Help on DC amp clamp meters

DJuan222DJuan222 Posts: 22Registered Users ✭✭

Comments

  • jonrjonr Posts: 949Solar Expert ✭✭✭✭
    I think it does what the description says - both AC and DC.
  • littleharbor2littleharbor2 Posts: 877Solar Expert ✭✭✭✭

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • DJuan222DJuan222 Posts: 22Registered Users ✭✭
    OK now that I got the meter I feel dumb...well kinda

    Cant figure out why I can get the clamp to work and the lines from the panels + and the + from MPPT to batteries ( accurate to what the mppt reads )  but I cant get it to work on the 12 v 300amp line from the batteries.  its like 0 ga unshielded cant get any V or A even on the end where connected to inverter. Yes its set to DC, the system works been the a year. get 0 reading on car battery also

    what am i doing wrong on the 12v stuff ??
  • BB.BB. Posts: 27,351Super Moderators admin
    When measuring volts--You are using the +/- leads from the meter? (some meters have an AC non-contact voltage sensor--But that will read zero volts if trying to non-contact sense DC voltage).

    If you are using the leads, put one lead on a battery - terminal and keep it there. Use the other + lead to probe each connection point in your system around the battery bank. See if everything "makes sense" or not.

    If you have a 12 volt system... Get a (cheap) 12 volt Test Light from the auto parts store (looks like a clear screwdriver with a sharp point and a clip lead out the back).

    When using DMM meters--They draw very little current (millionth's of an Amp). It is possible to read across a "bad connection" with a DMM and read "good voltage". But as soon as you put a small load on the connection, the voltage drops to zero (and why test lights are sometimes better for debugging power connections).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Posts: 4,481Solar Expert ✭✭✭✭
    edited May 23 #6
    Okay, so I guess you bought a clamp meter?

    Are you clamping only 1 wire? They work of fields so if you clamp 2 wires they neutralize each other.

    ...also with some of these new inexpensive meters you set the strength with the dial the select either AC or DC by pushing a button.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • DJuan222DJuan222 Posts: 22Registered Users ✭✭
    let me be more specific

    when set to DC I can read amps off the panels and + wire off MPPT to the batteries

    when i try to read the 12v 300A single unshielded cable from the battery bank to the inverter I get 0

    the setup has worked a year and the single red wire off the car battery reads 0 also on amps

    it seems to be a problem when i try to read from batteries??
  • PhotowhitPhotowhit Posts: 4,481Solar Expert ✭✭✭✭
    Is the inverter on with a load? Perhaps an inexpensive clamp meter wouldn't pick up a minimal draw in sleep mode? @BB. Bill will likely know... Also is the car on, pop on the headlights should work as a load.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • BB.BB. Posts: 27,351Super Moderators admin
    I am unclear if the Inverter is working or not (no voltage on the DC input to the inverter?).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Posts: 949Solar Expert ✭✭✭✭
    You have the DC amps range set to 600A?   Test it when you know you have a few amps of load.  

    Don't attempt to measure volts using the clamp.
  • DJuan222DJuan222 Posts: 22Registered Users ✭✭
    Yes!! I had to let the refridgerator come on then it read a load and It finally gave me 6 amps :)

    question though, to test batteries amps at rest how do you check 100amps?  all of my DMM max at 10amps?
  • BB.BB. Posts: 27,351Super Moderators admin
    What do you mean by "test batteries amps at rest how do you check 100amps"....

    Batteries at rest have no current flow--So no Amps to measure.

    Are you asking how to test a battery to see if a 100 AH rated battery actually 100 AH capacity? Are you trying to figure out if a battery is XX% state of charge?

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