Newbie questions: Please Read

Hello, my name is Dustin and I’m from TN. First and for most I attend school at Tennessee Technology Center at Hohenwald and my class and I received a grant from Lowes for green technology. We’ve learned a lot in this process mainly that it is very expensive. We have a “HAM SHACK” that we will be taking completely off grid. My question is for you that run the Magnum inverter, does this inverter allow you to transfer data via web?

Thank you

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,331 admin
    Re: Newbie questions: Please Read

    Magnum appears to have an open RS 485 protocol available for external connections:

    http://www.magnumenergy.com/Literature/Application%20Info/Magnum%20Networking%20Communications%20Protocol%20%282009-10-15%29.pdf

    They also say to contact them directly if you need more information.

    My question is that Magnum tends to make larger inverters (1,000 - 2,000 watts and larger)... For the most part, unless you are building a very large off-grid solar array/system (very $$$$)--Normally, you would start with your loads (conservation being the the watch-word)--and then start designing the system from there.

    Also, you should be looking at monitoring your battery bank status (battery monitor or similar). In the end, the battery is the heart of the off-grid system and you need to know its present state of charge, current going in and out, and if you need to start a genst and/or load shed to protect the battery from damage (under charging, aka deficit charging, or deep cycling below 50%--for longer life; and below 20%--avoid killing battery bank right there).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Newbie questions: Please Read

    Yes it monitors all of that including the batt status and current in and out but you must buy what’s called a mag tap.

    http://www.aprsworld.com/magtap/

    It allows you to monitor the info via internet. I didn't know that until later this morning. Yes it isn’t a large system but we have a lot of electronics that use a lot of power and sometimes there will be multiple things running at once, for weather emergencies. The room uses somewhere around 2400 watts. That is with everything up and running at once which will rarely happen although I think we could get by with around 1800W inverter we are wanting to be sure jic.
  • BB.BB. Super Moderators, Administrators Posts: 32,331 admin
    Re: Newbie questions: Please Read
    Yes it monitors all of that including the batt status and current in and out but you must buy what’s called a mag tap.

    http://www.aprsworld.com/magtap/

    It allows you to monitor the info via internet. I didn't know that until later this morning. Yes it isn’t a large system but we have a lot of electronics that use a lot of power and sometimes there will be multiple things running at once, for weather emergencies. The room uses somewhere around 2400 watts. That is with everything up and running at once which will rarely happen although I think we could get by with around 1800W inverter we are wanting to be sure jic.

    What is your expectations of power from this solar array / off grid solar system?

    I run my entire home off of a 3.5 kW grid tied system--from what little you have described--My system (if off grid) would be way to small for your power needs...

    For example, say you had 1,000 watt of solar panels around Nashville Tenn... The typical off-grid solar system, at best, is about 52% efficient. Using the PV Watts website:
    "Station Identification"
    "City:","Nashville"
    "State:","Tennessee"
    "Lat (deg N):", 36.12
    "Long (deg W):", 86.68
    "Elev (m): ", 180
    "PV System Specifications"
    "DC Rating:"," 1.0 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 0.5 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 36.1"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:"," 6.9 cents/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
    1, 3.62, 57, 3.93
    2, 4.32, 62, 4.28
    3, 5.25, 81, 5.59
    4, 5.53, 78, 5.38
    5, 5.63, 80, 5.52
    6, 5.95, 79, 5.45
    7, 5.99, 82, 5.66
    8, 5.68, 79, 5.45
    9, 5.27, 71, 4.90
    10, 5.07, 73, 5.04
    11, 3.63, 53, 3.66
    12, 3.22, 49, 3.38
    "Year", 4.93, 843, 58.17

    That is about 49 to 82 kWHrs per month of available power, or if divided by 30 days per month is roughly 1.6 to 2.7 kWH per day (average peak available 120 VAC power from solar panel through charge controller to battery to inverter to your AC load).

    A 1,000 watt solar array would just power your 1.8 kW loads for an hour or so per day... And a 1 kW off grid solar RE system is probably in the range of $5,000-$10,000 for parts and batteries alone.

    I may be missing something--but until you measure your loads (Peak Watts, average Watts, Watt*Hours per day)--it is very difficult to know what size system you are looking at.

    A very easy/quick/cheap way to log your AC kWH loads is to use a Kill-a-Watt meter. There is a DC version Amp*Hour / Watt*Hour meter like these available too.

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