Wiring diagram needed

Kefalonianman
Kefalonianman Solar Expert Posts: 60 ✭✭✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
Hello there

I need some help for I can check my Electrican is installing my equipment correctly

I have the following

Xantrex 4024
16 * 6v t105 Trojan batteries
10 solar panels label
Spec is
Soveno svt-t-185-fc1
Peak power 185w
Max peak power 189.9 w
Min peak power 185w
Voltage at peak power 26.3 v
Current at peak power 7.04a
Open circuit vol 32.7v
Short circuit current 7.92a

Xantrex 60a charge controller

I want to gain maximum amps as possible so what is the best configuration for the solar panels and batteries the panels have plug in connectors but I an thinking I need a series / parrelell configuration to gain max

I need the system to be 24v as I have two turbines as well which only work 24v

Any help with a diagram would be appreciated or a link to a site,
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Wiring diagram needed

    There's only one way to wire sixteen 6 Volt batteries for a 24 Volt system: four in series strings, four of those strings in parallel.

    Xantrex has an array sizing tool, buried somewhere on their site. http://www.se-renbu.com/support/xwsizing/Default_SE.aspx But no guarantee you can get to it directly from that link; you may have to hunt and poke. Frankly, their web site isn't very good when it comes to ease of use. :roll:

    It looks to me like the odd panel specs * ten panels limits you to two in series strings time five strings, as the Voc will go over the 150 limit of the XW controller if you put five in series (32.7 * 5 = 163.5 Volts).

    BTW, that isn't enough panel (1850 Watts) for that much battery (900 Amp hours). You might get 48 Amps from that array, which is only just 5%. Add panels or, if you can, drop batteries.
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  • Kefalonianman
    Kefalonianman Solar Expert Posts: 60 ✭✭✭✭
    #3
    Re: Wiring diagram needed
    Cariboocoot wrote: »
    There's only one way to wire sixteen 6 Volt batteries for a 24 Volt system: four in series strings, four of those strings in parallel.

    Xantrex has an array sizing tool, buried somewhere on their site. http://www.se-renbu.com/support/xwsizing/Default_SE.aspx But no guarantee you can get to it directly from that link; you may have to hunt and poke. Frankly, their web site isn't very good when it comes to ease of use. :roll:

    It looks to me like the odd panel specs * ten panels limits you to two in series strings time five strings, as the Voc will go over the 150 limit of the XW controller if you put five in series (32.7 * 5 = 163.5 Volts).

    BTW, that isn't enough panel (1850 Watts) for that much battery (900 Amp hours). You might get 48 Amps from that array, which is only just 5%. Add panels or, if you can, drop batteries.



    Many thanks for your quick reply

    I do have two turbines (700w each) and 4 smaller panels (125 w) all connected on the system as where I am good winds especially September till may
    I bought the panels from a mainstream supplier in Greece and he has told me the panels would be fine with that charge controller but did not tell me how to wire them up.

    I will study the Manuel some more

    feedback would be helpful and I think I need to contact my supplier and ask why he supplied me with something that is not correct



    Thanks for your help
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Wiring diagram needed

    It isn't wrong per se, just limited. I'm assuming the controller is the XW MPPT 60: http://www.solar-electric.com/xaxwmp60amps.html If they were figuring on two strings of five panels each it will not work because of the Voc of such an array being above the input limit of the controller. With ten panels that limits you to one other choice: five strings of two each. Each string will need its own fuse in that configuration.

    Do not count on the turbines doing much charging even if there is steady wind; they usually are over-rated on their capacity. You may also only get power from them when the panels are not putting out, so instead of supplementing the panel output they will substitute it depending on weather conditions.

    The four small panels might provide a little over 1 Amp to the mix. Probably not worthwhile including them.
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  • Kefalonianman
    Kefalonianman Solar Expert Posts: 60 ✭✭✭✭
    #5
    Re: Wiring diagram needed

    Just stratching for ideas

    If was was to only add 8 panels 4 in series (130v) and then save the other two panels and purchase 6 more when funds allow with another xantrex controller would my inverter be able to handle this xw4024 because I would have

    2 * 700w turbines
    4 * 125w panels
    8 * 185w panels

    Plus proposed
    8 * 185w panels

    Total being 4860 although the wind doesn't produce max when sun shining

    Would this be my best solution

    Also I would have to mount the other 8 panels on either sw or se roof space would they still work effectively
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Wiring diagram needed
    Kefalonianman wrote: »
    Just stratching for ideas

    If was was to only add 8 panels 4 in series (130v) and then save the other two panels and purchase 6 more when funds allow with another xantrex controller would my inverter be able to handle this xw4024

    The inverter doesn't care how many panels/turbines/batteries you have. All it wants is the right Voltage and enough Amp hours to run the loads.

    The charge controller would probably do best around 1600 Watts of array max (full potential power output, no "clipping" of excess power) so eight panels per controller is likely a better number: two strings of four in series (1480 Watts). Add another similar array and controller and you would have better charging of that 900 Amp hour bank.

    Depending on your climate/roof angle/insolation/shading, having panels facing some SE and some SW can be advantageous over all due South. For one thing you may capture more Watt hours over-all. For another not all the panels will be in full sun during the hottest part of the day; you would probably get more power out of the SE array than the SW one because of the temperature difference.

    Wind turbines need their own controllers and a dump load to put power to when the batteries are full. They have to stay "loaded" to avoid spinning free and (literally) flying apart.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #7
    Re: Wiring diagram needed

    OR, how about three strings of three panels.
    This lowers the Vin to the Charge Controller (assuming it is the XW SCC MPPT CC). The lower Vin increases the efficency of the CC, and gives you the power contribution of one more panel.

    The cost is that for three or more strings, each string needs to be protected by a fuse or breaker.

    Just an opinion, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #8
    Re: Wiring diagram needed

    Along that same line of thinking, could he just buy two more panels and run 3 strings of four panels? Just making sure my thinking is correct.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Wiring diagram needed
    Seven wrote: »
    Along that same line of thinking, could he just buy two more panels and run 3 strings of four panels? Just making sure my thinking is correct.

    The twelve panels on one controller runs the risk of exceeding the output max; it might be "clipping" current often.

    Nine panels could work, since there would need to be fuses on five rows of two anyway. Then you're only setting aside one panel. Ought to supply about 43 Amps peak by my reckoning. That's still slightly under the 5% recommended minimum, not including load consumption.

    I picked on the eight now/eight later design because of the need to up the over-all array size to handle 900 Amp hours of battery and because it's not such a good idea to run any piece of equipment at its peak all the time. Id est: a 60 Amp controller will last longer at 45 Amps than at 60 Amps. Curiously, the venerable MX60 seem to perform better at 45 Amps peak than when "maxed out".
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #10
    Re: Wiring diagram needed
    Cariboocoot wrote: »
    The twelve panels on one controller runs the risk of exceeding the output max;.

    Would you explain this in a little more detail? Output of the controller or the panels? The voltage limit of the CC is 150v right? Four of his panels at Voc would be 130.8 before derating. Running three strings would increase the amps by 50% of running two strings because amps increases in parallel strings.

    Understand I am not doubting you, I am just checking my understanding.
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  • jeffkruse
    jeffkruse Solar Expert Posts: 205 ✭✭✭
    #11
    Re: Wiring diagram needed

    4 parallel strings of batteries?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: Wiring diagram needed
    Seven wrote: »
    Would you explain this in a little more detail? Output of the controller or the panels? The voltage limit of the CC is 150v right? Four of his panels at Voc would be 130.8 before derating. Running three strings would increase the amps by 50% of running two strings because amps increases in parallel strings.

    Understand I am not doubting you, I am just checking my understanding.

    Yes; output of the controller. You can put 10 kW of panels on the input, but the output would still be 60 Amps @ Voltage. The Voc matters for the maximum V in, so four times the 32.7 Volts isn't a problem no matter how many parallel string you have: Voc remains 130.8 for the array. Extreme cold might elevate that too much, but probably not.

    So twelve 185 Watt panels = 2220 Watts. The tricky part is how efficient the conversion is; ambient temps come in to play and so does elevation, et cetera. If it were at a location with conditions similar to mine the output from that would be 61.5 in Summer, meaning some power would be "clipped" and the controller would be running at close to maximum output levels often. It's always a good idea to give yourself a little leeway. NEC has this rule about derating components to 80% for continuous duty, for instance. A bit silly for off-grid charge controllers in my opinion, because the peak current doesn't usually stay peak for long.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #13
    Re: Wiring diagram needed
    jeffkruse wrote: »
    4 parallel strings of batteries?

    That's what the man said: sixteen T105's; 6 Volt 225 Amp hours. Four in series for 24 Volt nominal, and four strings in parallel for 900 Amp hours.

    It's a lot of battery and such a configuration needs careful attention to avoid the unequal current problems inherent to parallel set-ups.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #14
    Re: Wiring diagram needed
    Cariboocoot wrote: »
    That's what the man said: sixteen T105's; 6 Volt 225 Amp hours. Four in series for 24 Volt nominal, and four strings in parallel for 900 Amp hours.

    It's a lot of battery and such a configuration needs careful attention to avoid the unequal current problems inherent to parallel set-ups.

    If your not set in stone on the batteries many here will suggest larger batteries and fewwer strings, L16's are almost twice the capacity, and are managable if just at @110lbs. Also there are single cell batteries, or a large traction battery, NAWS has most of these, though even NAWS is likely to suggest a local supplier.
    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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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #15
    Re: Wiring diagram needed
    Cariboocoot wrote: »

    So twelve 185 Watt panels = 2220 Watts. The tricky part is how efficient the conversion is; ambient temps come in to play and so does elevation, et cetera. If it were at a location with conditions similar to mine the output from that would be 61.5
    I know I should know this, but I am guessing the 61.5 is amps. How did you get that number from the 2200 w of panel? Sorry for the dumb questions,
    .
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #16
    Re: Wiring diagram needed
    Seven wrote: »
    I know I should know this, but I am guessing the 61.5 is amps. How did you get that number from the 2200 w of panel? Sorry for the dumb questions,
    .

    Watts divided by Volts = Amps
    In this case 2220 @ 82% efficiency (what I get at my place) = 1820 Watts / 29.6 charging Voltage (normal for Trojan 24 Volt) = 61.5 Amps.
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #17
    Re: Wiring diagram needed

    Ok, I wasnt derating the panel in my calcs
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  • Kefalonianman
    Kefalonianman Solar Expert Posts: 60 ✭✭✭✭
    #18
    Re: Wiring diagram needed

    Vic

    I agree with what your saying but I thinknif I put two panels aside it will make me buy 6 more therefore increasing overall output.

    Would the system be ok to run on just the 8 panels and turbines with 900 ah for now say a month while I arrange a further 6 panels to be delivered.

    Also how often should your batteries charge when the system is running and what's the usual charge time for 900ah if I charge at say 44 amps

    Paul
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #19
    Re: Wiring diagram needed

    The charge time is going to depend on how much power you draw out of the batteries and how much sun you get to put the power back. Hopefully you'll be able to complete the Bulk cycle in 2 hours, providing you haven't discharged deeply. Unfortunately it's not as linear as: used 'X' Amp hours, panels produce 'Y' Amps, 'X' / 'Y' = hours. It's that Peukart effect thing.

    When I babble about peak charge current I don't make it clear that batteries will not be charging at 90 Amps and 29.6 Volts the whole time. :blush: It's a "potential target" set of numbers which just happens to work out to allow fast recharge, full Absorb time, plus a bit of extra to compensate for loads and maybe keep the cloudy day losses to a minimum.

    Keep an eye on the specific gravity. Don't let them stay below 70% for more than a day. Recharge with generator if necessary.
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