Question on MAGNUM inverter, MMS1012.

waynefromnscanada
waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
in Solar Product Reviews & Opinions #1
Hi all, my cousin is interested in a Magnum MMS 1012 for his camp system. One of his main requirements is that the inverter not shut down whenever a bright sunny Winter day drives the battery voltage up.
I was researching the MMS 1012 and am finding two different DC input voltage listings.
In the specs, I'm finding "Input battery voltage 9 to 17 VDC".
In another place it lists "10 VDC to 15.5 VDC", which I'm afraid wouldn't be high enough for him, as his batteries are in the cold, the RTS signals the TS-MPPT-60, up goes the charge voltage and off goes the inverter.
Does anyone know for sure which operating voltage range is one is the correct one?
Thanks
Wayne
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Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Question on MAGNUM inverter, MMS1012.

    i never gave this a second thought being my voltage would not get anywhere near that high of a voltage point. i see what you are talking about and it is contradictory worthy enough for you to contact magnum itself for the right answer to it. from what i see the hbco is not 15.5v as page 33 of the manual shows the hbco to be >15.8v and, even though it's higher than what you thought, it is still not able to go to 17v as the data sheet indicates as far as i can tell. hope the confusion can get squared away to meet the requirements as it is a very nice inverter.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
    Re: Question on MAGNUM inverter, MMS1012.

    Thanks Niel, appreciate your answer. Will try to make contact with Magnum and will post if I can get an answer.
    Wayne

    EDIT: Have sent them an email. Awaiting response.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #4
    Re: Question on MAGNUM inverter, MMS1012.

    Fast response from Magnum Customer Service, PLUS I got the information I requested and more. Nice!
    "The inverter will shut down for high volts at 16vdc and start working again at 15.7vdc"
    Awesome!
    Thank you Magnum Customer Service!
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: Question on MAGNUM inverter, MMS1012.

    so will it meet your buddy's needs?

    i guess that put it as >15.8v just to allow some wiggle room even though it's at 16v.

    out of curiosity did they ever say what the 17v was about in the data sheet?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #6
    Re: Question on MAGNUM inverter, MMS1012.

    No Niel, no explanation of the 17 volts, or the other various voltages listed, including why now this latest voltage spread. I hope this latest info is correct, but one does feel a bit uneasy after sleeping on the new info, wondering which of the several is correct. If what Customer Service tells me is correct, it should work for him. If it's not right, I'll wear it, even though I'm only trying to help him out.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #7
    Re: Question on MAGNUM inverter, MMS1012.

    what is the actual voltage you think it may go to with his batteries? it is liable to be a problem for other inverters as well so maybe there's another answer to the problem too like an insulated battery box and even some electronics in there to detect voltages that high and switch in a few power resistors to heat the batteries a tad and pull down the voltage at the same time?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #8
    Re: Question on MAGNUM inverter, MMS1012.

    I'm not there on those days when the voltage is high, but tried to find out from him what the highest was, like did it reach 16? But he has no idea. Apparently he has little or no understanding of the system, even though he's retired from the telephone line maintenance business. He has just a cheap automotive type inverter there now, and it shuts down above 14.5 or so, and he can't tell me that voltage either. I had thought of 2 or 3 heavy diodes (with a manual switch to bypass them) wired in series with the inverter, but a better inverter would be far better, especially for folks that don't really understand the workings of these systems. My Xantrex Prosine 1800/12 is excellent, but they're getting hard to get.
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  • firerescue712
    firerescue712 Solar Expert Posts: 95 ✭✭
    #9
    Re: Question on MAGNUM inverter, MMS1012.

    Wayne:

    The Exeltech XP-1100 12 volt Sine wave inverter spec shows a 16.5 volt cutoff. Maybe this would work for him? NAWS has it at $561.35, which is a good price. It has many good reviews around the internet. My cheaper inverters shutoff just under 15 volts. When the sun comes out from the clouds, and the battery bank voltage is up, it sometimes shuts them off. I am looking at this inverter to alleviate this issue. Just my 2 cents.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #10
    Re: Question on MAGNUM inverter, MMS1012.

    Thanks "Firerescue", appreciate your info and will definitely check into that one as well.
    Thanks for your input, means a lot, as I'm only experienced with the inverters I have - - other than the common El-Crappo stuff of course :)
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #11
    Re: Question on MAGNUM inverter, MMS1012.

    Hey, that's nice to know for a sort of failsafe protection for batteries in AC-coupled systems.
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  • rbtrrer
    rbtrrer Registered Users Posts: 22 ✭
    #12
    Re: Question on MAGNUM inverter, MMS1012.

    Why does the controller not limit the higher voltage?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #13
    Re: Question on MAGNUM inverter, MMS1012.
    rbtrrer wrote: »
    Why does the controller not limit the higher voltage?

    In this case we're looking at the difference between the charge controller's temp compensated charging Voltage (which goes higher in cold weather) and the inverter's maximum input Voltage. Sometimes the controller will push battery Voltage up above 15, getting dangerously close to or even above the inverter's upper limit causing it to shut down. This is particularly troublesome with 12 Volt systems, less so with 24 or 48.

    BTW, even without the RTS factor, sometimes sudden shifts in insolation on panels can cause momentary system Voltage spikes which can trigger certain inverters to shut down.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #14
    Re: Question on MAGNUM inverter, MMS1012.
    rbtrrer wrote: »
    Why does the controller not limit the higher voltage?

    It should be able to limit the high voltage. But you know how tenacious those "Murphy's Lawyers" are.

    I can't place it right now but I believe there is a code requirement that there needs to be at least two mechanisms for limiting voltage when there is a source which cannot be easily turned off. - I may be mistaken.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #15
    Re: Question on MAGNUM inverter, MMS1012.
    rbtrrer wrote: »
    Why does the controller not limit the higher voltage?

    Many, or at lest some controllers will limit voltage, but if the system is in a cold winter climate, the voltage is required to go up for proper charging of cold batteries.
    It can be a choice between having the batteries properly topped up, and having the inverter shut down, or limit the voltage and not get a proper charge, but also not have the inverter shut down.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #16
    Re: Question on MAGNUM inverter, MMS1012.
    waynefromnscanada wrote: »
    Many, or at lest some controllers will limit voltage, but if the system is in a cold winter climate, the voltage is required to go up for proper charging of cold batteries.
    It can be a choice between having the batteries properly topped up, and having the inverter shut down, or limit the voltage and not get a proper charge, but also not have the inverter shut down.

    Good point Wayne. Unfortunately many voltage controlled relays do not have tempurature compensation. I just worked out some seasonal charge settings for a system without auto temp comp. Going by the manufacture's temp coefficient specs the difference between the warm and cold battery temp settings was more than 3 volts.

    Alex
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #17
    Re: Question on MAGNUM inverter, MMS1012.

    Cold weather temp compensation fools my trimetric battery monitor into thinking my charge is complete.

    For example, I set the trimetric to declare 'Batteries full' when the amps drops to 4 while the (absorb) voltage is at 29.6. In cold weather, with temp compensation, the actual absorb voltage may be 30.4. When I am late in absorb stage (amps are down to 6 or 7) if a cloud passes by, the voltage and the amps may temporarily drop to 29.8 v and 3.9 amps, and this triggers the trimetric to reset the battery state of charge to 100%.
    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    #18
    Re: Question on MAGNUM inverter, MMS1012.
    rbtrrer wrote: »
    Why does the controller not limit the higher voltage?


    If you are talking about limiting the voltage to an absolute maximum when battery temperature is low, most decent charge controllers will allow you to adjust the high limit. This is normally necessary for sealed batteries.

    boB
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #19
    Re: Question on MAGNUM inverter, MMS1012.
    SolaRevolution wrote: »
    It should be able to limit the high voltage. But you know how tenacious those "Murphy's Lawyers" are.

    I can't place it right now but I believe there is a code requirement that there needs to be at least two mechanisms for limiting voltage when there is a source which cannot be easily turned off. - I may be mistaken.

    Found it: NEC 690.72(B)(1)

    In effect: A PV system with a diversion charge controller as the sole means of battery charge regulation shall be equiped with a second independant means to prevent overcharging.

    I was thinking about the High Voltage Cut Out setting (HVCO or HVD) as a secondary protection against over charging the batteries through an AC coupled system. The wording of 690.72(B)(1) does not directly address AC coupling but I believe the intent is to protect against things going wrong with the connection to the diversion load. I was carrying this over to the regulation of the AC coupled non-battery inverters.

    Alex
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #20
    Re: Question on MAGNUM inverter, MMS1012.

    Which begs the question: why would someone use a diversion charge controller on solar?
    Normally that's what you use on turbines; which absolutely must have somewhere for the energy to go once the batteries are charged. There's better choices for PV, which produce nothing when disconnected.

    Of course the NEC tries to cover all bases.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #21
    Re: Question on MAGNUM inverter, MMS1012.
    Cariboocoot wrote: »
    Which begs the question: why would someone use a diversion charge controller on solar?

    To get regulated charging while using non-SMA equipment for AC coupling.

    Alex
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #22
    Re: Question on MAGNUM inverter, MMS1012.
    SolaRevolution wrote: »
    To get regulated charging while using non-SMA equipment for AC coupling.

    Alex

    That method becomes a whole 'nother kettle of fish.
    Not one I'd recommend, but to each their own (aspirin not included). :roll:
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