Forum Discussion

1995brave's avatar
Aug 11, 2017

AC panel Meter with 100 amp current transformer

Link: http://www.mpja.com/08-10-17100 amp.asp?r=179748&s=3

Great for 30 amp RV's See your AC voltage and how much current you are drawing on one panel meter.
  • I like mine so much
    I plan on getting another meter and mounting it the generator
  • I did similar on our 30 amp TT using a Datel LED ammeter which has an integral C/T and a Datel LED voltmeter. Made in the US and high quality but cost a fair bit more. Both fit into a 1-gang outlet box. With 2 meters, I get real-time readout with no automatic or manual scrolling involved.

    We also have a PI EMS but found the continual scrolling annoying so the display got mounted inside a cabinet so that error codes can be read if needed.

  • @ Matt

    two meters, two coils
    one on each leg

    just add them together for the total

    works for both 30 and 50 amp power

    power will never be exactly the same on each leg
    and you measure the power thru each hot leg
    neutral NOT in the calculations
    neutral only carries the 'difference' between the two hots when on 50a service
    you have too measure both legs to get the amount of power used

    on 30a neutral and hot are the same, but the load will be split between the two legs in the rv

    i built a portable one with a 100a meter and 30a plugs
    so i can monitor the generator with A/C loads
    or 30amp shore
    great for testing loads and measuring PF watts and voltage, have to calculate the VA using the other numbers, even counts KW hours


    no this is NOT a K-A-W
    this is a home built good for 100 amps and uses 30amp RV plugs
    Designed to be plugged into shore power or generator
    one could be built for 50amp, but i built this one for 30amp
    mainly for generator use/monitor

    PICTURES NOT TAKEN TODAY
    they are from an earlier post about the meter build


    Click For Full-Size Image.


    Click For Full-Size Image.


    Click For Full-Size Image

    YEAH i should have turn the meter 90 deggrees
    maybe on the next one ?
  • I just installed my EMS-HW30C and it's been awesome. I love how I can see all the parameters on the remote display.
  • Matt_Colie wrote:
    What I am still working on is how to get a current transformer to read right for both 30 and 50 amp shore power. The coach is wired for 50 but we frequently have to settle for 30.

    No fancy switching is allowed and it has to be internal to the coach.

    Matt


    I'm thinking you could calculate it by using a coil on one leg and another on the neutral. For 50 amp service, the second leg would be the difference between the neutral and one sensed leg. For 30 amp, the readings off both coils would be the same. Or you could just use 3 coils, the neutral for 30 amp service.

    An arduino or Raspberry pi could do this automagically pretty easily.
  • Matt_Colie wrote:
    What I am still working on is how to get a current transformer to read right for both 30 and 50 amp shore power. The coach is wired for 50 but we frequently have to settle for 30.

    No fancy switching is allowed and it has to be internal to the coach.

    Matt


    Gave up trying to do this too.
    I bought a Progressive Industries EMS system and it displays totals regardless of 30/50 connection.
    Just one more reason to have one! :)
  • Matt_Colie wrote:
    What I am still working on is how to get a current transformer to read right for both 30 and 50 amp shore power. The coach is wired for 50 but we frequently have to settle for 30.

    No fancy switching is allowed and it has to be internal to the coach.

    Matt


    Get another pickup coil and use a double post, double throw toggle switch. Read one leg of 50 then flip the switch to the other.

    Or to be really cool, install another meter on the second 50 amp leg
  • What I am still working on is how to get a current transformer to read right for both 30 and 50 amp shore power. The coach is wired for 50 but we frequently have to settle for 30.

    No fancy switching is allowed and it has to be internal to the coach.

    Matt
  • Link doesn't work ... preview before you post and you can avoid errors like this. ;) No matter, my Progressive EMS, a device every RV owner would benefit from having, tells me everything I want to know about incoming source power. :B