Kill-O-Watt meter ?'s

shockman
shockman Solar Expert Posts: 113 ✭✭
I'm wondering if I was to plug meter straight into inverter and plug house into meter, which is how my system is set up, 3prong plug into side of inv. would this give me total consumption for a weekend?? and would it account for inverter draw?? or are those losses before getting to ac side?
4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Kill-O-Watt meter ?'s

    It will account for the whole house loads (excluding surge current starting fridge/etc.--Those amounts of kWH are usually very small over all and can be ignored). The inverter efficiency (loses) could be estimated at ~0.85 (or if you have an efficiency curve for your inverter--use those numbers for the average draw). Of course, the typical kWH meter is good for a maximum of ~1,800 watts/15 amps maximum.

    There are different models of Kill-a-Watt meters. At least one has a battery and can "remember" readings if the AC power is turned off... The ones without backup batteries will reset to zero. So--if you cycle the AC Inverter during the weekend, you may need to take the kWH readings before shutting down the inverter during non-use.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Kill-O-Watt meter ?'s

    It would show how much power is being used in AC terms, but it will not show the consumption of the inverter or any losses between the batteries and AC output.

    The only way to measure all the power going out is with a meter on the DC side. A battery monitor can be used for this (by leaving out the input from the charge controller it will measure only the outgoing current).

    On the whole, unless there are significant DC only loads the Kill-A-Watt measurement will be accurate enough providing you add in the consumption figure for the inverter (it should be in the manual). Wiring losses should be minimal and thus within the margin for error.

    People who obsess over every hundredth of a Watt/Volt/Amp tend to have dysfunctional systems because they try to run without big margins for error. That's like expecting the weather to be exactly the same every day. It never is. :roll:
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Kill-O-Watt meter ?'s
    It would show how much power is being used in AC terms, but it will not show the consumption of the inverter or any losses between the batteries and AC output.
    There are good indications from users that the Kill-a-Watt gives an accurate indication of both power (watts) consumed by either a resistive load or a linear inductive load like a motor and of the VA consumed by a linear reactive load. But they have shown some pretty wild readings for both watts and VA when the biggest part of the load is non-linear with a low distortion power factor (for example CFLs, computer power supplies and battery chargers.)

    Just keep that in mind when interpreting the results you get.
    SMA SB 3000, old BP panels.
  • Skippy
    Skippy Solar Expert Posts: 310 ✭✭
    Re: Kill-O-Watt meter ?'s
    BB. wrote: »
    Of course, the typical kWH meter is good for a maximum of ~1,800 watts/15 amps maximum.

    There are different models of Kill-a-Watt meters.

    -Bill

    I agree with bill, I have a k.o.w meter, and can test ALMOST everything that plugs into 120 V . . . EXCEPT my washing machine. . as soon as it trys to draw the start up surge, it beeeeeps. . . and dies, then I have to pull the plug and reset. . .

    Sounds like your idea would work, but for testing "whole house" . . you can overload the k.o.w meter. :D
    2 - 255W + 4 - 285W PV - Tristar 60 amp MPPT CC / 3 - 110W PV -wired for 36V- 24V Sunsaver MPPT CC / midnite bat. monitor.
    1 KW PSW inverter 24V / 2.5 KW MSW inverter-24V ~ 105 AHR battery.
    3 ton GSHP.- 100 gallon warm water storage / house heat - radiant floor / rad
    9 -220W PV - net meter - Enphase inverters and internet reporting system.
    420 Gallon rain water system for laundry.***  6" Rocket Mass Heater with 10' bed for workshop heat.
    Current project is drawing up plans for a below grade Hobbit / underground home.
    Google "undergroundandlovinit" no spaces.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Kill-O-Watt meter ?'s

    Do you have a link to the brand/make/model/type of "k.o.w." meter you have?
  • shockman
    shockman Solar Expert Posts: 113 ✭✭
    Re: Kill-O-Watt meter ?'s

    meter is model P4460, front has P3 on it, says max current 15A, max power 1875VA. What i would be running at this time of year would be a couple of CFL's, T.V and sat. box. Kitchen and Dining room have florescent fixture's. I might also set electric coffee pot to make my morning coffee just for a yuk. Oh and probably have laptop plugged in for a few hours
    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Kill-O-Watt meter ?'s

    OK, found a link to your Kill A Watt: http://www.p3international.com/products/p4460.html
    It looks somewhat similar to the one I have, but is different. One thing we don't know, is if you intend to use a pure sine inverter, or a cheaper MSW inverter. My concern is that some of the Kill-A-Watt devices have an internal power supply that overheats and may burn out if used on other than pure sine wave electricity. Some will work OK, others not so. I didn't see any mention of MSW in the specs, so take that into consideration. The CFLs will work ok on MSW, but the TV and sat receiver may or may not experience a short life on MSW. It's a trial and error thing and depends on how the power supply in each device is designed.
    All your loads are small - - except for the proposed coffee maker. That thing will suck back the power and will require a large inverter and a battery pack heavy enough to supply what big demand. The bigger the inverter, generally, the greater the power consumption will be from your batteries just to keep the inverter running. It might be something to consider and perhaps look at a non-electric way of making coffee.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Kill-O-Watt meter ?'s

    I think if the K-a-W meter is over (at least) 4-5 years old, I believe they will work fine on MSW inverters (at least they will not fail).

    Somebody here contacted the factory once and found that some revision "X" or later was fine with MSW (I could not find the post here--may have been lost in a VB upgrade years ago).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • shockman
    shockman Solar Expert Posts: 113 ✭✭
    Re: Kill-O-Watt meter ?'s

    Inverter is an old Trace 2012, supposedly 2000w but I'm sure I read 1500w continuous, manual is at the cabin. It is MSW. I do have propane stove for coffee and generally perc it but I'm trying to get system big enough to use the programable pot :>) I am presently useing 450A/H of battery and getting about 36A of chargeing
    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Kill-O-Watt meter ?'s
    shockman wrote: »
    Inverter is an old Trace 2012, supposedly 2000w but I'm sure I read 1500w continuous, manual is at the cabin. It is MSW. I do have propane stove for coffee and generally perc it but I'm trying to get system big enough to use the programable pot :>) I am presently useing 450A/H of battery and getting about 36A of chargeing
    That inverter would have no problem with the coffee pot and you have plenty of Battery. The problem is that the Pot Timer MAY have a issue with MSW. You'll have to test it and see. If it runs fast or slow over 24 hours you may have to put a off set in the start time to compensate for it.

    Back in the day ( before TSW ) I'v had clocks that would gain as much as 4 hrs in 24 hours and some that would run as much slow, some just a few minutes a day. Even with TWS, they can get off some.

    You do realize that the pot will pull 100 + amps DC when it's making coffee. I hope you have big cabling.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭
    Re: Kill-O-Watt meter ?'s
    That inverter would have no problem with the coffee pot and you have plenty of Battery. The problem is that the Pot Timer MAY have a issue with MSW. You'll have to test it and see. If it runs fast or slow over 24 hours you may have to put a off set in the start time to compensate for it.

    Back in the day ( before TSW ) I'v had clocks that would gain as much as 4 hrs in 24 hours and some that would run as much slow, some just a few minutes a day. Even with TWS, they can get off some.
    You do realize that the pot will pull 100 + amps DC when it's making coffee. I hope you have big cabling.

    Yes I've noticed that a clock radio I had in bedroom would go out of time within a few days, but have not noticed the coffee pot going out enough to notice to be a problem but it is usually only on for overnight as in winter I shut it off as soon as I get up and put pot on wood stove to keep warm, learn't that the hard way, heating element sucks a lot of juice :>)
    About the cabling I'm assuming that we are talking between batts and inverter?? they are about 5-6ft long 0 guage ???? I do not have any fuse or breaker in line, is that a problem????
    Marc
    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Kill-O-Watt meter ?'s
    shockman wrote: »
    I do not have any fuse or breaker in line, is that a problem????
    Marc

    Only if something goes wrong.
    1500 Watts on 12 Volts = 125 Amps. Anything shorts out in the inverter ... the wire goes up in flames.
    0 AWG is technically enough for this load & Voltage, but even at 6' length you may experience noticeable Voltage drop at the inverter the closer you get to full power (like running that coffee pot). The lower the battery Voltage, the greater the current, the more the heating of the wire.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭
    Re: Kill-O-Watt meter ?'s
    Only if something goes wrong.
    1500 Watts on 12 Volts = 125 Amps. Anything shorts out in the inverter ... the wire goes up in flames.
    0 AWG is technically enough for this load & Voltage, but even at 6' length you may experience noticeable Voltage drop at the inverter the closer you get to full power (like running that coffee pot). The lower the battery Voltage, the greater the current, the more the heating of the wire.

    Okay so tell me the "easy" proper way to fuse that line? positive cable only I'm assuming
    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Kill-O-Watt meter ?'s
    shockman wrote: »
    Okay so tell me the "easy" proper way to fuse that line? positive cable only I'm assuming

    Yes. Simplest thing is to read the manufacturer's recommended fuse size in the manual.
    Otherwise you do the maximum power / minimum operating Voltage equation to come up with the peak current, then do the NEC over sizing (* 1.25 * 1.25, round up) which gives the fuse size and size the wire to handle more than that.

    So 1500 Watts with a 12 Volt cut-out is the 125 Amps mentioned, and the fuse size ends up being 200 Amp and the wire size goes to 3/0. You can undersize this providing the ratios are right. For instance your 0 gauge is rated for 150 Amps, so it needs to be protected by a smaller fuse than that. Like 100 Amps. Keep in mind that will limit your maximum power to about 1200 Watts; draw more and the fuse will blow.
  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: Kill-O-Watt meter ?'s

    I'm thinking one of these https://bluesea.com/category/3/10/productline/overview/378 with the appropriate fuse. At least, that's what I've been planning on.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭
    Re: Kill-O-Watt meter ?'s

    I also have a few ?'s about all the wireing at batts. I am assuming I will need bus bars?? but I have several wires +&- on bats, I have lines for charge contoller, wind mill, inverter, array mover thingy, and straight 12V supply to several 12V plugs and access.
    At this time I have supply lines from array and WM coming into a metal box { #4awg} they are slit bolted to #6awg and out of box, the two supply lines have breakers on them from there to CC and batts for WM.
    I am now working with GC batts that have been abused through the learning process, I am useing 4 but have 4 more that came out of bank recently. I would like to have some easy way of switching from one set of 4 to another be it for chargeing or drawing???? I'm sure I could milk another few years out of them.
    Any direction on all this wireing would be appreciated! Keep in mind that when I asked Westburne Electric a wholesaler that we deal with for other stuff about busbars I got a funny look, like what you talking about boy?? So according to my 18yr old son I should call them something else, forget what he called them? diversion bar or something like that?? I see on line these nice E-Panels that seem to accomadate a lot of this wireing but they are also $600 and up. Surely there are cheaper ways of doing this and being safe???????
    Marc
    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Kill-O-Watt meter ?'s

    One thing not mentioned re the programmable coffee maker being used on MSW inverter, is the real possibility of the electronics in the programmable coffee maker not surviving on MSW. It MAY live just fine with MSW, but it may also just as easily pack it in and give up the ghost, or "magic smoke" after a very few minutes. It's trial and error, hit or miss. No way to predict.
    Just something to keep in mind, a heads up on what could happen.
  • Skippy
    Skippy Solar Expert Posts: 310 ✭✭
    Re: Kill-O-Watt meter ?'s
    BB. wrote: »
    I think if the K-a-W meter is over (at least) 4-5 years old, I believe they will work fine on MSW inverters (at least they will not fail).

    -Bill

    The K.A.W meter I have here is a P4400 with the same specs as yours. . . last night, I plugged into a/c power, and hooked up 2 - 100 watt light bulbs, and then turned on an 1800 watt space heater. . . at start up, the display flashed a few times, and it beeped 3 times (1945 watts) . . . after the start up surge, it displayed the power usage just fine . . just under 1800 watts - guess the heater is not pulling full power or drops off a bit after start up . .. :p My washing machine must pull alot more than that to completely turn it off

    I find that when I plug in the meter onto my msw inverter, turn on a 11 watt cfl, then push the "hz" button on the meter . . it will read DC voltage. . . but if you are pushing 500 watts thru the meter/inverter, then you get 59.8 "hz" . .

    It would be interesting to see what results you get with your set up. . . especially at lower power levels. .
    2 - 255W + 4 - 285W PV - Tristar 60 amp MPPT CC / 3 - 110W PV -wired for 36V- 24V Sunsaver MPPT CC / midnite bat. monitor.
    1 KW PSW inverter 24V / 2.5 KW MSW inverter-24V ~ 105 AHR battery.
    3 ton GSHP.- 100 gallon warm water storage / house heat - radiant floor / rad
    9 -220W PV - net meter - Enphase inverters and internet reporting system.
    420 Gallon rain water system for laundry.***  6" Rocket Mass Heater with 10' bed for workshop heat.
    Current project is drawing up plans for a below grade Hobbit / underground home.
    Google "undergroundandlovinit" no spaces.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Kill-O-Watt meter ?'s
    Rybren wrote: »
    I'm thinking one of these https://bluesea.com/category/3/10/productline/overview/378 with the appropriate fuse. At least, that's what I've been planning on.
    Those will work great, but with one caveat, they have a 3/8's inch hole in the base that attaches to the battery post, most battery posts these days have a 5/16 inch bolt. If you do not put a washer of the appropriate size on the battery post before the fuse holder base the lead will pull up into the hole and pull the bolt almost out of the post. It's kind of silly because they have a 5/16" on the fuse / lug bolt.
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Kill-O-Watt meter ?'s
    Rybren wrote: »
    I'm thinking one of these https://bluesea.com/category/3/10/productline/overview/378 with the appropriate fuse. At least, that's what I've been planning on.


    I use one of these on the positive battery bank terminal.

    FWIW - the cheapest place of I've seen the fuses is at Waytek. Link HERE.

    For some reason Waytek sells the double fuse holders for these but not the single ones. I got my fuse holder from Hodges Marine - best price I could find at the time.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Kill-O-Watt meter ?'s

    If you have several DC connections to make using bus bars is a better way that trying to pile all of them up on one bolt. Your supply store probably doesn't deal with DC stuff and so is unfamiliar with the term.

    Some are easy to get: http://www.solar-electric.com/tbb.html
    Others a tad more exotic: http://www.solar-electric.com/podibl.html
    Some people make their own.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭
    Re: Kill-O-Watt meter ?'s
    If you have several DC connections to make using bus bars is a better way that trying to pile all of them up on one bolt. Your supply store probably doesn't deal with DC stuff and so is unfamiliar with the term.

    Some are easy to get: http://www.solar-electric.com/tbb.html
    Others a tad more exotic: http://www.solar-electric.com/podibl.html
    Some people make their own.

    Okay some dumb ???'s about distribution blocks, so they are not AC or DC just a conductive piece of metal right? so if I come off the batts with 0awg to the block, then attatch all smaller lines to block whether they are supply or load??? and do I still use seperate 0awg to inverter?? or is the block that has 2 large inputs going to pass inline power??
    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Kill-O-Watt meter ?'s

    Distribution blocks are just conductors. They don't care about AC or DC or which way the power goes. Only keep it under the rated current.

    The usual application is to connect the big wire from the battery to the big connector, then pull off the smaller connectors for whatever is needed. The smaller ones will be handling less current, but the big one will be handling the combined current of all the others as a net current in or out of the battery.

    If anything requires a lead larger than will fit in the connector, wire it separately. As you suspect the Inverter will have its own wires & fuse/breaker to the battery (which may also have a fuse right at the terminal - there's lots of discussion about making wiring safe along these lines) and the distribution block would got to the charge controller (usually no larger than 6 AWG) and DC loads as applicable.

    Keep in mind that if you wire in a shunt for a battery monitor is still has to go between the battery negative and ALL other (-) connections. Otherwise it would miss some of the current flow and not be accurate.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Kill-O-Watt meter ?'s

    The other thing to keep in mind is that the battery bus common point has very high current available (hundreds to thousands of amps)--And any wire/cable leaving the bus should be protected against short circuits with an appropriately rated fuse/breaker (typically in the positive lead).

    While you can run a heavy wire from the battery bank to the inverter then to the solar charge controller--We try to disswade people from doing that. It brings a 200 amp+ capable circuit (for the AC inverter) to a 30-90 amp charge controller unless additional fusing/breakers are added.

    And, AC inverters (and many other loads) are electrically "noisy". A noisy inverter can confuse a daisy changed charge controller.

    "Star" or home run cables back to the battery bank tend to have less "crosstalk" between devices because the battery bank filters out some/much of the electrical noise.

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