Inverter fans not coming on

Fabian
Fabian Registered Users Posts: 134 ✭✭
in Advanced Solar Electric Technical Forum #1
I have a Reliable brand 24v 3000watt 120vac pure sinewave inverter and I realize that the fans are not coming on.
It comes with (2) 24v fans and I test them recently and they are working perfectly but the inverter circuit somehow is not triggering them when it gets hot or reach a certain temperature. I have seen the inverter gets so hot that it automatically cuts off the output to prevent damage from occurring. I read on the net that the inverter fans comes in at 45 degree celcius but I passed that rating lots of time and yet no fan comes on.

In the meantime I have connect the fans straight so that when the inverter turns on they come on same time but they are so loud and I don't wish to have this as a permanent setup. I am hoping someone can tell me what I can do to repair the issue so that the circuit will trigger the fans at the appropriate temperature range or is there some other alternative means of getting the fans to come on at a certain temp range using the internal/default heat sensing ntc resistor? or even a different ntc resistor?


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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    The "ntc" resistor is not wired to the fans, it's wired to control circuits in the inverter.

    A "thermal snap disc" thermostat switch would be wired in series with the fans, but that's so old school and trouble free.   

    I say bug mr Reliable till they make you happy.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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    solar: http://tinyurl.com/LMR-Solar
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  • Fabian
    Fabian Registered Users Posts: 134 ✭✭
    #3
    How exactly should I wire the thermal snap disc?
    Please explain in full details.
    Also what's the best specifications to get for the thermal snap disc?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,626 admin
    #4
    This is an example (mounting flange options, perhaps a bit higher temperature or fans may be on too much of the time):


    Fan power to the switch. Then to the Fan. Then to fan power return.

    But--I highly recommend that you do not play around inside your inverter. The chances that you may break something is pretty high (or you short high current low voltage DC bus, or short the high voltage output, etc.).

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    edited June 2018 #5
    I actually like Bills idea, was about to suggest it myself. If you are confident enough to hard wire them, this should be an easy solution.

    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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  • Fabian
    Fabian Registered Users Posts: 134 ✭✭
    #6
    Here is a nice digital one that I found. The only issue is that the range starts from 50 degree Celsius and cannot start below that.

    https://m.ebay.com/itm/12V-24V-220V-Digital-LED-Temperature-Controller-Thermostat-Control-Switch-Probe/232605014144?hash=item362856d880:m:mhpeM-VQRT2Ty6YNyvzEn5g


    Would a starting point at 50 degree celsius be ok and not cause a thermal meltdown of the fets or the other parts inside of the inverter?
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #7
    Fabian said:
    Would a starting point at 50 degree celsius be ok and not cause a thermal meltdown of the fets or the other parts inside of the inverter?
    Bill linked to one that works at 120 degrees Fahrenheit, about the same 48 degrees C , I would rather have a simple sensor than a display... 

    I would think this simple 40 degree c, bimetal switch would work;

    https://www.amazon.com/uxcell-Bimetal-Temperature-Thermostat-Celsius/
    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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,626 admin
    #8
    Remember that these snap disk switches are still only "accurate" to ~+/- 5C (9F)... I am not recommending this as a fix. Just trying to answer some questions.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Fabian
    Fabian Registered Users Posts: 134 ✭✭
    #9
    Thanks guys for your solutions. I am going to try the bi-metal switch as the price is so cheap on ebay and it is quite simple?

    Would it be best to use a thermal paste to stick it to the heatsink?
    Also would it be best to stick it beside where the existing ntc resistor is placed on the board as I am guessing that spot would be the hottest point on the heatsink when you are pulling lot of wattage?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,626 admin
    #10
    Probably will not matter too much. Just get well mounted so that the switch does not fall off the heatsink and short the electronics.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Fabian
    Fabian Registered Users Posts: 134 ✭✭
    #11
    When buying the bimetal temp switch it would be best to buy it as N.O(normally open)?
    For eg. If it states 45degree celsius N.O does that means that whenever the temp reaches 45 degree the circuit would be then change from N.O to N.C. thereby sending current to the fan and when the temp drop to about 30 it would change back to N.O which would break the connection to the fan?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,626 admin
    #12
    That is correct.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Fabian
    Fabian Registered Users Posts: 134 ✭✭
    #13
    Thanks for the info. I greatly appreciate the support.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,626 admin
    #14
    You are very welcome Fabian.

    Good luck!
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #15
    Let us know how it turns out!
    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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  • Fabian
    Fabian Registered Users Posts: 134 ✭✭
    #16
    ok. i buy the bimetal temp switch so just waiting on it to come now so i can install it and let u guys know if it works ok.
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