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Substitute for a solar charge controller.

tohimjob

I am looking for a DIY way to avoid expensive solar charge controllers. On a sailboat, some panels are always in the shade and running panels in series reaches high voltages near salt water. Can you use an $8 buck/boost converter with an opAmp or regulator for each panel. Would one regulator cover the range of voltages outputted by the panel through the day or would it need to switch between regulators?

  • I'm sure you can, assuming your method of combining outputs is well designed. It is just a question of what architecture is efficient for your geometry.

  • Just a thought... A large online retailer is selling a 30A version of this for $11.  It might be worth buying one to see what they are doing.  I would not really trust the 30A rating, but it's close to the same cost as the converter and OpAmp.  I'm absolutely certain that the $11 charge controller is not suitable for Marine applications.

    A simple blocking diode per output can give you a "best panel" charging circuit, but you do not get to use the power from the other panels.  If you don't use a lot of power, that might be an option.

  • My experience is the controller is the least expensive component in a system, the solar panels and batteries are a big expense.  The solar panels have a power curve the controllers attempt to keep them at the max power sweet spot. Batteries also use a 3 mode intelligent charging, trickle charge, volts charge mode, current limit mode to be nice to the batteries. 

    I'm assuming you want house (ship) power from solar rather than running a gas/diesel generator. Does it manually switchover now ? 

    Alot depends on how many panels you have, the ratings of those panels, the wiring, and if the boat's "microgrid" is desired to convert from variable DC to regulated DC (like to batteries), or variable DC to constant voltage constant freq AC.

    The converters can be a bulk converter, but it sounds like you want to build a DYI variable DC to regulated DC for each solar panel, and parallel all the little regulated DCs together  ? 

    A sketch would be very helpful.