I want to add some panels to a system.
I currently have 6 panels, 125 watt, 18 volt approximately 7 amps a piece. I wired them in series to make 3 panels, 36 volt, 250 watt, with 3 breakers in my combiner box. I have an MX 60 Outback MPPT controller and a 12 volt battery bank.
Now I would like to add another panel perhaps a newer single 250 or 280 panel and add another breaker to my combiner box.
How close do I have to match the voltage of the new panel to the other 3 that are 36 volts? Then I'm going to need some advice on my charge controller.
Thanks
Steve
Submitted
13 years 5 months ago
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Hi Steve,
That's a great question! I think you already figured out the answer. The voltage of the different strings should be as close as possible, otherwise it will either harm the system or you will lose some energy.
I'd say, try to find a solar panel at 250W (+/- 5W), 36V (+/- 2V), 7A (+/- 0.5A) or buy the exact same panels that you used.
You can connect up to 1000W to the same MPPT 60 charge controller. Let us know how you proceed and share some pictures.
I'm not sure whether you can buy a 250W solar panel in singles.
You can also consider buying couple of new solar panels with a new charge controller.