Charge controller choice.

mdm1
mdm1 Registered Users Posts: 7 ✭
in Solar Beginners Corner #1
Hi everyone! I am new to this forum but do have some experience with solar. Here is my question and problem. I have a 260 w 12v system for my cabin. It has a 18oow charger inverter with a Bz mppt charge controller. Yes the weak link is the controller. In the cold weather the float level goes up to 16v+. I have had the controller redone by Frank at BZ but still have the problem. What would you recommend for a charge controller keeping in mind my situation? My cabin does not get used much in the winter but does in the summer. My panels are right outside the cabin and face south with nothing to block the sun. I am looking for a viable solution. Any help would be great. Oh I live in WI so it does get very cold. Thanks Mike
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #2
    Re: Charge controller choice.

    For very cold batteries - say at zero degrees F, the float will be higher, but 16 is a more than a bit excessive. It should be around 2.3 volts per cell at a battery temperature of zero - or around 13.8 to 13.9.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #3
    Re: Charge controller choice.

    Toss the BZ in the recycle bin. I would seriously consider the Rogue 3024 MPPT controller. Not too expensive, great user interface, and good temperature compensation. It also gives you some headroom for room to grow.

    I believe that Morningstar makes a nice 15 amp MPPT controller as well.

    Tony

    PS. Welcome to the forum. There are some very smart folks here who have quite literally forgotten more about PV than most of us will ever know.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Charge controller choice.

    mdm1;

    Now is a good time to think about any future expansion you might want to do. Since you have to replace the controller anyway.

    If you stay with something around 15 Amps you won't be able to add more capacity later without buying yet another controller. So take the time to evaluate if your system really meets your present needs and if you might want more power in the future. For instance, you might use the place weekends only now but will you be there months at a time or even year-round later? If so, you may be looking at powering an electric refrigerator or such.

    The Rogue Tony (:D) mentioned is a very good unit, but it too has limitations for current and input Voltage. Whereas Morningstar, Outback, and Xantrex make MPPT controllers that will handle 60 Amps output and up to 150 Volts in.

    But if you only need your 260 Watts or budget is a problem (when isn't it?) you could stay with a PWM controller like this one: http://www.solar-electric.com/pros15solcha.html

    (Take a look at the whole Morningstar selection, as there are several which would fit the bill at various budget levels. http://www.solar-electric.com/mochco.html )
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
    Re: Charge controller choice.

    Marc,

    The point being, that to use a 50+ amp controller for 230 watts of panel is way over kill, price considerations not withstanding.

    The Rogue 3024 will handle 30 amps which at 12vdc is ~ 400 watts of PV, more in a warmer climate. I run the Rogue with 400 watts, and I see currents in the 20 amp range. I could add another 100 watts and only rarely would it clip excess current.

    Tony
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Charge controller choice.
    icarus wrote: »
    Marc,

    The point being, that to use a 50+ amp controller for 230 watts of panel is way over kill, price considerations not withstanding.

    The Rogue 3024 will handle 30 amps which at 12vdc is ~ 400 watts of PV, more in a warmer climate. I run the Rogue with 400 watts, and I see currents in the 20 amp range. I could add another 100 watts and only rarely would it clip excess current.

    Tony

    Tony, you missed the part about "future expansion". It's a question of how much if any expansion he's planning. Naturally if he's sticking with 260 Watts or only going up to 400 there's no need to buy a controller that will do 80 Amps @ 48 Volts. :roll: (Although people do. Why? :confused:)

    That's why I mention the smaller Morningstar PWM as well. It's just that at this point he needs to evaluate future needs that might arise. How big might they be? Answer that question and you have the info you need to pick the controller now. Like putting in larger wire than you need to begin with, just in case there's more panels in your future. :D
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  • mdm1
    mdm1 Registered Users Posts: 7 ✭
    #7
    Re: Charge controller choice.

    Thanks for all the suggestions. I think at this point a Morningstar pro star 30 amps or a Rogue 3024 are my best choices. As far as expansion goes the most if ever would be to double my panels, but I am happy with my output. But expansion is to be considered. Thanks Mike
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #8
    Re: Charge controller choice.
    Windsun wrote: »
    For very cold batteries - say at zero degrees F, the float will be higher, but 16 is a more than a bit excessive. It should be around 2.3 volts per cell at a battery temperature of zero - or around 13.8 to 13.9.

    I know, that for AZ, Flagstaff can get cold. But in MN/WI we do not consider 0°F "very" cold. Here, -30°F is very cold. In the 1990s there was a stretch of cold where Embarass MN (aptly named) recorded -60°F (that's ambient, not wind chill.) That's extremely cold even by our standards.

    The float voltage for my batteries (see sig) at 0°F is 14.6V. At -30°F it is 15.1V.

    Having made that point, the BZ controller is still crap.

    K
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  • mdm1
    mdm1 Registered Users Posts: 7 ✭
    #9
    Re: Charge controller choice.

    I purchased a Morningstar PS-30 controller. The Roque did look good also but the Morningstar I think will fit my needs for now and I can double my system if needed. I asked about the BZ and again no complaints everyone loves it I was told. Maybe in warm weather. It will be a couple of weeks before I get it installed will let you know.Thanks again. Mike
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #10
    Re: Charge controller choice.
    mdm1 wrote: »
    I purchased a Morningstar PS-30 controller. The Roque did look good also but the Morningstar I think will fit my needs for now and I can double my system if needed. I asked about the BZ and again no complaints everyone loves it I was told. Maybe in warm weather. It will be a couple of weeks before I get it installed will let you know.Thanks again. Mike

    I would be curious about who told you that - our experience, and that of several users, has been different.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #11
    Re: Charge controller choice.

    Do a search on this site and look at BZ complaints/evaluations. I know that several people who are well educated and well equipped (Solar Guppy being one that I remember)
    have done some pretty exhaustive testing on these units and have concluded across the board, that these things are POS!

    With out any other verification, the unit that I have, instead of giving some MPPT gain, actually had lower output than no controller at all!

    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,631 admin
    #12
    Re: Charge controller choice.

    Use google to search the forum... Short word searches don't work well using the forum search:

    Google: BZ site:wind-sun.com

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mdm1
    mdm1 Registered Users Posts: 7 ✭
    #13
    Re: Charge controller choice.

    Here we go again! I know I must be stupid but here is what has transpired. In all fairness-I called Frank at BZ and explained my problem was happening again. Here is what is going to happen. He is going to send me a MPPt500 to replace my 250. He said I should rewire my 12v panels in series for 24v but my system will still be 12v. Since this is my cabin and I don't use it much in the winter I really don't have much to lose. My concern is if I enlarge my system will have to buy 2 panels. I would enlarge my battery band first though. I will let you know what happens. Mike
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #14
    Re: Charge controller choice.

    congratulations in getting a bigger piece of junk. you will now have to worry if your batteries will be ok by the time you get there next. when that one fails to work properly are you going to go for round 3?
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #15
    Re: Charge controller choice.

    If Neil sounds flippant,, he isn't. The very real world experience with BZ controllers is not good. Not only not good,, but bad. Buyer beware!

    Tony
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #16
    Re: Charge controller choice.

    I seem to recall one fellow had two of those BZ 500's in a row: brand new out of the box neither one worked.

    I wouldn't risk my batteries on one.
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  • 54d18
    54d18 Solar Expert Posts: 81 ✭✭✭
    #17
    Re: Charge controller choice.

    MDM1, I currently have the Rogue 3024 with 490w of solar @ 24v
    and a 12v battery bank of 900 AH with an inverter of 1750w.

    I frequently see the max of 30A out to the battery bank and the
    controller seems very strong, in fact, for me, so far it is bullet proof.
    My brother also has one, we are both in Northern Ont. Canada, and
    we use our cabins in extreme winter conditions, with no issues.

    My take on expanding is simply that if I do decide to expand, although
    not likely, I would add another Rogue 3024, the cost would be about
    the same, without having all your eggs in one basket so to speak.

    Just my take...
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  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #18
    Re: Charge controller choice.

    "congratulations in getting a bigger piece of junk."

    I know nothing of the BZ line 'cept what I've read here.

    I do know funny when I see it and this sir made coffee shoot from my nose....
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #19
    Re: Charge controller choice.

    i'm glad somebody saw humor in that, but i was being too brutally blunt as i was too tired when i posted that. it does ring true and was not meant in any bad way toward you. it just irked me to know they are doing this to you.
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  • mdm1
    mdm1 Registered Users Posts: 7 ✭
    #20
    Re: Charge controller choice.

    Thanks for all the insults to my brain function.
    note that no insult to you was given by me, but i was critical of the product and i wondered what you were going to do when it fails for a 3rd time. if you are feeling dumb that is on you and you already indicated in a previous post that you might be for allowing them to give you that cc. niel

    quoted from you, "Here we go again! I know I must be stupid but here is what has transpired."

    In the back of my mind I knew I would be putting in something else but what can I say. My big problem is if something is going to work for 12v it should. As someone said maybe everyone thinks the way these work is how it is. I am going to my cabin Sunday and going to rewire and see what happens. Life is choices. Mike
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  • XRinger
    XRinger Solar Expert Posts: 529 ✭✭✭
    #21
    Re: Charge controller choice.

    Morningstar makes a good product. I got the TriStar 45 to use with my 500w PV,
    (using 48v) and so far it's working very well. It looks to be very well made. High quality.

    I'm using an old laptop to monitor & tweak it's operation right now, but after
    Dec 25, I should be using a new LCD display, plus a battery temperature sensor.


    Happy Holidays,
    Rich
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  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #22
    Re: Charge controller choice.

    mdm1,

    My reply was not aimed at you in any way. Neil's statement there was reminescent of my pop saying something like that to me before he tapped me in the back of the head for it. Therefore it jerked a nasal response causing me to expel coffee onto my keyboard.

    As far as brain function goes, if your worst flaw is trusting a manufacturer to make an as advertised product you are miles ahead of me in competency.

    The Rogue is an excellent product. I'm sure you could be happy with it. Looking back now I wish it was a little larger and I'll need two. This stems from another of my fubar decisions
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  • mdm1
    mdm1 Registered Users Posts: 7 ✭
    #23
    Re: Charge controller choice.

    I do believe I will be installing a Morningstar or Roque in the future. I checked my battery pack and everything was fine and the float was 14.1. Downside-I rewired the panels in series for 24v and got no reading on the charge controller. I checked the panels and they were putting out 25v. Rewired back to parallel and they read 17.5-19v and the pack was getting charged. Frank at BZ has been very good at service but maybe he has a lot of it to do. Mike
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  • dagr51
    dagr51 Solar Expert Posts: 72 ✭✭✭✭
    #24
    Re: Charge controller choice.

    "Frank at BZ has been very good at service but maybe he has a lot of it to do. Mike"


    That was a very polite indictment. I liked it!;)
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