Reply With QuoteIn this case the red wire is your memory wire. If you hookup the black to ground and the yellow+red to your positive wire it will work.
Hi gents, some help would be appreciated!
I've just attempted to wire a stereo and ultimately didn't get power to it.
My boat is a single battery with engine leads and leads to a ground block and fuse block. Now, my understanding was that I could simply take power from the lead going to fuse block (before it arrives at the fuse block) and take ground from the anywhere from the ground block... I connected the stereo this way and could not turn it on.
Note:
The stereo has an inbuilt 15amp fuse
& the power to the fuse block has a inline fuse (10amp) at the battery... could this be the problem and my stereo downstream has a 15amp fuse?
In terms of boat stereos, I understand the yellow wire to be 'memory', which I don't need so I ignored it and used the stereo's red wire '12v switched' instead which I expected would suffice as power. In my stereo's manual the yellow is called 'power - 12v ignition'... Should the stereo work by connecting ONLY the red (aka 12v swtiched) ??
Does anyone have some adivce on how I should do it, beairing in mind that I don't want to use the memory lead
In this case the red wire is your memory wire. If you hookup the black to ground and the yellow+red to your positive wire it will work.
You need to connect both red and yellow to +12V. The red is the power supply wire (this supplies the bulk of the power) and the yellow is the 'on' wire, which is just a signal to say 'switch on'.
As for fusing arrangements. The 15A fuse at the stereo does nothing to protect against short circuits in the wiring running from battery to fuse. Never wire anything direct to the battery without a fusible link or fuse in series with it at the battery end.
Sometimes its better to look like an idiot than to open ones mouth and remove all doubt.
I fitted a stereo to our van and had to connect the red and yellow to posative and black to negative.
Scott
My stereo used yellow as battery/memory with a 15 amp fuse (obviously the main power supply for the unit + backup) and the red was just for ignition switch as a trigger, it only had a 500ma fuse so it's not drawing any current on the red. but you need to power both yellow and red for the radio to turn on.
15 amp fuse on the stereo means your upstream 10 amp fuse may nuisance blow if you turn the volume up too high. BUT you should NOT replace the 10 amp fuse with a higher value unless you know the wiring downstream can handle the current.
if you connect closer to the battery than the 10 amp fuse then the 10 amp fuse won't have any bearing on the radio.
I did at one point connect both yellw and red wires at the same time without getting power. The lead is definately good so I'm wondering if the ground connection I made is dodgy.
also if I do Connect both yellow and red wires how do I stop the power draw for te memory presets ?
Cheers
Originally Posted by Barrykrocker
I had to connect both power wires when installing my stereo, I wired the memory wire through a master switch to stop any power draw when stored.
Pretty sure the memory is only for the clock so not worth worrying about or do the switch thing if you store the boat for long period of time. Take a wire from the posative to the stereo , pass it through a nice little neat toggle switch mounted next to the stereo then join the red and yellow from the stereo into the other side of the switch. Or if you have a bank of switches for bilge or lights run it through a spare one of those is avaliable.
Scott
Simple wiring diagram below (very basic). If it doesn't work then you have bad connections, blown fuses or perhaps the unit is stuffed or needs a security code.
Switching off either the master switch (if you have one) or the radio switch will completely disconnect the stereo and it will have zero current draw.
BTW, on some audio equipment there is a diode inside that protects against reverse polarity (wires connected backwards). This diode shorts out the incorrectly connected power and blows the fuse (its called crow-bar protection).
Sometimes the diode itself goes short circuit after the wires have been connected backwards and it will then keep blowing the fuse even if the wires are connected the right way around. So check the fuse in series with the stereo (and any other fuse in the circuit).
Hope this helps.
Sometimes its better to look like an idiot than to open ones mouth and remove all doubt.
Hmm, how do I determine whether the wiring can handle the current?!
Cheers,
Your diagram seems to imply that the inline accesories fuse is a total of the ampage used cownstream. Is this the convention?
The short answer, there is no convention I know of, it depends on the wiring capacity. I picked 30A as a fuse that will protect most wiring looms and still handle the load (I would be surprised if your stereo drew 15A).
Some of the guys in the trade will be better placed to tell you the conventional values to use for wiring and fuse ratings. There was a whole thread a while back about wire sizes etc.
The accessories feed fuse is rated for the capacity of the wiring going from the battery to the switch panel. This fuse is to protect the wiring from catching fire in the case of a short at the far end (or anywhere in between). Likewise the wiring must be rated high enough to handle the fusing current (not just the load).
Fuse ratings are a little hard to explain. A fuse doesn't magically fail at its rated current. Instead there is a time curve that says how long a current exceeding the fuse rating has to be present before the fuse blows. A fuse must rupture with a current 130% of its rating, but it can take up to 2 hours to do so. Less than 130% it doesn't have to rupture at all. With 200% current it must rupture within 1 sec.
At 100% rated current some fuses glow red hot and can melt or damage the fuse holder. A fuse at 130% can glow very brightly for quite some time and start a fire if in contact with flammable material.
So... the fuse to the wiring loom must be rated high enough to run all the accessories, plus an excess amount so the fuse isn't excessively hot at maximum load. And it mustn't be rated too high that the wiring isn't adequately protected.
Sorry I didn't give a simple answer.
Sometimes its better to look like an idiot than to open ones mouth and remove all doubt.
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