FM Radio/CD player connected to starter battery

[BBC16385]

I have a 1997 P 42. The FM/CD radio is connected to the starter battery in a way that will prevent the radio from losing presets and other memory settings when the batteries are shut off. Apparently the radio is entirely powered through the starter battery. I left the boat on for a week plugged in and the battery switches on and came back to find the starter battery dead. Totally. It does not get charged by the AC battery charger.

Has anyone found a way to move the radio power supply from the starter battery to the house bank?

 

[Tally Ho]

I thought newer stereos had a ram memory or a small battery to keep the presets, etc.

As far as I know, my radio is not connected permanently to the battery ( I have a breaker on the panel that I use to turn it off when I leave the boat. And when I return and turn the breaker on, the radio is in the exact same state as when I turned it off.

My radio is certainly not cutting edge new. I have owned the boat for 8 years, and I think the radio is at least 5 years older than that (maybe a lot more….has a CD player built in, and no BlueTooth ;-).

Greg

 

[smokey73]

@Tally Ho. check the wires from the back of your battery. If your radio keeps the presets when the breaker is off then there is likely a small wire (possibly yellow or red) that runs to an always hot lead somewhere. Mine is like that - has a breaker for power to operate the radio and a small hot lead connected, in my case, to a house battery "always hot" connection.

@BBC16385 With that said, those radio presets take very very little power and most likely would not drain your start battery over a week or even several weeks as long as your battery is in good condition and was fully charged when you left the boat even with no charging current going to the battery. Is there a breaker for your radio that shuts off 12V power to the radio itself. If not, was your radio left on when you went away. I would not expect the "preset power" load to be enough to drain your battery so I'd be looking for some other parasitic load.

Larger question is why the AC charger does not charge your start battery? On a boat of that size and vintage, I would fully expect the battery charger to either allow two charge outputs or a charge relay to be installed to charge the start and the house batteries from the AC charger. That may need to be corrected to make sure your start battery is always topped off.

 

[Davidasailor26]

What model radio?

This is the power wiring diagram for my PolyPlanar radio -

They show the switched red line on the same battery as the always-on yellow line, but I doubt there’s any reason it needs to be.

I’ve measured the parasitic load from my always-on circuits, which are my solid state bilge pump switch and the stereo memory. Combined they’re 11 mA, so it would take about 100 days to take 25% out of a single battery. But if the radio were left on and connected to the same battery that would probably be about 2 amps, so one day would probably be about all you’d want to run it.

@smokey73 also makes a good point that the charger should have kept up with the load in any case.

 

[BBC16385]

I have a breaker for the radio on the panel. When I turn it off the radio turns off but somehow a flow of power from the start battery continues to the radio to maintain the presets. It is a small amount of power but enough to bring the starter battery down several tenths of a volt over a couple of weeks of sitting. From 12.6 to 12.1.

The bilge pump is wired in a similar way. It is never really off.

I thought newer stereos had a ram memory or a small battery to keep the presets, etc.

As far as I know, my radio is not connected permanently to the battery ( I have a breaker on the panel that I use to turn it off when I leave the boat. And when I return and turn the breaker on, the radio is in the exact same state as when I turned it off.

My radio is certainly not cutting edge new. I have owned the boat for 8 years, and I think the radio is at least 5 years older than that (maybe a lot more….has a CD player built in, and no BlueTooth ;-).

Greg

 

[BBC16385]

The radio is a West Marine discontinued radio from five or more years ago. My connection is like yours in the diagram. But I have a cable coming off the battery terminals, no small wire. Where is the connection in your diagram? Behind the breaker panel?

What model radio?

This is the power wiring diagram for my PolyPlanar radio -
View attachment 209358

They show the switched red line on the same battery as the always-on yellow line, but I doubt there’s any reason it needs to be.

I’ve measured the parasitic load from my always-on circuits, which are my solid state bilge pump switch and the stereo memory. Combined they’re 11 mA, so it would take about 100 days to take 25% out of a single battery. But if the radio were left on and connected to the same battery that would probably be about 2 amps, so one day would probably be about all you’d want to run it.

@smokey73 also makes a good point that the charger should have kept up with the load in any case.

 

[BBC16385]

The generator and the engine alternator charge the start battery. When plugged in the charger only charges the two group 8 D batteries. Xantec Freedoms used to have a "trickle charge" for starter batteries but that was eliminated some time ago. I have a radio breaker but the memory power stays on when the breaker is off. I left everything on last sunday. Nothing with switched off. So being plugged in the starter was getting no charge and the on radio pulled to starter battery down to nothing.

@Tally Ho. check the wires from the back of your battery. If your radio keeps the presets when the breaker is off then there is likely a small wire (possibly yellow or red) that runs to an always hot lead somewhere. Mine is like that - has a breaker for power to operate the radio and a small hot lead connected, in my case, to a house battery "always hot" connection.

@BBC16385 With that said, those radio presets take very very little power and most likely would not drain your start battery over a week or even several weeks as long as your battery is in good condition and was fully charged when you left the boat even with no charging current going to the battery. Is there a breaker for your radio that shuts off 12V power to the radio itself. If not, was your radio left on when you went away. I would not expect the "preset power" load to be enough to drain your battery so I'd be looking for some other parasitic load.

Larger question is why the AC charger does not charge your start battery? On a boat of that size and vintage, I would fully expect the battery charger to either allow two charge outputs or a charge relay to be installed to charge the start and the house batteries from the AC charger. That may need to be corrected to make sure your start battery is always topped off.

 

[Davidasailor26]

The radio is a West Marine discontinued radio from five or more years ago. My connection is like yours in the diagram. But I have a cable coming off the battery terminals, no small wire. Where is the connection in your diagram? Behind the breaker panel?

Beneteau ran a wire off the main battery switch to a fuse, and from there to the bilge pump and radio yellow wire. The red wire is tied into a wiring harness that goes to a breaker on the DC panel.

 

[JoeWhite]

In cars the battery does not run down due to radio consumption. There are 2 wires powering the radio. One turns on the radio, the other should be permanently connected to the house battery to keep the clock running. It uses negligible power. It may also be required to keep the memory of preset alive. But it should not drain the battery within a week as mentioned above.
Movig these wires to the house bank is the correct wiring, specially since shore power keeps them charged throug the charger.

 

[Tally Ho]

Maybe my radio has a permanent connection to the battery as has been suggested (I don’t recall seeing one, but it certainly could be there and it makes sense to keep the presets and clock set), but last winter I worked on the most of the winter, so left the batteries connected (normally I would disconnect them to make sure there was no parasitic draw). I may get out to the boat once a month, to work on a project. No issues with my batteries. I would turn on the battery charger run off of an extension cord while I was at the boat to try to keep the batteries from running down. I was using the LED cabin lights while at the boat working.

So draining the battery from the parasitic load of the radio seems improbable. Something else is probably going on.

How old is the start battery? You said it doesn’t charge from the AC charger….how do you charge the start battery?

Greg

 

[smokey73]

If, as you say, the bilge pump is wired to the start battery I'd suspect it is cycling. Unless your bilge is always bone dry, it can cycle and you might not even know it. The bilge pump should be wired to the house battery, not the start battery and I'd suggest a bilge pump counter.

 

[BBC16385]

The starter battery is two years old. Lifeline AGM. It charges from the engine's 100 amp Balmar alternator and a Kohler generator. I would have no idea how to make any changes to change any of this. That is why I was hoping someone had dealt with this problem.

Maybe my radio has a permanent connection to the battery as has been suggested (I don’t recall seeing one, but it certainly could be there and it makes sense to keep the presets and clock set), but last winter I worked on the most of the winter, so left the batteries connected (normally I would disconnect them to make sure there was no parasitic draw). I may get out to the boat once a month, to work on a project. No issues with my batteries. I would turn on the battery charger run off of an extension cord while I was at the boat to try to keep the batteries from running down. I was using the LED cabin lights while at the boat working.

So draining the battery from the parasitic load of the radio seems improbable. Something else is probably going on.

How old is the start battery? You said it doesn’t charge from the AC charger….how do you charge the start battery?

Greg

 

[BBC16385]

In cars the battery does not run down due to radio consumption. There are 2 wires powering the radio. One turns on the radio, the other should be permanently connected to the house battery to keep the clock running. It uses negligible power. It may also be required to keep the memory of preset alive. But it should not drain the battery within a week as mentioned above.
Movig these wires to the house bank is the correct wiring, specially since shore power keeps them charged throug the charger.

I agree, but how?

 

[JoeWhite]

I agree, but how?

If you can remove the radio and follow the wires you will be able to trace them and see where they are connected. Use a piece of scotch tape and label them as to where they are connected now. Usually the red is positive that provides power. Turn the radio on and disconnect this wire. The radio should turn off. Reconnect and see if the presets are not lost. Then do the same on the yellow wire or any other color that is not black. This should erase the presets. Now you know which wires are needed. Connect red throug a fuse and switch to house battery and yellow preset wire to house bank directly.

 

[JamesG161]

On my H430 Stereo is connected to House Batteries.

Never worried about presets since I set them again in 5 minutes.

No way the "not playing" stereo drained your battery.
Jim...

 

[smokey73]

Agree with @JamesG161 There is no way the radio that is turned off drained your battery. There is something else going on. Do you know which battery bank your bilge pump is connected to? You can check this with brute force by:
1. Disconnect the negative wire on your house battery bank. Dump a 5 gal bucket of water in your bilge. If it does not start, the bilge pump is connected to the house battery. If it starts, the bilge pump is connected to you start battery.
2. To confirm what you just did in the previous step: Reconnect the neg lead on the house bank and disconnect the negative lead on your start battery. Dump another 5 gal bucket into the bilge and see if the pump starts. If it does not start, then your bilge pump is connected to the start battery. (it should not be connected to the start battery but maybe it is.) This is a brute force method and does not require any instruments. It either starts or it doesn't.

You are barking up the wrong tree if you think that a radio turned off with just the "preset" wire connected drained your start battery. If it did, then every one of us with a car and a radio would be having to jump start our cars when don't use it a week. The problem is somewhere else. My bet would be the bilge pump, If the bilge pump is connected to your start battery. I"d bet you either have a slow leak putting water in your bilge or a problem with your bilge pump that is causing it to cycle on every once in a while. That is why I recommend a "bilge counter" so that when you go to your boat you can quickly check to see if you have any water entering your bilge and/or if something else is causing your pump to cycle (like a faulty level switch.)

 

[artboas]

Is someone having dance parties in your cockpit when you’re not on board?

seriousky,,,
No way that quiescent standby current if a properly functioning radio drains your start battery.
And having said all if that, you want to install a Blue Seas ACR between your house & start battery. This will resolve your charging issues.