question about a watt meter

Leehamrick
Leehamrick Registered Users Posts: 17 ✭
in Solar Beginners Corner #1
Hi I have a question about this watt meter does it go between the panels and the control box
or between batteries and control box? or what?
thanks

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: question about a watt meter

    I presume "control box" is charge controller and you have one that does not have a meter on it?
    As such a Watt meter would go on the circuit you want to measure the Watts on. Now that sounds ridiculously simple, but a complex controller will be able to see Volts, Amps, and Watts both going in to it and out of it.
    In my opinion the one that's of the most value is the power going out of the controller. Be sure the wiring is adequate to take the maximum current (of the panel & controller output) and that there's an appropriate fuse/breaker as well.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: question about a watt meter

    a better question might be, what did you do with the instruction manual?:confused:
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #4
    Re: question about a watt meter

    It is hard to judge by the picture, but it looks like this meter is too small to handle 100A through.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
    Re: question about a watt meter
    NorthGuy wrote: »
    It is hard to judge by the picture, but it looks like this meter is too small to handle 100A.

    You mean it's sort of like a Toyota Corolla with a speedometer that pegs at 200 MPH? :D
    But seriously, the wire size relative to the apparent size of the meter would suggest 10 to 20 amps max without serious overheating problems.
    100 amps would surely yield smoke.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #6
    Re: question about a watt meter

    I bought one of these ($25 ), never hooked it up yet, it's rated at 250 amps. I saw it on a wind site. There is something weird about the Voltage readout, it measures 12 V and you have to multiply it for 24 V or 48 V. Whats nice, it'll take up to 2/0 cable.

    Attachment not found.


    http://www.sonicelectronix.com/item_38978_Xscorpion-DAV02P.html

    http://www.mwands.com/index.php?main_page=product_info&cPath=41&products_id=490 ( Instructions )

    http://www.sonicelectronix.com/cat_i702_voltage-monitoring-systems.html ( Voltmeters )
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,023 ✭✭✭✭
    #7
    Re: question about a watt meter

    That watt meter the op has looks like it's for radio control purposes. Little LiPo batteries, speed controllers and electric motors.

    raalph
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #8
    Re: question about a watt meter
    Ralph Day wrote: »
    That watt meter the op has looks like it's for radio control purposes. Little LiPo batteries, speed controllers and electric motors.

    It looks a lot like the Doc Watson meter. Perhaps the older style.
    Leehamrick wrote:
    does it go between the panels and the control box or between batteries and control box? or what?
    Check out the online instructions and wiring diagrams for the Doc Watson meter.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #9
    Re: question about a watt meter

    Here is a (the?) website with Doc Wattson FAQs and wiring instructions.

    http://www.rc-electronics-usa.com/electrical-test-equipment.html

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #10
    Re: question about a watt meter
    BB. wrote: »
    Here is a (the?) website with Doc Wattson FAQs and wiring instructions.

    http://www.rc-electronics-usa.com/electrical-test-equipment.html

    -Bill

    That shows that the 100A measurement is "peak". Since the wires are only 14g gauge, but with high temp insulation, I would expect that steady state current would be limited to 25A, or somewhat more if the meter leads are kept short and are connected to much heavier gauge wires that can conduct the heat away.
    14 gage, stranded, high flex, high temperature silicone rubber insulated wires. Supplied without connectors

    If connected using the three terminal method, only the black wires will have to carry much current.
    SMA SB 3000, old BP panels.
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  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    #11
    Re: question about a watt meter
    inetdog wrote: »
    That shows that the 100A measurement is "peak". Since the wires are only 14g gauge, but with high temp insulation, I would expect that steady state current would be limited to 25A, or somewhat more if the meter leads are kept short and are connected to much heavier gauge wires that can conduct the heat away.



    If connected using the three terminal method, only the black wires will have to carry much current.

    FWIW I have one of those Doc Wattson meters that I use on my eBike. It's wired with the 3 wire method using 10AWG (via Anderson connectors) and it handles sustained 35 amps (at 48V nominal) with ease.

    I also own one of THESE chinese clones which is nice because it has a backlight. I have only played around with it but many in the eBike world use them with good success.

    So yes 100A is likely only a peak current capability but I can say from personal experience that sustained current to 35 A is ok.

    The meter in the OP looks like another Doc Wattson clone to me.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #12
    Re: question about a watt meter
    mtdoc wrote: »
    I also own one of THESE chinese clones which is nice because it has a backlight. I have only played around with it but many in the eBike world use them with good success.

    I looked at the link for the 'Turnigy' chinese clone. There is no mention of AC or DC capabilities in the specs. I presume it is DC like the Doc Watson? --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    #13
    Re: question about a watt meter
    vtmaps wrote: »
    I looked at the link for the 'Turnigy' chinese clone. There is no mention of AC or DC capabilities in the specs. I presume it is DC like the Doc Watson? --vtMaps


    Yep. DC it is....
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