How do I check how many amps a device is pulling?

[sfalexi]

I've got the J&M Integratr and the 12v adaptor keeps blowing its fuse.  Put a new fuse in, plug it into bike, turn on unit, and nothing happens-fuse is blown.  I've tried two separate main Integratr units and 3 12v adaptors all on my bike, in my wife's car, and in my car, and it's the same thing.

It blows a 2 amp fuse.

How can I see just how many amps it's pulling and when?  I have a sneaky suspicion that something is up with the design that pulls a large amount for a split second when turning on, and then "settles in" to operating norm (does that sound feasable)?

I have a multimeter (not quite sure how to set it up), and plenty of 12v adaptors to cut up and test.  What would be an efficient way to troubleshoot it?  Thanks.

Alexi

[DRam]

How is the 12v adapter wired into your electrical system?  Are you sure polarity is correct?

If you are positive everything is connected correctly, contact the manufacturer, explain what is happening, and see if they have any suggestions.

 

[sfalexi]

The 12v adapter is plugged directly into a cigarette lighter.  It comes with it's own plug and fuse inside the plug.  So the polarity is definitely correct.

I contacted the manufacturer months ago who told me I could send it back and they could take a look at it for 80 dollars.  So I'm trying to avoid that (it is out of warranty).

Alexi

[Mac]

Your multimeter should have an amperage setting where you can measure current in line. There are two problems with that though, usually the current measured must be under 1 or 2 amps , second, you must put the meter in line. Which means you would have to disconnect the hot, non-ground, wire to your cigarette lighter plug, put one lead of the multimeter on the wire you just disconnected and the other to the terminal you disconnected the wire from.

You might also go to radio shack or a good auto parts store to see if either sells a amperage meter/gauge, it is the same thing as the multimeter, but should be good for much larger amp loads. I don't think they'd be all that expensive, under 10 bucks. you would wire it in the same way I described for the multimeter.


If, as you speculate, the circuit is momentarially drawing a larger load then for what the fuse is rated, you should be able to substitute a larger value fuse with no damage to your equipment.

[Mydlyfkryzis]

Or find a slo-blo fuse. They handle an over-current for a short amount of time.

[Andrew]

put a 3 amp fuse in, or maybe a 5 amp, just be aware you might let the smoke out.

In all honesty if it is popping the fuse rating that it came with and the cable is not grounding out, your integrator has a problem (internal short)

[sfalexi]

Tried a different 12v adaptor I found around, and it's working (so far).  I DID buy some slo-blo fuses as recommended.  So far so good (crossing fingers...)

Alexi