What makes a good MPPT controller?

Rybren
Rybren Solar Expert Posts: 351 ✭✭
in Solar Beginners Corner #1
It seems to me that there are 5 main MPPT controllers that the folks here are using - Xantrex, Morningstar, Outback, Midnite, and Rogue. I suspect that there are also a few people using the Chinese/Taiwanese made controllers, but not overtly advertising it.

As I move forward in planning for my new system, I've been reading the manuals for the controllers in an attempt to better understand them and to try and make up my mind on which one to buy. What I've come to discover is that I really don't have a good understanding as to what makes one controller better than the other. I've seen a number of posts where folks have stated that the Classic is the best controller currently on the market and I've also seen a comment that the Outback is the best bang for the buck (I've also seen folks mention that the same person and/or team is responsible for developing both of these controllers)

So, aside from the obvious difference of whether a unit has a built-in display rather than just LEDs, what makes one of the top 5 better than the others - and what makes the Asian ones so bad?

Thanks.

Jerry
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Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #2
    Re: What makes a good MPPT controller?

    Depends to a great extent by how big a controller you need. Morningstar and Rogue make very good small capacity controllers. outback and Midnight make very good large ones.

    Tony
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  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    #3
    Re: What makes a good MPPT controller?

    Thanks Tony,

    I'm looking at a 60A Controller and am leaning toward the FM60 over the Classic Lite 150, but only because the Outback unit has the display included at roughly the same price as the Classic Lite.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #4
    Re: What makes a good MPPT controller?
    icarus wrote: »
    Depends to a great extent by how big a controller you need. Morningstar and Rogue make very good small capacity controllers. outback and Midnight make very good large ones.

    Tony

    There are also differences in the advanced configuration options offered by the different vendors and models. These can range from the common (setting voltages , current, times and temperature coefficients for different charging stages rather than just letting you select from a number of canned profiles) on the low end to allowing you to program them for wind or hydro input sources as well as just PV panels. (The Classic can do this, the Outback cannot). The ability to interconnect CCs in a way which has them actively cooperating instead of acting independently; the ability to provide full monitoring information to a computer-compatible interface. And more.

    One of the drawbacks of the Xantrex, which seems to have had solid hardware, has been that is just did not actually do what it let you tell it to do (buggy firmware.)

    All of the ones on this list seem competent in that area, they just have different capabilities.
    SMA SB 3000, old BP panels.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #5
    Re: What makes a good MPPT controller?

    Outbacks having a monitor is a viable reason for choosing them, I know the classics come with a battery temperature sensor and I don't think the Outbacks do, so that's another $20 or so...

    I don't know your system, there may be reasons to use one over the other, I choose Midnite Classic lites and will likely even use presets if this works with their Master>Slave or Follow the leader? format. I'm computer liturate and will have a computer to monitor the system.

    It will be highly desirable to set personal configurations for some types of batteries, Rolls Surette currently being discussed in other threads would be a quick example, a basic setup wouldn't work for these that need a higher than normal voltage during some stages.

    That said a charge controller will NOT monitor your system, only the charge current and voltage at the controller. If you want to monitor your system, you should look into a battery monitor, this will tell you the current going into and out of your battery. A charge controller doesn't monitor your use.

    ...and yes the people who had the Outback company sold out/resigned and then decided to start anew with Midnite, Robin (halfcrazy?) and brother boB, stop in here and contribute. Robin's history can be seen here in Evolution of the E-Panel Having also been at Trace/Xantrex, then Outback, and Midnite...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    #6
    Re: What makes a good MPPT controller?

    Thanks inetdog,

    I don't forsee a time when I will be using more than one controller, nor do I see myself ever going to micro or wind, so those features are non-players for me. I guess that for my particular needs it really comes down to the display and whether there's a "just-can't-miss-it" sale on the Classic or Outback.

    Cheers
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  • Eric L
    Eric L Solar Expert Posts: 262 ✭✭
    #7
    Re: What makes a good MPPT controller?

    The ability and sophistication of the controller's auxiliary outputs is something I would suggest looking closely at if you are trying to maximize opportunity loads. Better controllers have one or more AUX outputs that can be set to run under varying conditions such as dawn/dusk, battery state of charge, and so on. One of the AUX functions on the current Classic, for instance, lets you use nearly all the surplus power from the panels to power certain special loads (like electric hot water heaters or other resistive loads that can take varying voltage input). If you are able to put this kind of thing to use, it can amount to a very significant improvement in the ability to use your array efficiently.

    On the other hand, if you have only a clearly defined load (e.g., only recharging batteries each day), fancy AUX functions are not important.
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  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    #8
    Re: What makes a good MPPT controller?

    Photowhit:

    Thanks for the insight.
    That said a charge controller will NOT monitor your system, only the charge current and voltage at the controller. If you want to monitor your system, you should look into a battery monitor, this will tell you the current going into and out of your battery. A charge controller doesn't monitor your use.

    Yes, I do understand the difference. Thanks for the reminder.

    I really don't know my system yet either as I'm still in the planning stage; however, I can say that for the short-term (1-2 years) I only require a 12V 200AH system. Once I'm retired, I'll be spending significantly more time at my camp and fully expect the loads to grow, so I've been looking at building a system that will be overkill for my current needs but should accomodate my anticipated growth.
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  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    #9
    Re: What makes a good MPPT controller?

    Eric,

    Thanks for pointing that out. Opportunity loads are something that I hope to take advantage of.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #10
    Re: What makes a good MPPT controller?

    Regarding the Classic and the Outback Flexmax, there are many hardware feature differences, mostly in favor of the Classic. Midnite's software is not yet mature... when Midnite does implement all of their pending software features, it will be the clear choice among the controllers.

    As of today, the Outback integration is way ahead of Midnite's. For example, multiple Outback controllers work together and can coordinate the termination of Absorb by using end amps from the flexnet dc battery shunt.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • simagic
    simagic Solar Expert Posts: 100 ✭✭✭✭
    #11
    Re: What makes a good MPPT controller?

    I have and am happy with my "Blue Sky" controller.. Google it
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