Grid Tie cooling fan

ThomasThomas Solar Expert Posts: 291 ✭
in Advanced Solar Electric Technical Forum #1
I have a 1200 watt grid tie inverter and 1030 Watts of power this Dec.:p
I have had a 1000 watt inverter that sorta quit a few summers ago[ due to heat/insolation factor..?]
I have a diode hooked up after the array input and before charger , batteries and inverter.
I have a 7" reversible cooling fan hooked up to the inverter, it is 80 watts/ 7A.:cry:
I have had no luck trying to regulate the speed of this fan as connected to the array for daylight operation.
Can anyone recommend a resistance plan to get a maximum of 2A to the fan at full panels output? -and 0% at 0%.
Thanks, or I am going to have to try more potentiometer/ rheostats...:grr:confused:
_
Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: Grid Tie cooling fan

    I just aimed a $5 desktop oscillatingAttachment not found. fan at my inverter, and plugged it into a timer.
    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 ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
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  • ThomasThomas Solar Expert Posts: 291 ✭
    #3
    Re: Grid Tie cooling fan

    Oh yeah, I did that at the end of the hot season here, I guess I could do that again, I was looking for a more mindless integrated solution for big brother, I guess just opening the cabinet door its in and putting a fan to it would work.

    Whats up with Pulse Width Modulating everything?[anyway?]

    and why cant I find a rheostat for 5 bucks? All I can find is 20 dollar potentiometers.
    What about a ceramic resistor? the dump load type? to vary proportionately to PV output up to a max of 2A?
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • BB.BB. Super Moderators, Administrators Posts: 32,656 admin
    #4
    Re: Grid Tie cooling fan
    Thomas wrote: »
    Whats up with Pulse Width Modulating everything?[anyway?]

    Because it uses/wastes less power... A resistor will have P=V2/R=I2/R heating losses.

    A "transistor" turning on and off will have very little self heating losses (a few percentage points at full power).

    So, it is not only the cost of the "waste heat", it is that the waste heat needs to be "gotten rid of". Meaning that you need a larger device+heat sink+cooling air flow. A 300 Watt AC dimmer for lighting will fit into a standard wall box. A 100 watt+ resistor--Would catch the wall on fire.

    Of course there are issues--PWM makes a lot of electrical noise and can even make for a 120 Hz hum/buzz in light fixtures/CFLs/etc.

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