12V Mystery

Cpyder
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My amps weren't receiving enough voltage (don't flame, I know voltage doesn't flow) so I tested my car with a multimeter and found that right in front of the in-line fuse holder it was above 12 V but immediately after it was 6V. (this fuse has worked previously before) but how can a fuse lower the voltage??? Buying a new fuse holder and 100A fuse took care of the problem.

 
AGU glass cylinder fuse ?
I have seen those do that before.
Yep. It was a glass cylinder. That's very weird. I'd figure it could only restrict current flow not alter the voltage.

 
Yep. It was a glass cylinder. That's very weird. I'd figure it could only restrict current flow not alter the voltage.
its basically a resistor with a known amperage rating that it will fail at. Voltage drops over pretty much all fuses, except really large ones, and even then you have drops because of the connections. Its just like running a piece of 4 gauge wire 1000' your going to have a voltage drop across it, same concept larger scale

 
Yep. It was a glass cylinder. That's very weird. I'd figure it could only restrict current flow not alter the voltage.
I think the filament cracks at the end somewhere... still passes some current but has a high resistance so drops voltage drastically. The first one I saw was showing 5v on the other side!

 
the fuse filament is soldered on both ends...usually due to a bad connection...like an arcing connection...will cause the solder to heat up and melt...it is best to switch to ANL or mini ANL fuses if you want the best quality car audio fuses...the big blades arn't too bad but most of the fuse holders for those arn't worth a dam....

 
glass AGU fuses are the devil. at least the ones that are made for car audio use. most of them are built poorly and usually need to be swapped after a year of use (in my experience)

the ones that come inside some of the marine electronics equipment that I install at work seem to be built much better, and I not seen that type of failure like the car audio versions.

i wont use anything but Maxi or ANL style fuse in a car install

 
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