Radio blows fuse while running

[liquidlew]

Man, I love this forum, I'm learning a ton just feeding off everyone's Q&A! Ok, I put in a new Sony am/fm/cd player and it works fine w/ engine off, however while running the fuse blows within 5-10 minutes every time. Voltage reg? Where is that located on a 1989 Sea Ray 4.3 Merc? Repair shop replaced volt meter ( is that the same as a regulator?) last year so it's somewhat new. Oh, the radio is not a "marine" radio, I got it at Walmart in the auto dept. I know they aren't sealed for moisture so I'm taking my chances but are they different electronically? Could this new high power unit be drawing too much juice for this old system? The old original radio was what, 15 watts? This new one is 200 watts. Thanks bond-o for the welcome btw! And thanks for the advice to everyone on my last Q, I got the cast iron manifolds and risers.

 

[Haut Medoc]

Re: Radio blows fuse while running

The voltage regulator is in the alternator & has nothing to do with the volt meter......
I'd look at the size of the fuse, for starters......​

 

[THE BEEF]

Re: Radio blows fuse while running

Check the manual and see what the correct fuse size is.
That 15 watts is output to the speakers I believe.
A 200 watt system will require more input amperage.
at 12 volts. If the fuse is rated to low it will burn out.

 

[Bondo]

Re: Radio blows fuse while running

Ayuh,...... You're Welcome.....

Which fuse is Blowing,..?? What's it's rating,..?? Is this the fuse that came with the new radio,..??
Where did you tap in for the power for the radio,..??

 

[Don S]

Re: Radio blows fuse while running

Moving to the Electrical & Electronics forum.

 

[liquidlew]

Re: Radio blows fuse while running

Oops, next time I will go to the Electrical section for stuff like this. It's the inline fuse supplied with the new unit and it is a 2 amp fuse. I tapped into the supply the old radio came off of. Radio works fine with the engine off, while underway the fuse will blow somewhere after about 5 min.

 

[tashasdaddy]

Re: Radio blows fuse while running

does the ingition key have to be on for the radio to work? if so get it off the motor circuit. power from battery.

 

[liquidlew]

Re: Radio blows fuse while running

No, the key/ign. is off, but the Accessory switch has to be on to run the radio.

 

[jlinder]

Re: Radio blows fuse while running

2 amp fuse with a 200 watt radio? 2 amps at 12 volts is 24 watts max. Something is wrong.

Check the manual to see if it should really be a 2 amp fuse.

 

[Boatist]

Re: Radio blows fuse while running

I agree 200 watts at 12 volts takes 16.6 amps. If you keep the volume reel low it might run for a while. Probably should be at least a 20 amp fuse.
For a 20 amp fuse you need a wire size of 12 guage or more. Both wires whould be 12 guage or more. Check your manual it should tell you the wire size and required fuse size.

 

[D-squared]

Re: Radio blows fuse while running

Boatist and Jlinder are spot on.

Can you say electrical wire harness fire? You need to route a pair of 12 gauge wires to the elerical main and fuse it appropiately. When Boatist says "both wires" he is referring to both the power and ground wires.

If you are cranking up you tunes that fuse is saving your bacon.

One other thing to watch for, if the new voltage meter is accurate enough to measure it, you should be around 13.8Vdc when running under power. It would be wise to find a buddy with a handheld DMM to check actual voltage levels with the motor running.

Don

 

[liquidlew]

Re: Radio blows fuse while running

Thanks guys! I guess old boats are a little different than cars where you can put in any old hi power radio and go. I will definitely take all of your advice. I think my elec system is good, my volt gauge is on #14 when running, but I will check it against a meter as well. Thanks!

 

[Silvertip]

Re: Radio blows fuse while running

That 200 watt output is not a DC signal but rather an audio signal and is specified in a number a ways. It may be RMS, Peak, Peak-to-peak etc., and to complicate it even more, it may be specified into 4, 8, or 16 ohm loads. Even a 600 watt locator has a small fuse.

 

[rocket1968]

Re: Radio blows fuse while running

I did the same thing and used the old wiring that once powered an OEM car radio and needed to run new power and ground to get the performace I wanted. I am upgrading this year again and will be putting in a separate fuse box for the radio and a switch that is not tied into the ignition.

 

[Boatist]

Re: Radio blows fuse while running

All the radios i have seen have been rated in RMS Watts. Also will also give you watts per channel in RMS watts.

 

[jlinder]

Re: Radio blows fuse while running

Silvertip is right. 200 watts of audio is not the same as a 200 watt light bulb.

Some amps are rated at RMS which is the power it can deliver on a constant basis, some at peak, which is a power it can deliver for short audio peaks only.

This gets even more complicated when you start asking about the audio itself. For example, audio with a big dynamic range, like classical music can have an average power that is only 15% of the peak levels.

This is opposite of a radio station where they compress the audio and limit the peaks so they can get their sound to be the loudest. I have seen audio meters on radio stations that just seem to slightly quiver at 95% - 100%.

All that being said, the wisest move is till to just wire for the full rating and leave it at that.

BTW - if you are running it at full 200watts you may want to consider voltage drop to get the best performance.