What's the risk of bypassing a fuse on my gadget?

[sfalexi]

I bought a J&M Integratr and lots of cables.  When I plug in the 12v adaptor (that replaces the battery compartment) to my bike, the 2 amp fuse (stock size) blows.  When I plug it into my car, it blows.  When I plug it into my other car, it blows.  

So I thought maybe it was the 12v adaptor, so I ordered another one.  And it blows the fuse.  So I thought maybe it was the age of the integratr unit, so I bought a new unit AND another 12v adaptor.  And it blows.

Now to be frank, the unit works great with batteries.  But batteries are expensive.  Even the rechargeables I had need to be recharged every three days for commuting, and every day over the weekend for long rides.  And that's just, well, annoying.  

1) So what's the risk of bypassing the fuse altogether?  Would I blow the entire integratr unit or just risk frying the 12v plug that replaces the battery compartment (I've got TONS of those by now).  I'm wondering what the risk would be if I just jumped the fuse and didn't have one in line.

2) Why's it blowing?  The unit is designed to run off of 12volts.  Could the charging of the battery bumping it up to 14ish volts really be the cause?  

Just really frustrated.  I don't wanna be charging all sorts of batteries all the time.  I was hoping for a plug in system.

[Mac]

the blowing fuse would seem to indicate you have a short in the unit. The short is permitting too much current to flow, thus blowing the fuse. I assume that the fuse only blows when the integratr is plugged in. But you have replaced the unit with new and the problem remains as it does with a new 12 v adapter.

Are there any other cables connected to the integratr when the fuse blows? one of them could be causing the short. Try removing all cables from the integratr and plugging it in, if the fuse doesn't blow, you are on the right track. Then plug the cables in one by one till you find the one that causes it to blow the fuse.
If you have a multimeter, ohm out the cable to find the short. Unless its obvoiusly damaged the short will most likely be in the connectors.

[zer0netgain]

the blowing fuse would seem to indicate you have a short in the unit.

+1

Generally, the fuse has nothing to do with voltage but with amperage.  A fuse is set for the max load a device should be drawing.  Normally, the fuses are included to compensate for the fact that most people tie into a power supply on a much higher amp fuse (e.g., my Garmin 12v adapter has a 2A fuse but it's plugged into a 12v socket that's on a 10A circuit.

If the fuse on your device keeps blowing, something is either wrong in the wiring of the 12v adapter OR you have a short in your device that's drawing more than the fuse will allow for.  That it works fine on batteries only means the batteries can supply the demanded amps, but if this should not be happening at all, odds are when it's running on batteries, damage is being done.  That, or the manufacturer had a brain fart and used a standard 12v adapter which might have come from the manufacturer with a smaller amp fuse than should be in place.  If it comes with a 2A fuse and should have a 5A fuse, then it'd be safe to switch out the fuse with one of the correct capacity.

[RBEmerson]

The answer to your question in the subject is easy: you risk an electrical fire which could well torch your bike.  Pump a bunch of amps through a skinny wire, it'll heat up and, if you're unlucky enough, set the insulation or something nearby on fire, and from there things go downhill.  Flame near a gas line or bit of oil...?  Ooooohhhh... Not Good.

Do it right or don't do it.  'Nuff said.

[bomber]

Agreed -- there is something wrong somewhere -- the meter will help you figure out where . . . bypassing or increasing the size of the fuse is always a bad idea, and, often, leads to great excitement and humorous anecdotes (for others).

[Mac]

Agreed -- there is something wrong somewhere -- the meter will help you figure out where . . . bypassing or increasing the size of the fuse is always a bad idea, and, often, leads to great excitement and humorous anecdotes (for others).

Like the guy who replaced a fuse in his cage with an unfired .22 bullet. Almost bled to death before he got to the hospital.

[sfalexi]

It just ticks me off that I've tried two units, three 12v adaptors and three vehicles, and EVERY combination of the above and it ALWAYS happens.

I'm just gonna use rechargeable batteries or get the battery designed for the system (and hope THAT one doesn't short out!)

Alexi

[Mac]

It just ticks me off that I've tried two units, three 12v adaptors and three vehicles, and EVERY combination of the above and it ALWAYS happens.

I'm just gonna use rechargeable batteries or get the battery designed for the system (and hope THAT one doesn't short out!)

Alexi

Is there anything else that attached to the unit except the 12v adapter?  If there is, unplug it, then connect power and see if the fuse blows.

[bomber]

It just ticks me off that I've tried two units, three 12v adaptors and three vehicles, and EVERY combination of the above and it ALWAYS happens.

I'm just gonna use rechargeable batteries or get the battery designed for the system (and hope THAT one doesn't short out!)

Alexi

then I would suspect that the problem is not with the units -- what else is in common (other than yourself)?

[zer0netgain]

That would be odd as a short should affect the circuit BEFORE the problematic fuse.

Is there a way to omit the fuse (or use a larger capacity one) and use a multimeter to see how much amps the device draws at max?  Maybe it's just a tad more than the default fuse and a slightly larger capacity fuse would solve the problem without threatening harm.

What's that amp output from using batteries (type, capacity and number of batteries)?

[Walker]

That device is blowing 2A fuses?  There is no way it is drawing more than 24W (12V X 2 Amps = 24 Watts) if it also runs on batteries.  There is something else wrong, either with the unit, or with your plug.  

DO NOT try to bypass the fuse.  DO NOT try to install a larger fuse.  DO get your hands on a multi-meter (and maybe someone who knows how to use one if you don't) and try to investigate the problem.