Testing an Inverter

Discussion in 'General Electronics Chat' started by Gdrumm, Jan 2, 2015.

  1. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    Please see photo.
    Should I be able to test an Inverter using a 12v DC Regulated Power Supply?

    I get a short beep when I turn on the Inverter, and the red light flashes, but I don't see any voltage showing up on my meter.

    Must I test it with a Car battery?

    Power Supply says 13.8v DC, 2.5 amps, 60 watts.
  2. debe

    Well-Known Member

    Sep 21, 2010
    I would use a battery as the start up current is probably more than the powersupply can handle.
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Oh, I dont know, there are power supplies:
    and then there are power supplies:

  4. wayneh


    Sep 9, 2010
    I think I saw a voltage when I was playing with my inverter but it was not a reliable value. The voltage was steady once a small load was applied. I think I used a 7W nightlight bulb.
  5. wayneh


    Sep 9, 2010
    Hahaha, including the ruler is a nice touch. Reminds me of eighth grade. :rolleyes:
  6. Lectraplayer


    Jan 2, 2015
    I've had so much heartache trying to test on the second power supply (type) shown, I wouldn't try it without at least a gel cell. So many protection circuits to foul the diagnosis up.

    I also wouldn't trust my measurement unless I put a load on it. ...say, a 70 watt HPS street lamp? :D
  7. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    Good tip about the load.
    Using a 75 watt bulb, I tested it on my truck battery (truck not running).
    It turned the light on for a split second, and beeped, then shut off.
    I tried it again, with truck running, same result.

    Earlier on, I found and removed an open thermal fuse mounted to the side of the box, and I twisted the two wires together. Once I fix the unit I'll replace the bad thermal fuse.

    No signs of blown components, and I don't see a standard fuse.
    Do the symptoms signify anything in particular?

    Last edited: Jan 3, 2015
  8. ian field

    Distinguished Member

    Oct 27, 2012
    I had a UPS beep and go straight off because of high internal resistance in the battery.

    On the Optimate battery conditioner, the battery charged normally and eventually progressed to the green LED battery OK indication - with a new battery the UPS worked fine.
  9. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    I am certain my truck battery is good.

    I've checked probably 20 components on the board, including caps, diodes, and Zeners.
    So far I've found 3 Zeners that show voltage both ways.

    I think this project just became too labor intensive.

    For $20.00 (and 20% off that with a coupon), my friend can buy a decent Inverter at Harbor Freight.
    Shucks, I've got 2 or 3 of them laying around.
    I can just give him one if he really neeeds one.

    Thanks for all the input.