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Joel_T's avatar
Joel_T
Explorer
Feb 01, 2015

30A or 40A controller?

I’m going to mount 2 160w panels rated at 9.5 isc amps to feed 2 6v batteries…260ah. If I were to mount a 3rd panel I’m still under 30amps so a 30 amp controller should work fine….or should it. I’ve read a few places that they work better when not near their max rating. Is there any good reason to look at a 40amp SolarBoost 3024 for example that’s way more than I need for 2 panels or even 3 maybe, since there are several 30amp controllers to choose from as well. . There’s no way for the average joe to know why one’s better than another. (After seeing bazillion paged threads debating MPPT vs PWM, if those in the know don’t really know, I’m opting for MPPT for vague reasons, since I’m not an electronics nerd.)
  • JiminDenver's avatar
    JiminDenver
    Explorer II
    Feb 01, 2015
    Personally I would start out with an inexpensive 30a PWM controller with the features to support your batteries. That way if you never need to upgrade you haven't spent hundreds on a fancy controller you will never need. Should you decide to upgrade in the future you would only be out the $30-50 a useable PWM controller cost.

    MPPT isn't going to net you as much as a third panel would for the price difference.
  • 2oldman's avatar
    2oldman
    Explorer II
    Feb 01, 2015
    Joel_T wrote:
    There’s no way for the average joe to know why one’s better than another.
    There's an almost sure-fire way: price.

    The 30 will be fine until you add a 4th panel.

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