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Help with a car lighter inverter

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    #41
    Re: Help with a car lighter inverter

    What's on the USB board, does it have its own converter? (my USB port on my AC inverter has its own converter, so I could just feed in 12V from the car straight in, so it would make it easy to figure out what needs to be fed in.)

    This board sure looks like it has seen its days...

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      #42
      Re: Help with a car lighter inverter

      In these pictures you can see the board with the USB ports and the unattached red cable on the left. On the right you can see a connector with a pair of smaller red and black cables detached from other board. That board measures about 3\4 inch long, as you can see in the last picture, and is only a status light with the brand logo. For that one I can use the diode testing mode in my multimeter to find out the polarity of the diode. I hope this helps.
      Attached Files

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        #43
        Re: Help with a car lighter inverter

        I only see a couple of caps and an IC, besides the ports.

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          #44
          Re: Help with a car lighter inverter

          Ah yes, so it does look like the USB board has its own regulator much like the one I have, so likely the input hooks up straight to the 12V input, just tap off it anywhere. Likely it's a MC34063A based regulator (can't read the IC or enough of the back side of the PCB is showing) and is its own switching buck regulator. I suppose the LED indicator lamp is lit from the same tap. Finding the resistor on that board would be another good sign as to how many volts should go in.

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            #45
            Re: Help with a car lighter inverter

            Yes, the IC has written on a series of numbers and letters: 63API before the "6" there are what seems to be three numbers which are very faint. I looked up the visible part of the code and found only a site selling ICs with errors "save buying IC with typos" It says. Maybe this is one of those since the first numbers are not readable so easy. The most I can make is a "300" but it could be wrong, below is a picture, I'll try to get the complete code later when I get home, thanks.
            Attached Files

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              #46
              Re: Help with a car lighter inverter

              I was able to see the complete code on the IC, It is: 34063API as you can see in the picture I attached to this reply.
              Attached Files

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                #47
                Re: Help with a car lighter inverter

                Yup, that's the ubiquitous MC34063 allright. So just need to connect the + wire (probably the red wire, though need to see tracks on back of the MC34063 board to be sure) to somewhere after the main fuses/switch and black to GND (again, need to view board. Pin 4 of the MC34063 should be connected to whatever is connected to GND as a double check.)

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                  #48
                  Re: Help with a car lighter inverter

                  Hello guys, I'm back! I'm so sorry to take so much time from my last post, these days have been very hard. I've been fixing other stuff around the house, gas range, clothes washer

                  Now, yesterday I put back together the Inverter and found it showed a blue/purple light in the inverter's brand logo but then it turned off on itself and toggling the switch on or off showed no change. Then I tried unplugging and plugging back and the only two LEDs, purple/blue on the logo and the status led, both flash the moment I plug the inverter. I'm not plugging directly to a car lighter socket, I'm using a home to lighter plug converter. It's a power converter to convert 120v AC to 12v DC (5.25amps) and noticed that, as soon as I plug the inverter, the adapter's status light dims and starts buzzing and the inverter starts buzzing as well. I can say the the buzzing in the inverter comes from the general area around the transformer.

                  Bellow is a picture of the power converter I'm using and its box. Any guess as if the transformer is bad or should I check other components? Thanks again.
                  Attached Files

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                    #49
                    Re: Help with a car lighter inverter

                    that is a power supply not an inverter .

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                      #50
                      Re: Help with a car lighter inverter

                      I think he's using the power supply to power the inverter so he doesn't have to test in a car or whatnot. In any case it sounds like something's still shorted, check the other MOSFETS to make sure there are no shorted units.

                      Oh, and better yet, measure the voltage of the PSU/current draw of the inverter for more clues as to what's going on... ideally the inverter should not be drawing much except for the first moments as it charges the capacitors. Should not be more than 1A or so, and the PSU voltage should not drop below ~12V ...
                      Last edited by eccerr0r; 10-16-2018, 05:03 PM.

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                        #51
                        Re: Help with a car lighter inverter

                        inverter will want plenty of power especially starting up . those things run hot . car fuses are generally 10 amps and might blow with my 150w modified square wave inverter so upped to 15amps no problem
                        that supply is only 5.25 amps according to the box .
                        running an inverter from a 12v supply running from mains supply is not how it works in my book ...
                        ok got over my way of how its done and now wondering what size fuse is fitted in the inverter as i would hope the supply can supply at least twice that value to have some overhead short term . . that damn thing of mine whines like hell trying to start up on a low battery ..
                        Last edited by petehall347; 10-16-2018, 05:12 PM.

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                          #52
                          Re: Help with a car lighter inverter

                          eccerr0r is correct, there's only one car here and it will not be available for a few days so I used the converter, maybe I can test in car today or tomorrow. As of the testing, you got to help me on this too, lol, I know the basics of my multimeter but I just use it mostly for diode and resistors testing. By testing for draw, do you mean testing amperage of the converter/ power source for the inverter or the inverter? If you refer to the converter, should the inverter be plugged? How should I do the test, should I place the black lead to the heat sink on the transformer and the red anywhere else in the AC area?

                          petehall347: The inverter has a 20 amps fuse, before it broke someone put a 25a fuse so that may have damaged the MOSFET I replaced.

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                            #53
                            Re: Help with a car lighter inverter

                            you need at least a 20 amps supply then to run the inverter .

                            Comment


                              #54
                              Re: Help with a car lighter inverter

                              You need a 20 amp supply to run the inverter at peak load. The inverter without a load should at least start up with a lower supply after it charges the capacitors. The 80W inverter I ninja posted about in this thread has a 7.5 ampere fuse, and I was able to run a 4W 120VAC night light with the inverter on my 2A power supply.

                              Back to the original question, the problem you might run into is that since the power supply is fully enclosed, you can't measure voltage, so likely you'll need to run the inverter without its case so you can measure key figures. Do not run with a load; if you must, a 4W night light at most.

                              First off would be voltage drop across the inverter. Measure the voltage from + to - as it comes into the main switch and after the switch in voltage mode. Make sure it's 12V before the switch when the inverter is off. Then turn the inverter on.

                              If it drops down to less than 4 V or so, you still have a short. Do not pass go, do not collect $200, disconnect and go look for the short.
                              If it fluctuates around 7-12V the power supply appears to be overloaded. In this case either the inverter is drawing more current than it should be, or the PSU is bad.

                              Current measurement needs to be run inline with the power source if you have an inline multimeter (versus a DC clamp ammeter). If you don't have a set of gator clip wires and some way to access the contacts on the power source, this can be hard - but you can work around this by simply removing the fuse in the inverter, and connecting the multimeter probes into the fuse contacts. You should be careful as you may generate sparks if the device under test is still shorted; otherwise you would only get a spike for the initial capacitor charge, and current should taper off to no more than an ampere with no load on the inverter. My 80W cheapo inverter draws like 500mA or so with no load.

                              As a word of warning and caution: Never leave your multimeter in ampere testing mode when not using it, especially probes plugged into the ampere measurement jacks. You _will_ forget one day and could do tremendous damage to something, whether it the circuit or yourself.

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                                #55
                                Re: Help with a car lighter inverter

                                Excuse my late response, I have plugged the inverter to the car's CIG lighter outlet to test it. It blew the fuse on the car's fuse box. I don't remember if it did blow right when I plug it or as I turned the inverter on but I had no load on the inverter. The car has TWO outlets: Both have a 15 Amps fuse each but the manual states not to use for anything I've 12V 10Amps. Luckily I have some more fuses on hand to try again.

                                When you ask me to measure voltage drop, before and after the main switch,Do you mean some kind of IC? It seems to me you don't refer to the physical On/Off switch but need to be sure of what I do here ^_^

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                                  #56
                                  Re: Help with a car lighter inverter

                                  Well, that makes it clear...something's still shorted.
                                  You may need to use a dim bulb tester to slow down your fuse consumption rate. Instead of using an A19 bulb, a car bulb will do, perhaps an incandescent festoon lamp which tends to be around 12V/1A/12W which should be sufficient to prevent fires and additional damage to the inverter.

                                  When I say voltage drop, it simply means the voltage across the two points. Normally there would be a minimal voltage droop at no load, the voltage drop across the inverter would still be around 12 volts as no current is flowing. But there's a short - now the voltage can't rise up to 12V anymore and the "drop" would be much less than 12V, forcing the fuse to take the drop and killing itself to protect the whole circuit from immolating.

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                                    #57
                                    Re: Help with a car lighter inverter

                                    What do you mean by INLINE multimeter? Mine is that in the picture I include below. It has no clamps, just pointy leads. When you say there's a workaround and going to the fuse contacts, I get it you mean to place the leads in both contacts of the fuse port, Am I right? The fuse port is on the cable, it's between the end that goes to the car lighter outlet and the inverter.
                                    I included a picture of the fuse port as well as one of my multimeter.
                                    Attached Files

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                                      #58
                                      Re: Help with a car lighter inverter

                                      So I should getBy BULB TESTER, you mean soldering leads to the bulb you specified and one end to a switch and so on? Or do you mean a probe like the one in this (https://www.amazon.com/Professional-.../dp/B003UHNMMS) link?

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                                        #59
                                        Re: Help with a car lighter inverter

                                        try measuring ohms on inverter input when inverter switched on ..there is a short . might be after this point but good place to start .
                                        p.s i see the fuse is 20 amps .

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                                          #60
                                          Re: Help with a car lighter inverter

                                          The "dim bulb tester" is an ad hoc tool people make. It's just a light bulb that you jury rig into the circuit in lieu of the fuse. It's conductive enough to let power pass, but if the device is shorted, instead of the device or the removed fuse taking damage, the light bulb lights up brightly, signifying a short. The light bulb "car tester" probe likely is not conductive enough to pass enough current to do much testing in this manner.

                                          And yes you can stick your probes into the fuse socket instead of the fuse to test current draw. As your inverter is still shorted as witnessed by a burnt fuse, there's no need to continue to test in this manner, you'd likely cause damage to the circuit or the meter if you tested this way - you have to look at the inverter.

                                          BTW usually those ATC/ATO fuses have a little metal exposed at the "handle" side of the fuse that you can use your sharp multimeter probe to measure voltage before and after the fuse. People often use these to check the fuse without removing the fuse.

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