Can I use my kill a watt ez as a battery monitor ?

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Thom
Thom Solar Expert Posts: 196 ✭✭✭
in Off Grid Solar & Battery Systems #1
If I did could I guess inverter losses ? Any tips to using it this's way ? After reading about it or 2 years I bought one . I can plug it into my inverter (750w harbor freight) .system listed below

Thanks Thom
Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added 2@ 100w panel with a midnight brat 
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #2
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    Re: Can I use my kill a watt ez as a battery monitor ?
    Thom wrote: »
    If I did could I guess inverter losses ? Any tips to using it this's way ? After reading about it or 2 years I bought one . I can plug it into my inverter (750w harbor freight) .system listed below

    No. A real battery monitor counts the amps going into and out of the battery. Your idea will only count what's going out of the battery. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Thom
    Thom Solar Expert Posts: 196 ✭✭✭
    #3
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    Re: Can I use my kill a watt ez as a battery monitor ?
    vtmaps wrote: »
    No. A real battery monitor counts the amps going into and out of the battery. Your idea will only count what's going out of the battery. --vtMaps

    How about the Rogue it has a display of watts in ? I don't yet understand I guess . One watt in the battery does not one out . Does a battery monitor reflect the loss ?

    Thom
    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added 2@ 100w panel with a midnight brat 
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,440 admin
    #4
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    Re: Can I use my kill a watt ez as a battery monitor ?

    A "true" battery monitor does keep track of the battery efficiency (as I understand). You can get Amp*Hour DC loggers, but they do not do that.

    Charge controllers can keep track of how much Amp*Hours (or Watt*Hours) they output, but they have no idea where that energy went (loads, battery, breaking water into oxygen+hydrogen, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
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    Re: Can I use my kill a watt ez as a battery monitor ?
    Thom wrote: »
    How about the Rogue it has a display of watts in ? I don't yet understand I guess . One watt in the battery does not one out . Does a battery monitor reflect the loss ?

    Thom

    Charge controller readouts will only show the power they put out, not the power taken from the battery.

    Your Kill-A-Watt will only show the power used by the AC loads, not the power going to the battery or the power used by the inverter.

    A battery monitor does just what the name implies: monitors the power going in to the battery (from all charge sources) and the power coming from the battery (including inverter consumption and the power lost in conversion to AC). It is really the only way to accurately measure power in and out, and it can be wrong if not programmed properly (correct capacity [which lessens over time] and efficiency, starting with a fully charged battery).
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #6
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    Re: Can I use my kill a watt ez as a battery monitor ?
    Cariboocoot wrote: »
    Charge controller readouts will only show the power they put out, not the power taken from the battery.

    Soon though Midnite will have a battery monitor module for their Classic which will measure amps across a shunt. I guess Apollo has a trimetric integrated into their charge controller, and I've heard one of the new systems from Outback or Xantrex has one built in.

    This is the threshold of a 'true' battery monitor, look at Trimetric if your looking for one...
    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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