FM CD/Radio wiring

[cardinal07]

I have just fitted a replacement car radio in my motor boat. The power supply for this is routed through the 12v breaker panel which is switched off/isolated whenever I leave the boat. The effect of this is to cause the radio to lose its memory each time I leave the boat, something I find annoying and would prefer to avoid.
Obviously I can remedy this by connecting the radio’s “permanent live feed” directly to the batteries (although a tortuous and long cable run) but are there any pitfalls in doing this, such as excessive battery drain or even fire risk? And, perhaps a naïve question, but if I do this, should I also directly connect the negative cable to the batteries as well? I would welcome any advice. Thanks.

 

[Sneds]

Both wires will need to be wired directly, preferably not to the battery terminal but some other "allways live" point and please, put a fuse in line.

 

[jfm]

I have just fitted a replacement car radio in my motor boat. The power supply for this is routed through the 12v breaker panel which is switched off/isolated whenever I leave the boat. The effect of this is to cause the radio to lose its memory each time I leave the boat, something I find annoying and would prefer to avoid.
Obviously I can remedy this by connecting the radio’s “permanent live feed” directly to the batteries (although a tortuous and long cable run) but are there any pitfalls in doing this, such as excessive battery drain or even fire risk? And, perhaps a naïve question, but if I do this, should I also directly connect the negative cable to the batteries as well? I would welcome any advice. Thanks.

There is no material fire risk assuming the wiring is done well

We cannot comment on battery drain unless you tell us the AH rating etc. On a small say 100AH battery you might notice the drain if you leave the boat 2 months but if you have say 400AH of house battery you will never notice the drain

Some boats have a permanent 12v feed at the breaker panel for clocks and car radio memories. There will maybe also be a permanent 12v feed to the bilge pumps that can be pinched, if you know how to do wiring well

Even if you don't have a permanent 12v feed, you only need to connect the radio's "permanent 12v" wire to the unswitched side of whatever isolator switch you refer to in your post. You do not have to run the wire all the way to the battery and indeed it would be messy to do so. I hate lots of little wires connected directly to the battery posts; it always shouts "bodge!".

The negative would not normally need to be run to the battery. The negative busbar at your breaker panel will be permanently (unswitched) connected to the battery negative and the boat's ground, so just connect the negative wire to the breaker panel's negative and do not run a wire to the battery

 

[SolentPhill]

Both wires will need to be wired directly, preferably not to the battery terminal but some other "allways live" point and please, put a fuse in line.

Doesnt the isolater only break the live side? So there would not be a need to run the black wire, the wire your talking about is the yellow one and as said through a fuse can go straight to the battery. The power draw is very very low.

Check the area at the back of the radio is salt free, as car radios can allow salty air in unlike marine radios that are protected.

 

[cardinal07]

Thank you all for your useful responses. I too hate unidentified wires attached where they shouldn’t be so I’ll do a bit more investigation. Your ideas for the connections have helped and almost certainly will save me dismantling half the boat to run a cable!