the battery, depending on its state of charge. So B- is shorted to Cell-, and B+ is periodically connected to Cell+. You'll have to disconnect the batteries from each other completely first. – tomnexus Jan 3 '16 at 1:44

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• That was our original design plan actually! Problem is the controller we were going to use runs around $170. Combine that with the price of a flexible 12V 100W solar panel, most of our$500 budget is taken! – Brandon Peter Jan 3 '16 at 13:44