Different Arrays and Charge Controllers Charging 1 Batt. Bank

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OffGridRory
OffGridRory Solar Expert Posts: 26 ✭
in Solar Beginners Corner #1
Hello again all!

I've been up and running for several months now thanks to the good folks here who have answered many questions for me. I have yet another...

I'm running (2) Evergreen 205 panels through a Morningstar MPPT 45a charge contoller to a 12v battery bank. I've aquired many other solar panels secondhand that I'd like to add to my ability to use more power during the day since I rarely use all that much power at night and the 2 existing panels top off my batteries in about 2 hours of sunshine...

The panels I have right now that I'd like to set up are 12-15 of those cheap 15w harbor freight and sunforce panels... I'd prefer to set all of these panels up through a cheap, but large amp capacity, charge controller rather than using the existing and bulky charge controllers that come with each set of 3 or 4 panels...

Can I simply run them all through another charge controller into the same battery bank? I've seen people use multiple of the same charge contoller, but I do not want to shell out another 5-600 dollars for another of the charge controllers I have since this will just be temporary and giving me the ability to use this extra potential power that is just sitting in my garage for now... (I have future plans for these panels, but it is not here)... Can I get a cheap PWM charge controller that will take all these panels, run the panels through a combiner box and to the controller that will also charge the same battery bank? I forsee issues if it is not the exact same controller since it may charge at different voltages than my MPPT one... Thus messing up when the controllers are in absorb, float etc... Is this something I should be worried about or is it possible to just forget this nonsense and hook up another charge controller?...

The second thing I will mention is these new mini-inverter's that plug into the wall and energize the grid with your extra power... Are they safe? I don't want to fry a hydro guy working on the lines because I used this cheap piece of equipment out of China... The one I was looking at recently is a 550w grid-tie inverter made by Ensurpa

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=grid+tie+inverter

I've watched a few youtube videos and people claim they are safe, albeit not that efficent.... This would be a good way for me to use my extra power during the day since I'm an "On-Grid Off-Gridder" for now... For the price, it may be the most effective way for me to use all the power these panels create during the day by pumping it all back in the grid, AND eliminate any problems I might have in plugging extra panels into another charge controller that is fed into my battery bank...

Thoughts? Thanks in advance all...

Rory
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
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    Re: Different Arrays and Charge Controllers Charging 1 Batt. Bank

    To answer your second question first: They may be safe, (but may not be either) but they certainly are not legal in any North American jurisdiction. In the event of a failure and a fire, it is quite possible that your insurance would be no good. There is none of these that are UL or CSA listed that I know of. Additionally, any grid tie of any sort requires permits, inspections and utility authorization. Since these don't carry any listings they cannot be installed into the grid legally.

    As for question number one, you can simply parallel all those HF panels together into some sort of combiner, and then install a proper sized PWM controller. You should however install a fuse (or series of them!) between each panel to do it right, so that a fault in one panel wouldn't cause a fire, but with these little HF panels, even with 12 of them I probably wouldn't worry too much about it, as the total would be only ~ 150 watts or maybe, if you are lucky ~ 8 amps.

    Tony
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