Help with two epever mppt ,two mt50 and one rj45 cable

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macoveimc
macoveimc Registered Users Posts: 1 ✭
in General Solar Power Topics #1
Hi guys, I'm new to the forum. please help me with some advice in the following situation. They have a solar installation of 1240w, mono panels 4x310w, a mppt 4210AN epever, device mt50,2000w 24vdc pure self inverter solartronics and 4 trojan t105re battery bank. The whole installation is mounted in the garage less mt50 which is mounted in the house for monitoring in time real. Now I have added another 4x200w mono panels installation, an epever 3210AN and an mt50 device. I want to mount this 50 mt in the house next to the other one, only there is only one rj45 cable that is occupied with the first mt50 and I don't have the possibility to bring an rj45 cable for the second mt50 as well. Does anyone know if I can split the rj45 cable to send a signal from both mppt to both mt50 only on a single rj45 cable. that is, to use 4 wires for one mt50 from the first mppt and 4 wires on the other mt50 from the second mppt. does anyone know the configuration of the pins that mt50. do you use all 8 wires of the rj45 cable? or a part. thank you and I hope I didn't upset you with my long story
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    Welcome to the forum Macoveimc.

    No problem with the long post/lots of photos. Very nice to see other installations in detail.

    I believe the short answer is NO, you must run a seperate cable to each MT50 remote meter... From this manual (if this is for your meters) on page 29:

    https://www.epsolarpv.com/upload/file/1903/MT50-SMS-EL-V2.1.pdf

    They use all of the cable connections. You would need, at least, 4 data connections and 2 power +/- connections for a second meter (6 connections total)--You possible could connect the second meter to the first power pins and get to to +4 new data connections and drop one pair of +/- power connections...

    But you do run the risk of damage to either the charge controller or the MT50(s) as we don't know how the RJ connections are wired inside the various devices.

    Regarding the rest of the installation--I would humbly suggest that your battery bank is a bit on the "small" side at 24 volts @ 225 AH capacity...

    For a 2,000 Watt AC inverter, I would be suggesting a 400-800 AH @ 24 volt battery bank (400 AH minimum). A good rule of thumb is (for 24 VDC battery bus) is a minimum of 100 AH for every 500 Watt of AC inverter (and solar array). 2,000 Watt inverter => 400 AH minimum battery bank.
     
    I guess you are somewhere around Bucharest, Romania? That looks like a Greek flag in one photo and Romanian colors in another photo?

    You probably do not get a lot of winter sun in Romania:
    http://www.solarelectricityhandbook.com/solar-irradiance.html

    Bucuresti
    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 46° angle:
    (For best year-round performance)

    JanFebMarAprMayJun
    2.85
         		3.48
         		4.15
         		4.44
         		5.05
         		5.21
     
    JulAugSepOctNovDec
    5.33
         		5.32
         		4.72
         		3.71
         		2.67
         		2.12
     
    So having a larger solar array is going to be very helpful for you, especially in winter (less genset runtime and less fuel usage).

    On other safety concern... I cannot tell if the wall behind the electronics and the floor of the room are non-combustible (fire resistant) or not... It is good practice to have your wiring and battery bank on fire resistant materials (i.e., ceramic tile floor, concrete or dry wall board, etc.).

    With the open wood frame/wall construction, it is very easy for a small fire to take hold and cause great damage/risk of life for you and your family/friends.

    Even though plastics used for electrical systems (conduit, wire trays, etc.) are supposed to be flame resistant--Most plastics (even fire rated plastics) will burn quite nicely with a source of heat (short circuited wiring, etc.).

    Solar power systems are running 24x7 when you are there or not--You want your system to be as safe as practical--You don't want melted/burning plastics to run down the wood walls and land on a wood/flammable floor.

    Take care,
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #3
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    Nice that Bill found a 'pin out' for your meter. I would have thought typically you could with a common battery. I'm surprised they use all of the pins.

    While I agree that the battery bank might be on the small size, I find it's often needed to start some motors/compressors in that size system, just be aware of your loads and the idle load of the inverter. Have you done a load calculation? Looks like you are adding to a current system, I think that adding array and using the batteries until they won't function before perhaps replacing with a larger battery bank is a smart way to go!


    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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