Radio and Batteries

[Matt Dingman]

I am going to rewire my boat this fall. It's a 16ft Crestliner right side console. There's a mess and it needs cleaned up. I want to run everything to a fuse block and then to the battery. What I want to know is how does one hook up the radio without losing the presets everytime you shut off the key. Also, if the radio has 4 speaker outputs and I have but 2 speakers, what does a guy do with the other 2 sets of wires? Also, how do I go about hooking up a second 12volt battery as a backup without creating a 24volt system. I just don't want to drain one battery then have to switch to a second one in the middle of the lake. Please refrain from using big electrical terms like "parallel and series" I don't know enough about it to know what it's called. I do know more thatn enough to be dangerous No seriously, I have an electrician friend who will help, but this is marine not industrial so I feel dumb asking him such mundane questions I feel I should know the answer to! Thanks anybody!
Matt

 

[woody66912]

Re: Radio and Batteries

just keep pos to pos and neg to neg on both batteries don't jump pos to neg between two bat ties that's 24 volt. run at least 8 gau from batteries to helm fuse block as for radio pre sets it can't be done. don't run radio power supply to a purple wire this is key on power. just tape off each speaker .you know when you messed up when you let the smoke out of the wries.trashdady has great links to wiring diagrams.i'am not that proficient with that sort of thing.

 

[Silvertip]

Re: Radio and Batteries

This is how you do a dual battery configuration using a battery switch.

This is the simplest yet most versatile setup. If you don't want to use a battery switch, or understand how to use it, then a simply paralleling (yes I know) two batteries may work but you still lose versatility and can still run down both of them leaving you still stranded. I highly recommend a battery switch. If that's not your bag -- here ya go with a parallel system.

To avoid losing the radio presets, there is a "station memory" wire (yellow I believe) that must be wired to a constant source of +12V. That wire keeps the clock and station memory alive when the key is off. Right now that wire is probably tied to the same spot as the normal +12V power wire (red) for the radio. If you have four speaker outputs, but only use two, connect the speakers to the Left Front and Right Front, or Left Rear and Right Rear. Leave the other outputs unconnected. Turn the Fader control so all the power goes to the front or rear depending on which pair of outputs you are using.

 

[woody66912]

Re: Radio and Batteries

matt.if you wire the memory wire hot it will drain your battery in one week.radios will pull 5 milliamps .we tell our customers it's best to just put the power supply to radio on a switch.

 

[littlebookworm]

Re: Radio and Batteries

There is some debate as to whether or not to hardwire the memory (usually yellow) wire of the radio to a positive connection or not. Some people, such as the previous writer, say not to do so because it will eventually drain your battery. True. Others say do it because the drain is slight and you'll use the boat a week later, thereby recharging your battery. After all, your car has it hardwired and car batteries never die from a memory hookup. Also true. The choice is yours. On my boat, I'm leaving it connected; but I also am set up for shore power and an on-board battery charger to keep my batteries charged. Your choice. Good luck and safe boating. Hy

 

[metriccrescentwrench]

Re: Radio and Batteries

it will drain your battery in one week.radios will pull 5 milliamps


5 milliamps for one week is 0.84 amp-hours. A normal starting battery has a capacity of at least 75 amp-hours, so that 5 mA draw is pretty insignificant. Besides that, I'd bet that the radio memory draws less than 5mA. I won't go so far as to say that for fact, but I'd be willing to bet an "I told you so".

 

[PondTunes]

Re: Radio and Batteries

Hook it up constant, unless resetting your stations doesn't bother you. One solution if you normally leave your battery switches in the on position is to connect it to the common post on the battery switch. This way it will stay on unless you move the switch to the OFF setting. This works well for boats that stay on the water at a dock and are trailered rarely or just pulled out for the winter. It will take a very long time to drain your starting battery as shown above with just the radio memory.

There are some radios coming out now that keep memory with zero current draw but they would require changing out your radio.

 

[BMOLCHANY]

Re: Radio and Batteries

Many new radios do have this. I just put a new AM/Fm as well as a marine bank one in and both have this feature.