Wiring up a Morningstar Suresine 300

Interlude
Interlude Registered Users Posts: 8 ✭
in Solar Beginners Corner #1
I've decided to build a small battery backup system for power outages to run lights and whatnot when the generator (eu2000) is off. Here's what I've chosen based on the recommendations of people here:

x2 Trojan T-105 golf cart batteries (6V wired in series for 12V @ 225 Ah)
Morningstar SureSine 300w Inverter
Iota 55A charger

Where I'm stumped is the wiring of this. The manual recommends fuses (3A AC and 100A DC). I would need jumper wires for the batteries, leads to the charger, and leads to the inverter.

Any recommendations on fuses? Amazon et al. seem to have some reasonably priced options (obviously appropriate sized fuses would be purchased for the holders):

http://www.amazon.com/dp/B0002KR88A/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2G720MI0W02ZF&coliid=I1KQAFE9OKQ04R
http://www.amazon.com/dp/B0002PUI82/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2G720MI0W02ZF&coliid=I2CA1SAGV0CQZU

How about wiring? What gauge wire, etc. I've got experience with AC wiring but not DC so this is a mystery.

I presume that the charger and the inverter should not be connected at the same time, correct? Is there a way to use a switch to select between the two so you don't have to physically move wires around?

Thanks.
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Comments

  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #2
    Re: Wiring up a Morningstar Suresine 300

    Welcome to the forum.
    I've been running 2 of those inverters for almost 6 years now. LOVE them!
    I know the book calls for 100 amp fuses on the input, and I now have 100 amp fuses on both of mine, but honestly, I ran them for years with 60 amp fuses and can't see any difference in normal day to day operation. Why did i change to 100 amp fuses? Because the book says so, and I assumed it must have something to do with allowing greater surge due to lower fuse resistance, before the inverter kicked out on surge overload. If it made a difference I couldn't detect it. BTW, neither one of them has ever blown a fuse. I use #4 wire for the short (4 foot) run to the inverters. You won't find any day to day difference between the AC and DC wiring, other than having to be very careful not to interchange the PLUS and MINUS. And of course voltage drop. A drop of 1.5 volts on a 115 volt circuit is only a bit over 1%, but when dealing with only 12 volts, that same voltage drop exceeds 10% loss.
    As to having the inverter and charger both connected to the batteries at the same time, this won't be a problem unless the charger shoves the battery voltage above 15.5, as that's the over-voltage shut down point of the inverter. it will restart however when the voltage drops back to 13.5 or so. This is it's normal operation. In normal solar system use, it's not uncommon in Winter when battery charge voltages need to be higher, to have inverters shut down on over-voltage, especially when doing an EQ charge.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #3
    Re: Wiring up a Morningstar Suresine 300
    Interlude wrote: »
    small battery backup system for power outages to run lights and whatnot when the generator (eu2000) is off. Here's what I've chosen based on the recommendations of people here:

    x2 Trojan T-105 golf cart batteries (6V wired in series for 12V @ 225 Ah)
    Morningstar SureSine 300w Inverter
    Iota 55A charger

    One more consideration: The Iota's are great chargers, but have low power factor. This means that your charger will take up most of the capacity of your generator. I don't know what your energy usage pattern will be, but you may find that your generator cannot charge the battery while running the household fridge, lights, etc.

    The Iota is a rugged and reasonably priced charger, especially if you are charging the battery from the grid.
    Interlude wrote: »
    I would need jumper wires for the batteries
    NO ! That is unsafe, unreliable, and may damage your equipment. Use permanent connections. If you need to frequently connect and disconnect the batteries, use Anderson connectors.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Interlude
    Interlude Registered Users Posts: 8 ✭
    #4
    Re: Wiring up a Morningstar Suresine 300

    Thanks to you both - should I use #4 wire for all the DC connections? What is a "permanent connection"? And are there chargers with a better power factor that aren't a fortune?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: Wiring up a Morningstar Suresine 300

    Wire size is dependent on two factors: the amount of current expected and the length of the wire run.

    4 AWG should be sufficient to handle the current of a 300 Watt, 12 Volt inverter: that is <30 Amps and that wire size is rate for >60. So long as the distance is less than 20 feet the Voltage drop should not be significant.

    A "permanent connection" is one that can not be disconnected without the use of tools. You definitely do not want to use the alligator clips of jumper cables; they have very small and uncertain contact area.

    Regrettably there are no stand-alone battery chargers that are truly suitable to RE applications (lack of programmable charge profile to meet the particular needs of the battery). The Iota line is about the best you can get, although there are some others which are similar. More or less, don't depend on it to do the same 'quality' of charging as the solar, especially not for full charge. They are fine to keep the SOC above the point where sulphation accelerates.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #6
    Re: Wiring up a Morningstar Suresine 300
    Cariboocoot wrote: »
    Regrettably there are no stand-alone battery chargers that are truly suitable to RE applications (lack of programmable charge profile to meet the particular needs of the battery).

    Xantrex has a new line of "TrueCharge2" battery chargers, which are PF corrected and have appropriate features for RE. I have not seen or used one, nor have I seen any reviews on this forum.

    I am interested in their 24 volt versions, but I would like to see some reviews.... If you buy one, be sure to let us know how it works for you.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #7
    Re: Wiring up a Morningstar Suresine 300
    Interlude wrote: »
    I would need jumper wires for the batteries.

    Until I read the posts from others, I didn't realize you were probably referring to automotive Jumper Cables. If this is true, I totally agree with statements that using these to connect your batteries to an inverter is a big no no. They don't make good, solid, low resistance connections. That's fine for starting a vehicle with a dead battery, but definitely not to power an inverter. There MUST be good, clean, solid and secure connections between the battery bank and the inverter, or the inverter will "think" the battery voltage is down, so will shut down with anything but the very lightest of loads.
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  • Interlude
    Interlude Registered Users Posts: 8 ✭
    #8
    Re: Wiring up a Morningstar Suresine 300
    waynefromnscanada wrote: »
    Until I read the posts from others, I didn't realize you were probably referring to automotive Jumper Cables. If this is true, I totally agree with statements that using these to connect your batteries to an inverter is a big no no. They don't make good, solid, low resistance connections. That's fine for starting a vehicle with a dead battery, but definitely not to power an inverter. There MUST be good, clean, solid and secure connections between the battery bank and the inverter, or the inverter will "think" the battery voltage is down, so will shut down with anything but the very lightest of loads.
    Yeah sorry about that, I didn't mean proper auto battery jumper cables, I meant cables from one battery to the next. I guess my question is, how do you attach the wires? I see #4 pre-built wires from NAWS with 3/8" lug connectors, how do those attach to the batteries? What else do I need to wire this?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Wiring up a Morningstar Suresine 300
    Interlude wrote: »
    Yeah sorry about that, I didn't mean proper auto battery jumper cables, I meant cables from one battery to the next. I guess my question is, how do you attach the wires? I see #4 pre-built wires from NAWS with 3/8" lug connectors, how do those attach to the batteries? What else do I need to wire this?

    Your T105's will have bolt terminals on them: http://www.solar-electric.com/trt16vo225ah1.html

    Those Blue Sea battery post terminal fuses will fit right on there, and the wire lugs will fit on the fuses. If you get a double fuse holder you have one fuse & post for the charge controller and one for the inverter right on the battery terminal. Very neat installation.
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  • Interlude
    Interlude Registered Users Posts: 8 ✭
    #10
    Re: Wiring up a Morningstar Suresine 300

    Thanks all, appreciate the hand-holding :)
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