Measuring KWH on major appliances.

mryimmersmryimmers Posts: 111Solar Expert ✭✭✭
Hi all,
I am planning to build a new house in the not too distant future and am considering the possibility of keeping it off grid.
We are currently "on grid" and all of our major appliances are electric. This includes clothes dryer, hot water heater, cook top and oven. We have a pretty good handle on our usage, and I would like to use our history to help in planning an off grid system.
My question is how do I measure the KWH used by the above mentioned appliances so that I can remove that amount from my daily required KWH? All those appliances would be propane fired in the off-grid build. Home heating is wood, with propane back-up. 
Is there a clamp-on amp-meter that can measure KWH over time? Then I could just put it on any of those appliances for a 1 or 2 months at a time and get a pretty accurate idea of how many KWH each one uses, and take that amount off of our current usage, which is in the 24-30 KWH per day range, then I would be left with a number that should be pretty close to what would be required for a system.   thanks hh
510 watt pv, TS-MPPT 60, Exeltech XP1100, XP600 & XP250 @ 24V, 4x Trojan 105RE, Trimetric 2030, Yamaha EF2400i gen.

Comments

  • Wheelman55Wheelman55 Posts: 47Registered Users ✭✭
    edited July 2016 #2
    For $30 you can get a P3 Kill-a-Watt meter. 

    http://www.p3international.com/products/p4400.html 

    Be aware that it will only measure 120v and a max of 15 amps. 

    You will also need to know the surge amps on each appliance in order to calculate true needs for solar. Enjoy the journey. 
    Building Off-Grid in Terlingua, TX
  • jonrjonr Posts: 1,070Solar Expert ✭✭✭✭
    For 240V and more amps, search ebay for "100A AC digital KWh watt meter".   Could be installed at your panel.
  • BB.BB. Posts: 27,789Super Moderators admin
    I don't remember where you are located... But, if you are around Lake Superior, what are you going to do in winter when you have something like 2-3 hours of sun per day in the winter. Going to go with genset/wind turbines?
    • 30,000 WH per day * 1/0.52 typical off system eff * 1/2.5 hours of sun (winter) = 23,077 Watt array nominal
    • 30,000 WH per day * 1/0.85 inverter eff * 2 days of storage * 1/0.50 max discharge * 1/48 volt battery = 2,941 AH @ 48 volt battery bank
    • 2,941 AH * 59 volts charging * 1/0.80 charger eff * 1/0.80 genset derating * 0.10 rate of charge = 27,112 VA rated genset minimum
    That is a quick estimate of what you would be looking at if you want to continue to use 30 kWH per day in winter.

    For measuring larger electric appliance usage--You can get whole house monitoring systems like this (some models can measure several specific circuit energy consumption at the same time).

    http://theenergydetective.com/

    -Bill


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mryimmersmryimmers Posts: 111Solar Expert ✭✭✭
    I have a kill-a -watt meter, very handy tool!! But I want to determine what my major appliances are using and be able to subtract that off of the 24-30 KWH that I use now, but being that they are all hard-wired in it isn't so simple as plugging in the kill-a-watt.
    I don't intend to need anywhere near 30 KWH per day if off grid. I was guessing more like 5ish, but I don't want to guess. I'll check those suggestions, I suppose it will require wiring something into the circuits I wish to check. I am in Thunder Bay Ontario.   Thanks guys!!  
    510 watt pv, TS-MPPT 60, Exeltech XP1100, XP600 & XP250 @ 24V, 4x Trojan 105RE, Trimetric 2030, Yamaha EF2400i gen.
  • BB.BB. Posts: 27,789Super Moderators admin
    The Energy Detective--Uses a CT (current transformer). You open your main breaker panel and clip a CT on the lead you want to measure power on. Can do the mains, and/or branch circuits.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mryimmersmryimmers Posts: 111Solar Expert ✭✭✭
    Checking that out, thanks Bill!!

    510 watt pv, TS-MPPT 60, Exeltech XP1100, XP600 & XP250 @ 24V, 4x Trojan 105RE, Trimetric 2030, Yamaha EF2400i gen.
  • mike95490mike95490 Posts: 7,874Solar Expert ✭✭✭✭
    edited July 2016 #8
    24-30KWh daily is going to require a large system.  2 people, 3 fridges and 3 hours of water pumping and I do 12KWh a day in the summer, and just 7 in the winter.   wood and propane heat, propane dryer, front load washer, Bosch dishwasher and B&D electric toaster.

    BEWARE the gas heating appliances, often the oven and clothes drier have a "glow coil" ignition system that uses 400W to ignite and 200w to monitor the presence of the flame
    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
    gen: http://tinyurl.com/LMR-Lister ,

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