FlexMax 80 setup?

rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
Hi everyone,
I just bought a lot of new stuff, and am about to begin putting it all together.
I currently have 6 Evergreen 180 panels, and a 800 watt wind generator. I am using batteries too, trying to go off grid. I have a 24 volt system using a Xantrex SW4024.
One of my new purchases is a new Outback Flexmax 80 charge controller. I also just bought 6 new Canadian Solar 190 panels.
How would you suggest I make that work out? I am confused about stringing the six 180's and another string of six 190's on the same charge controller, and then what do I do with the wind genny?

Suggestions? Thanks-

-Rick-

Comments

  • EcnerwalEcnerwal Solar Expert Posts: 101 ✭✭
    Re: FlexMax 80 setup?

    Specifics help.

    Does the wind generator have its own charge controller? Normally, it would/should. If so, connect that to the generator and the batteries, and ignore the solar WRT that.

    For the 12 panels, how you hook them up depends on what the Imp, Vmp and Voc (at coldest temperature in your area) are for all the panels.

    Something that smells wrong immediately is that you have ~92 amps @24V (2220 watts) worth of panels feeding into an 80 amp charge controller. You'll need a second charge controller (or to keep using one you already have, but don't mention?) for solar to keep the amperage at a reasonable value for the controller...
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    Rick,

    Come-on... How about posting the Voc/Vmp/Imp/Isc or model/name/number/pdf link of the panels. ;)

    This is the old series/parallel problem. Panels of equal current add in series. Panels of equal voltage add in parallel.

    My guess, "equal" would be within 5% of each other. If over 10% difference (voltage or current), then you start losing significant amounts of power when using a MPPT controller as there is no one optimum MPPT point.

    Regarding the wind generator, does it have an internal charge controller, or do you have to add a dump controller (or pair of dump controllers) to the battery bank?

    Normally, you would just add each charging device to the battery bank as placing them in parallel should not hurt anything.

    If you have all one vendor (like Outback controllers), you can syncronize them so that they enter/exit the various charging stages together and equalize at the same time (so I understand).

    If you have different vendors between the wind vs sun controllers--then, from my point of view--you can have issues.

    For example, you may program the Solar PV controller to equalize the battery bank, only to have the wind "dump controller" see the high battery voltage and start dumping energy. So--coordinating how you program and use the controllers is important.

    Generally, for most people wind is variable and not steady for hours/days on end--So, at first look, programing the PV controller for your "ideal" battery voltage profiles, and program the dump controller to be at the high end of the Absorb voltage range so that it only dumps when the wind has been really blowing and the bank is full. And when you equalize, you will probably have to manual initiate equalize on both sets of controllers so they don't "fight" each other.

    Those are my thoughts and what I would look at pending more information on the wind charge controller.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: FlexMax 80 setup?

    No offense, but you should figure out how to put it together before you buy it. That way you buy all the right things and none of the wrong ones.

    The charge controller's instruction book should have wiring diagrams explaining the many possibilities. Your biggest problems are mismatched panels and a wind generator. Ideally, each should have its own controller feeding a common battery bank.

    Fortunately this board has GREAT experts available! I'm not one of them. :D But those that are will be able to give you excellent advice as to the practicality of wiring different panels up (as far as I know it depends on how far apart in voltage/wattage the panels are - the bigger the difference, the bigger the problem).

    Batteries have minimum/maximum charge rates according to their amp/hr rating. How you achieve this is a function of the panel wattage/system voltage. @ 24 volts, your 6 180w panels could deliver a max charge current of 45 amps, enough for 450 amp/hrs of battery. The 6 190w is another 47.5 amps potential. As Ecnerwal says, together that exceeds the maximum capacity of the Flexmax 80 CC.

    The main thing is: what are you trying to achieve? You need to know your intended end power usage requirements first, before you can tell what your system should be.

    Most people will probably suggest you sell the wind genny if you can. :D
  • EcnerwalEcnerwal Solar Expert Posts: 101 ✭✭
    Re: FlexMax 80 setup?

    Nah, he's got it, and if the wind blows where he's at, it can help, though I note he's apparently already experienced the mechanical downsides of wind since his signature lists two 800W wind generators and his post only mentions one.

    I'm not bothering with wind because I'm in a lousy location for it regardless, and I'd need a monster (thus, expensive) tower to even get lousy wind, as I'm in mature trees with an average height of 84 feet.

    Cutting a hole for solar is bad enough - if I clearcut everything I own:
    1. I'd hate it (me like trees, though some thinning would be good)
    2. I'd still not be clear for good wind access
    3. I'd still be in a lousy wind zone because I'm not on the ridge-top.
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: FlexMax 80 setup?

    Thanks so far guys.
    Yeah, the wind blows all the freakin’ time where I live, so it really helps. I'm keeping it, because the sun is only up in the day! And yes, I only have one of my wind genny's running currently. It does NOT currently use a charge controller.

    Bill, I guess this is what I'm really asking like you stated: "My guess, "equal" would be within 5% of each other. If over 10% difference (voltage or current), then you start losing significant amounts of power when using a MPPT controller as there is no one optimum MPPT point."
    Given that, here are my panel's spec's: (Had I known to include this data up front, I would have!)

    CS6P-190 Canadian Solar 190 watt panels
    190W Power max
    28.8V Voltage at Maximum Power Vmp
    6.60A Current at Maximum Power Imp
    36.0V Open Circuit Voltage Voc
    7.33A Short Circuit Current Isc

    ES-180 Evergreen
    186.1 Power Max Watts
    25.9V Vmp
    6.95A Imp
    32.6V Voc
    7.78A Isc

    Also, I have a large bank of Trojan T-105’s setup as 24 volts.
    My vendor and I did the math before ordering the Outback, and since each panel creates less than 7 amps; 7 times twelve is 84 amps, (but less actual) and I'm sure I'll never have 100% perfect output, so it will do.
    The wind genny could be dealt with on it’s own, but if I had a separate charge controller for it, wouldn’t that interfere with the readings of the Flexmax controller?

    Thanks again-

    -Rick-
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    Hmmm... You may end up with the choice of two controllers or one controller running significantly under rated power.

    I don't know--but it is possible that the controller may simply MPPT on the higher or lower voltage string. If the lower voltage string--not too bad--at least all panels are contributing current. If the higher voltage string, then the lower voltage string might not contribute at all. Only the controller design engineer would know which behavior may happen...

    With two controllers on one battery bank--they will play together fine. The transition points between bulk/absorb/float may be offset in time--but no big problem there. Equalize would have to be started manually on both controllers.

    If both controllers are the same brand/model (i.e., Outback or Xantrex)--then they have the capability to behave as one large controller when networked together (as I understand).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: FlexMax 80 setup?
    BB. wrote: »
    Only the controller design engineer would know which behavior may happen...
    -Bill

    My suggestion would be to wire the panels in three strings with 4 panels each ( they are 18V nominal panels ).

    Each string use 2 170's and 2 190's

    The reason is the Imp of the 170's is higher than the 190's, so when run with the 190 in the same string, it will in effect have the 170's run a bit higher in the voltage as they will to match the lower current of the 190's, a win-win.

    Worse would be running like panels in the same strings and then parallel as the voltage difference would be additive as the number of panels increase, mixing the panels within a string keeps that to a minimum
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    With the stamp of "SG Approval"--you can't go wrong. 8)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    Actually, one possible correction.

    With four panels in series--you may have a problem with cold weather and Voc... The controller has max Voc of something like 150 VDC.

    You probably should just put two panels in series at a time (1 Canadian, 1 Evergreen)... Given that you are on a 24 volt battery bank--you should not have any problems.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: FlexMax 80 setup?

    Thanks guys, I agree with the 3 strings of four panels.

    Should I use staggered brands, like: can190\evr180\can190\ever180 on one string and the same for the 2 other strings, or should I use three Canadian panels on a string and then three Evergreens on another making 4 strings of 3?

    Also, If I buy a seperate charge controller for the wind genny, would I be upsetting the function of the Flex80?

    -Rick-
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    4 panel strings will not work--to high of voltage. 3 panel strings would work, but you would end up with an odd string at the end (and still have the MPPT Vmp/Imp problem).

    Voc when 77F:

    36.0V + 36.0V + 32.6V + 32.6V = 137.2 volts Voc at 77F...

    At 14F (from Xantex sizing program):

    40.4+40.4+36.6+36.6= 153.6 Voc @ 14F

    Just too high of voltage...

    However, mix of two panels per string CSI/EVG (Voc cold, Vmp hot):

    40.4+36.6 = 77 Voc @ 14F

    22.78 + 20.45 = 43.23 Vmp @ 100F ambient

    Your batteries should only need 30-31 volts max--and 2 volts for controller drop, still gives you ~10 volts of head room Vmp>31+2volts.

    The only drawback with this configuration is that you will need heavier solar panel cable to run this setup (2x as much copper)... But you will not over volt your controller on a cold day (150 VDC max--if I recall correctly for most current Outback/Xantrex controllers).

    -Bill

    PS: You can mix different brands/functional equivalents of Solar PV + Wind Dump controllers... Have you narrowed down the wind controller(s) you are looking at?

    Midnite is coming out with an MPPT wind charge controller that sound interesting (MPPT on a wind turbine can probably "recover" more power than MPPT on solar panels)... Their solarPV+wind may play well together (i.e., network together and fuction as an integrated controller).

    Outback might too--I don't know their production line that well... Jim/Crewzer or somebody else may be able to help here.

    -BB
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: FlexMax 80 setup?

    I really appreciate the effort on my issue Bill,
    So you're suggesting 6 strings of 2 mixed Canadian\Evergreen panels?

    I have a large roll of 4awg twisted cable, that should be fine right?
    It doesn't need to go too far. The distance from panels to controller\batteries would be about 25 feet.

    Thanks again for everyone's help!

    -Rick-
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    Yep--sounds good. Take a look at the Wiring Calculator to check voltage drops.

    As always, check the design details yourself--I am not an expert in this.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: FlexMax 80 setup?

    BB, it will work, even at 14F

    I selected this data sheet as it has a clear curves for various watt/meter/sq levels and VOC

    http://www.affordable-solar.com/admin/product_doc/Doc_MP1650%20with%20Cables_20070117164631.pdf


    Panels put out lower voltages as the irradiance level drops, not allot, but it is about 3-4V less ( 12V panel ) compared to 1000/wmsq the VOC is rated numbers the xantrex tool or the OP numbers specified. In the above data sheet, a 24V panel at 100 wmsq has a VOC of about 35V vs 44V for 1000 wmsq

    So Even at 14F in the morning dawn, it will be well under 150V, probably more like 125V, which I doubt in the OP's climate would be an issue. As soon as the panels have any sun, the panels will quickly warm up and the Charge Controller will also be harvesting energy, so I think its very safe 4 in a string
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    Solar Guppy,

    I am not quite sure what you are saying with that PDF link...

    At ~70 watts and 0.6kWm^2--you are looking at ~38 Volts @ 77F STC...

    4x38v= 152 volts

    That would be over the controllers never to exceed voltage... Voc for 0.1-1.0 kW/m^2 is ~38-44 volts... Isn't 4 panels in series too much (at least for this panel).

    The OP is in New Mexico (I believe)--can get pretty chilly there.

    -Bill :confused:
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 29,736 admin
    Re: FlexMax 80 setup?

    PS: I am assuming that we are working with a Off-Grid charge controller--so near zero current when the batteries are at float is certainly something that should be within the normal operating conditions.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: FlexMax 80 setup?

    So, S.G., you are suggesting 3 strings of 4 mixed Evergreen 180's and Canadian 190's?
    4 times 30+volts= 125 volts, but with mixed spec's.
    Better than 4 strings of 3 similar brand panels?

    Bill, you too like mixing the panels (Everg\Canad) per string? It sounds good helping to keep an even moderation as sun strength goes up and down.

    We have a range in Edgewood, N.M. of basically 0F as a low in Winter and 100F the high in Summer. And yes, I'm looking to go off-grid, thanks.

    -Rick-
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: FlexMax 80 setup?
    BB. wrote: »
    Solar Guppy,

    I am not quite sure what you are saying with that PDF link...
    -Bill :confused:

    BB, the graphic is a 24V, not 18V panel that the OP has, it was the variation between 100-1000 watt-meter-squared nicely graphed out that was the visual aide information

    The 34/36V number you and the OP used for VOC were at peak solar noon, not dawn. Any sunlight will heat the panels.

    For example, even on cold mornings in Florida ( last week 28F ) the panels were upto ~60F before there was 100 wmsq. I have both tempature and pyranometer logging on my arrays

    So the 34+34+36+36 you had becomes more like 30+30+32+32 adjusted for the lower light levels
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: FlexMax 80 setup?
    rickeolis wrote: »
    So, S.G., you are suggesting 3 strings of 4 mixed Evergreen 180's and Canadian 190's?
    4 times 30+volts= 125 volts, but with mixed spec's.
    Better than 4 strings of 3 similar brand panels?
    -Rick-

    Yes, its very technical why, but the vmp ( voltage maximum power ) is pretty wide on panels ( its call fill factor ), so running the Everygreens at a slightly higher voltage but lower current will match well to the 190's vmp and still get probably 98% of the rated power

    If you have all Evergreens in on string and the others in another, the Voltage difference between the two strings will be much greater and power harvest lower

    VOC is pretty meaningless except for never to exceed for the charge controller. Your operating vmp will be in the 70-90V range depending on the panel temperature
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: FlexMax 80 setup?

    That's great! I'll start planning the new layout based on this advise, and I honestly appreciate all of your input guys!

    One difference between these two brands of panels is the actual size of the cells used in them. The Canadian Solar cells are HUGE! I didn't measure them, but I think they might be 6" squares, whereas the Evergreens are 3"x4".

    -Rick-
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: FlexMax 80 setup?

    Based on input I got from Outback themselves, I've decided to run the setup as 4 strings of 3 similar brands panels

    -Rick-
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