MorningStar TriStar 45 MPPT Solar circuit Breakers & fuses

lionheartlakes
lionheartlakes Registered Users Posts: 9
Good Evening,
I am currently upgrading my pv system with 3 x SOLARA SM7002 175 Watt in series (130vdc), controlled by a MorningStar TriStar 45 MPPT.

My question is what fuse/circuit breaker do i need from pv to controller, i have controller to battery fuse 50amp under control because it does tell u that information in instructions.

Thanks

standing alone in southwest france:confused:

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: MorningStar TriStar 45 MPPT Solar circuit Breakers & fuses

    being in series means the voltage added and the current (imp) stayed the same. here we take the imp and multiply it x1.5 and round it up to the next highest commercially available fuse or circuit breaker rating. for you the pv manufacturer may also specify a fuse rating for short circuits (isc) and you may possibly use that round up to the next commercially available fuse or cb also.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: MorningStar TriStar 45 MPPT Solar circuit Breakers & fuses

    For a single string of solar panels, you don't need and fuse/breaker if you size the wiring correctly.

    The way we do it in the us is take the maximum continuous current and multiply by 1.25 for rated circuit current. The NEC also has another 1.25x for solar margin of safety. Your panel is Imp=4.95 amps and Isc=5.4 amps (if I read my German correctly--don't bet on that :roll: ).
    Nennleistung P unter STC:175 [W]
    Max. Abweichung von P:+/-5 [%]
    Max. Systemspannung:1000 [V]
    Spannung bei Nennleistung:35,4 [V]
    Strom bei Nennleistung:4,95 [A]
    Leerlaufspannung:44,4 [V]
    Kurzschlussstrom:5,4 [A]
    So, your maximum current rating for the circuit would be:
    • 5.4 amps * 1.25 = 6.75
    • 5.4 * 1.25 * 1.25 = 8.44 amps
    You probably will use larger sized wire to reduce voltage drop from the array to the charge controller.

    If you have more than two panels in parallel, you will need a Series Protection Fuse in the leg of each string.

    Your bigger issue will be that these are fairly high voltage panels. These three panels if operated at -10C--will have a Voc=~148 VDC... That is very close to the maximum 150 VDC limit of the Morning Star controllers...

    You may be better off installing 4 panels--2 strings in series (2x panels) and then put those two string in parallel to avoid the Voc limit if you are in a cold climate.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: MorningStar TriStar 45 MPPT Solar circuit Breakers & fuses
    standing alone in southwest france
    You'll need to check French and/or EU electrical safety standards for guidance.

    For U.S. applications, if the Isc ("Kurzschlussstrom" = short circuit current) is 5.4 A, the the National Electrical Code (NEC) Article 690.8 says the maximum current (for design purposes) is 5.4 A x 125% = 6.75 A.

    If a circuit breaker and enclosure is rated for 100% continuous duty {ref 2008 NEC 690.8(B)(1) ex}, then the 125% safety factor is not required, and the next standard size up from 6.75 is OK. A 7 Adc DC-rated CBI breaker is available from MidNite Solar.

    If a regular ol' DC-rated breaker or a fuse is used, then the NEC's additonal 125% safety multiplier is required. For a 5.4 A Isc module, the rating would be 5.4 x 125% x 125% = 8.5 A. The next standard size up is 9 A, although 10 A is probably easier to find.

    As Bill indicated, the NEC also requires that the circuit voltage be adjusted for the local record low temperature. Use the module's Voc temperature coefficient to make this calculation, and then compare this adjusted value against the voltage limit specifications for the circuit breaker and charge controller.

    HTH,
    Jim / crewzer
  • lionheartlakes
    lionheartlakes Registered Users Posts: 9
    10 year temp lows

    The SOLARA SM7002 translation :D

    # Maximum power: 175 watt peak power
    # Voltage at maximum power: 35,4 V
    # Current at maximum power: 4,95 A
    # Open circuit voltage: 44,4 V
    # Short circuit current: 5,55 A



    Thanks for all your helpful information, i have checked the 10 year weather lows in my local area and the average seems to be -2, i will purchase either 9 or 10amp circuit breakers double pole protection.
    I hope that i dont have any weather extremes temps in the future - 10 plus.

    I will in the future i will buy one more panel and connect 4 panels--2 strings in series (2x panels) at the moment just spent £2000 on these upgrades (feeling the pinch in the old wallet section.)

    The guy who I purchased the controller ect, failed to mention the info u guys have, "so many can talk the talk, but how many can walk the solar walk??":confused:

    I have one more question for u guys;
    my exsiting system consist of
    3 x solar swiss 24v 150watt panels
    15 AMP SOLAR PANEL CHARGE CONTROLLER (controlling one panel)
    20 AMP SOLAR PANEL CHARGE CONTROLLER (conttrolling 2 panels)

    my battery bank is GNB absolyte 2v 1600 amp
    http://cgi.ebay.co.uk/12-VOLT-1600-AMP-HOUR-INDUSTRY-BATTERY-PACK-solar-panel_W0QQitemZ220551249943QQcmdZViewItemQQptZUK_ConsumerElectronics_Batteries_SM?hash=item3359e10017

    My question is can i connect the steca controllers and ms controller to the batteries, if so which is the best way to do it?
    The guy who sold me the equipment said it was ok but i have more confidence in your opinion.

    Thanks Nic
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 10 year temp lows

    Nic,
    Thanks for all your helpful information, i have checked the 10 year weather lows in my local area and the average seems to be -2,...
    See if you can find the record lows--average lows are not good enough.
    ...i will purchase either 9 or 10amp circuit breakers double pole protection.
    I hope that i dont have any weather extremes temps in the future - 10 plus.
    You will not need any circuit breakers in series with each solar array string if you have two or one parallel connected strings (only three or more string need a series fuse/breaker).
    I have one more question for u guys;
    my exsiting system consist of
    3 x solar swiss 24v 150watt panels
    15 AMP SOLAR PANEL CHARGE CONTROLLER (controlling one panel)
    20 AMP SOLAR PANEL CHARGE CONTROLLER (conttrolling 2 panels)
    Depending on your battery bank and solar panel configurations--you may need MPPT controllers only--or you may get away with a less expensive PWM controller (one panel and a 24 volt battery bank).
    my battery bank is GNB absolyte 2v 1600 amp
    Will your bank be 24 volt or 12 volt? How many batteries in parallel/series/etc...

    With large batteries, you should have a relatively large charge controller (solar or AC mains type). For storage, you can use a 1% rate of charge. For active cycling (used with daily loads), you should be in the 5% to 13% of 20 Hour capacity. For example, 1 battery and 12 volt bank:
    • 1,500 AH * 0.01 = 15 amps minimum
    • 1,500 AH * 0.05 = 75 amps minimum for cycling load
    • 1,500 AH * 0.13 = 195 amps recommended maximum
    (note: your AGM's can probably take even more charging current--but probably not a practical option for you anyway).

    Your three panels with MPPT charge controllers and 12 volt output would be:
    • 3*175 watt * 0.95 MPPT eff * 1/14.4 volts = 34 amps your controller
    • 1,500 AH * 0.05 min charge * 14.4 volts * 1/0.95= 1,158 watt solar array recommended minimum
    Unless your loads are very load and/or you have generator/electrical mains for AC charging--you should be looking at more solar panels and solar charge controllers anyway.

    AGM batteries are a very good battery but are senstive to over charging (probably will not be your problem, but make sure you charge controller is set for AGM/sealed battery--no equalization; and your charging voltage is appropriate for your bank).

    For your system, you will run a real chance of "deficit charging"--basically, you will probably take more energy from the bank than the solar panels can replace. I don't know how your AGM battery responds to long term operation below 75% or 50% state of charge--but most batteries will "sulfate" and loose capacity over over a few months and by the end of a year--will probably need replacing.

    Read these battery FAQ's for background on care and feeding of your battery bank:

    Deep Cycle Battery FAQ
    www.batteryfaq.org

    Normally, you would measure specific gravity to check the state of charge. You are left with measuring the battery bank's resting voltage to estimate state of charge--3 hours or so of no charging/discharging current.

    Have you looked at a Battery Monitor for your system. I believe they are really helpful for any battery bank type--but almost mandatory for AGM to estimate the state of charge at any time. Here are some suggestions for Battery Monitors that may be local to you:
    stephendv wrote: »
    With regards to battery monitors available in Europe, you can find products from:
    - Victron energy
    - Smartgauge.co.uk
    - www.studer-inno.com
    - and Xantrex
    My question is can i connect the steca controllers and ms controller to the batteries, if so which is the best way to do it?
    Make the charge controller common connections right at the battery bank/bus bar common points. That will give each controller the most accurate battery bank voltage for proper charging. Follow the manuals for recommended battery cable diameter (and keep lengths as short as practicable).

    Steca and Morning Star both make MPPT and PWM type controllers (I think)... You have to make sure your panel voltage/current matches battery bank voltage for the correct type of controller.

    PWM controllers (for optimum power transfer) need the Vmp to be around Vbatt-charging + 2 volts minimum.

    With your panels, one panel + 24 volt bank can operate with a (cheaper) PWM controller (or two panels + 48 volt bank is OK too).

    Otherwise, any 12 volt bank and your solar panels should have an MPPT type charge controller. You can read about charge controller types in these FAQ's:

    All About Charge Controllers
    Read this page about power tracking controllers
    The guy who sold me the equipment said it was ok but i have more confidence in your opinion.
    Thank you for the compliments--we all try here.

    However, make sure you understand your application--there is only so much we can guess at from behind a keyboard and screen.

    If you have questions, or something does not make sense--please ask. A 1,500 AH battery is a scary thing... Much worse than working with house hold mains power.

    A 1,500 AH 12 volt battery can output more than 10,000 amps into a dead short. Make sure that all wires/cables going into or out of (typically the positive Bus connection) are protected by appropriately rated DC fuses or circuit breakers.

    Wrapping tools with electrical tape, removing any jewelry, wearing safety glasses, etc. ... for working with a lead acid battery.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: MorningStar TriStar 45 MPPT Solar circuit Breakers & fuses

    I forgot to add--If your controller has the option for a Remote Battery Temperature Sensor--get it...

    Typically your batteries will be charged a bit faster and to a higher voltage/capacity. Charge controllers tend to overestimate the temperature of a battery bank (controllers get warm when charging) and reduce the charging voltage a bit.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lionheartlakes
    lionheartlakes Registered Users Posts: 9
    Re: 10 year temp lows

    Thanks again for the helpful information,

    Let me explain my system

    small standalone 2 bedroom house
    6x 11watt light
    65watt lcd tv
    25 watt satellite tv box
    gas boiler 75watts
    60 watt shurflo pump

    all heavy loads operate via generator

    5kva automatic start generator
    12v battery charger Sterling Pro Digital Battery Chargers 1250CED 12v 50amp
    3 x 24v 150watt solar swiss panels controlled steca 20 and 15amp
    3 x 24v 175watt solara panels controlled morningstar mppt 45amp
    GNB absolyte 6x 2v 1600 amp 12v bank
    Invertek 1000 Watt 12V Pure Sine Wave Inverter


    Thanks Nic
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 10 year temp lows
    small standalone 2 bedroom house
    6x 11watt light
    65watt lcd tv
    25 watt satellite tv box
    gas boiler 75watts
    60 watt shurflo pump
    Sounds like you got the conservation side of the equation down.

    Check the power consumption of your devices when "turned off". Things like the satellite box (and possibly the TV) can draw significant amounts of power when in standby. Having them on a switched power strip to turn them off when not in use can be a big help for an off grid system. I have a digital TV converter and it draws about the same amount of power on as off (i guess it is keeping the digital TV guide up to date).
    all heavy loads operate via generator

    5kva automatic start generator
    12v battery charger Sterling Pro Digital Battery Chargers 1250CED 12v 50amp
    3 x 24v 150watt solar swiss panels controlled steca 20 and 15amp
    3 x 24v 175watt solara panels controlled morningstar mppt 45amp
    GNB absolyte 6x 2v 1600 amp 12v bank
    Invertek 1000 Watt 12V Pure Sine Wave Inverter
    Are the Steca 20/15 amp controllers MPPT (I hope) or are they PWM... If PWM, you need to revisit them and look into MPPT--you can be missing 1/2 of your charging current into your battery bank with 24 volt panels charging a 12 volt bank through a PWM controller.

    For the genset--ideally, if you can run it at ~50% rated load--you will be pretty fuel efficient... If you operating below 20% of rated capacity, your fuel flow will still be around 50% of full power load--so you can be using several times the amount of fuel.

    In some cases, you may be better off purchasing a second small genset to run your smaller loads... For example:
    • 50 amp charger * 14.4 volts * 1/0.80 charger eff * 1/0.50 generator loading = ~1,800 watt generator
    To charge your battery bank (assuming major continuous load on genset)--you are only drawing ~900 watts from a 5kW genset--or about 20% of its rated capacity... In theory, you would be using 2.5x as much fuel to charge your battery bank with the larger genset (all things being equal--which the rarely are).

    Or, the other way would be to run a larger/second battery charger off of your larger genset and charge the bank more quickly:
    • 5,000 watt * 0.50 loading * 0.8 charger eff * 1/14.4 volt batt charge = 139 amps of charging
    Or at least a second 50 amp charger (if you are happy with the first)--it will cost you almost no extra fuel to charge the bank 2x as fast (and 1/2 the fuel).

    Once you have the battery bank mostly full (80-90% charge), you can let the solar chargers take the battery to the rest of the way full (running the genset would be a waste of fuel).

    If you can, look at getting a Kill-a-Watt meter UK version or equivalent... Measuring your varous AC loads and generator loading/fuel flow may help you better operate your system (and more cheaply too ;) ).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lionheartlakes
    lionheartlakes Registered Users Posts: 9
    record lows -16

    record lows -16 1964

    Thanks bill for your again interesting info, the only reason im using a 5kva genset is because that is the small gentset that allows auto switching, with a pre wired ats.

    http://cgi.ebay.co.uk/KIPOR-KDE6700TA-SILENT-DIESEL-GENERATOR-with-ATS-BOX_W0QQitemZ270535795703QQcmdZViewItemQQptZUK_BOI_Industrial_Tools_Generators_ET?hash=item3efd30a3f7

    my stec controllers are PWM so i will look in to buy a 2nd mppt controller prob another ms 45amp mppt. what do u recommend

    my inverter has a remote meter that shows ac watts, voc and vdc when active i will buy a temp sens for ms controller.



    your help and advice is much appreciated
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: MorningStar TriStar 45 MPPT Solar circuit Breakers & fuses

    That is a real nice looking little diesel genset.

    I like to use things efficiently... So, the mfg manual (PDF download) says it uses ~370 grams / kWH... A liter of diesel fuel is about 850 gram per Liter...

    So, if I am somewhat correct, 1/2 of 5,000 watts is 2.5 kW and the minimum fuel flow will, roughly be:
    • kWH * 370 gm/kWH * 1 Liter/850 gm = kWH * 0.435 Liter/kWH
    • 2.5 kW * 0.435 Liter/kWH = 1.1 Liter per hour (2.5 kW load)
    So, do you have any fuel usage numbers yet for your setup?

    From my minimal understanding of diesel gensets--the general recommendation is to run them at 50% rated load (or more) for long life (reduce carbon build up and reduce cylinder wall glazing)...

    The MorningStar 45 amp should be a very nice unit... I am not involved in the solar business--so others will more experience than I regarding specific MPPT controller recommendations.

    I really like a battery monitor that keeps track of the Battery's State of Charge. Many first time off-grid folks cause an early death from under charging/over discharging their battery bank (also called deficit charging).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset