Constant Power to Stereo

[Alita49DS]

As my, better, teachers used to say, read the question before answering an examination paper.

The question was rather a good one. And did not include convoluted ideas such as solar power.

"Is it possible to connect the stereo's constant power to a dedicated battery?"

It also asked about leads.

Taking the question:

1. there is a convention for car/marine radios/stereos. The red wire is the switched feed to run the unit. The yellow wire is the always on positive feed to retain memory.
2. There is also a negative feed which must be always earthed
3. The manufacturers, who can be assumed to know better than certainly I do, have this arrangement precisely to avoid the unit flattening the battery
4. It is a very bad idea indeed to leave the circuit breaker to the red positive feed on. With modern sets there can always be standby and other settings which might not be apparent. Think of your home TV and why it can be sensible to pull the wall plug.
5. The question is therefore spot on: how do you retain current to the yellow memory lead which is kept separate for good reason?
6. The questioner excludes wiring back to a constant live feed. That would be the best and cheapest option and an inline 1amp fuse would be all that was needed. However, he excludes it.
7. As others have written, the draw of the yellow lead is absolutely tiny.
8. It follows that there is no reason that I can see why something like a small motorcycle/moped battery would not do. But there are the problems of running to negative to it and also recharging it.
9. One simple option that occurs to me, and I would be interested if others were to comment, would be to use a mobile phone battery bank with the yellow lead connected to the positive feed of such as a USB-C plug. Although that feed would be only 5v, USB-C can probably provide more than enough amps to keep the memory of the stereo alive. Further, when the stereo is in use the battery bank is easy to charge.

Just an idea. I would be interested to know, from a better electrician than I am, why that would not work.

FYI, I had the issue on my boat and running a constant feed to the yellow + was far less aggravation than setting up the radio each time that I was on the boat. The draw does not even tickle the AMP meter on the boat so in my view can be simply ignored.

[NorthCoastJoe]

You can get a $10 solar panel with a male lighter plug at Harbor Freight that will more than cover the stereo vampire drain. Cut off the lighter plug and wire directly to your battery. Simple and cheap.

[Alita49DS]

Originally Posted by NorthCoastJoe

You can get a $10 solar panel with a male lighter plug at Harbor Freight that will more than cover the stereo vampire drain. Cut off the lighter plug and wire directly to your battery. Simple and cheap.

1. Is that going to provide constant power? I doubt it.
2. If it is going to be on deck you need to run the wire and get a deck gland.

Therefore, why not just do the job properly and run a wire to the constant feed? Or, failing that, use a battery pack? As the question asked.

[a64pilot]

I wouldn’t want to fuse my bilge pump. I have a CB on the panel that you can see if it’s popped.

Auto’s can have significant “dark current” there are three computers, engine, body and transmission control modules, as well as usually an alarm system, radio memory is a tiny fraction of what there is.

[Alita49DS]

Originally Posted by a64pilot

I wouldn’t want to fuse my bilge pump. I have a CB on the panel that you can see if it’s popped.

Auto’s can have significant “dark current” there are three computers, engine, body and transmission control modules, as well as usually an alarm system, radio memory is a tiny fraction of what there is.

I also have a circuit breaker (CB) for the bilge pump.

That said, and for the benefit of my education, is there actually any functional difference between a CB and a fuse? Other than that a CB is easier to spot if it pings and far easier to reset.

Having just rewired a ceramic bodied fuse in my house, a pig of a job getting the fuse wire around the screws, I think that CBs are the best thing since sliced bread!

[capt jgw]

Originally Posted by a64pilot

I wouldn’t want to fuse my bilge pump. I have a CB on the panel that you can see if it’s popped.

Auto’s can have significant “dark current” there are three computers, engine, body and transmission control modules, as well as usually an alarm system, radio memory is a tiny fraction of what there is.

And the newer cars typically have tiny batteries. If you can leave them for weeks and they still start, it demonstrates that the parasitic loads really don't matter.
The DC panel in my boat has an unswitched bus that feeds the breakers and loads I don't want switched like the bilge pumps. I connected the yellow wire to that bus and the red wire to a breaker marked "Stereo". The memory stays alive and the stereo only runs when it's breaker is on.
An older boat wired for an old fashioned stereo (remember the ones with knobs?) might not have a spot for the yellow wire, those radios didn't have one. In that case connect the yellow wire to the input side of the master breaker or wherever the positive feed from the battery is connected. That feed would be unswitched in the panel, but might go through the 1-2-All switch depending on how the boat is wired. And of course include a 1 amp fuse.

[NorthCoastJoe]

I was not saying to hook it up to the stereo directly. Common sense, use it to keep the battery topped off. Do not make it complicated. These panels are made to lay on a dashboard in a car and plug into a lighter plug to keep batteries topped off.

You can run the wire through any opening like the crack around the companionway opening when the boards are in. It is 6"x12" plastic panel not a big deal put it inside when your sailing and toss it out in the cockpit to keep the batteries topped off when you leave.

[Reefmagnet]

Originally Posted by Alita49DS

I also have a circuit breaker (CB) for the bilge pump.

That said, and for the benefit of my education, is there actually any functional difference between a CB and a fuse? Other than that a CB is easier to spot if it pings and far easier to reset.

Having just rewired a ceramic bodied fuse in my house, a pig of a job getting the fuse wire around the screws, I think that CBs are the best thing since sliced bread!

Circuit breakers are more prone to nuisance tripping from sustained loads than a standard fuse as their ratings are approached. And for motors starting under load or otherwise prone to surging loads, there's also the option of switching to "slow blow" fuses. Breakers can also become progressively more sensitive to nuisance tripping the more times they trip in regular service. It's also possible to buy fuses and/or fuse holders that have a visual indicator that shows if they've blown. Not that that will make any difference on an unattended vessel which is when a reliable supply of power to the automatic bilge pumps is far more critical.

I use both breakers and fuses on my boat, including a "self resetting circuit breaker" for the "always on" supply which the automatic bilge pumps and radio yellow wire connect to (all independently fused, of course), but I trust fuses more and like the idea I can switch fuses out quickly and change the type or rating as required.

[a64pilot]

Properly sized a CB should never trip unless there is a fault.
If you ever have nuisance trips, then something’s wrong, there is a fault.
Every aircraft I’ve ever flown was full of circuit breakers, usually dozens, with only one instance of nuisance tripping, that was when the 30MM cannon was fired on the early A model AH-64. That was from vibration and was fixed with an O-ring.

Think about it, most all of us have breaker panels, how often do breakers trip without there being a problem.
Anyone who responds positively has a problem that needs addressing

All CB’s are slow blow in that it’s a time and amperage that makes one trip. They will usually sustain current well over rating for short times.
Follow this link at the bottom is a graph for the common 15 amp CB, see that for short times it will hold about 400% of rated capacity etc. it takes a full second at rated capacity to trip.
https://www.bluesea.com/products/740...ingle_Pole_15A

[Reefmagnet]

Originally Posted by a64pilot

Properly sized a CB should never trip unless there is a fault.
If you ever have nuisance trips, then something’s wrong, there is a fault.
Every aircraft I’ve ever flown was full of circuit breakers, usually dozens, with only one instance of nuisance tripping, that was when the 30MM cannon was fired on the early A model AH-64. That was from vibration and was fixed with an O-ring.

Think about it, most all of us have breaker panels, how often do breakers trip without there being a problem.
Anyone who responds positively has a problem that needs addressing

All CB’s are slow blow in that it’s a time and amperage that makes one trip. They will usually sustain current well over rating for short times.
Follow this link at the bottom is a graph for the common 15 amp CB, see that for short times it will hold about 400% of rated capacity etc. it takes a full second at rated capacity to trip.
https://www.bluesea.com/products/740...ingle_Pole_15A

....Versus these times for fuses

[Howler]

Originally Posted by Alita49DS

As my, better, teachers used to say, read the question before answering an examination paper.

"Is it possible to connect the stereo's constant power to a dedicated battery?”

1. there is a convention for car/marine radios/stereos. The red wire is the switched feed to run the unit. The yellow wire is the always on positive feed to retain memory.
2. There is also a negative feed which must be always earthed
3. The manufacturers, who can be assumed to know better than certainly I do, have this arrangement precisely to avoid the unit flattening the battery
4. It is a very bad idea indeed to leave the circuit breaker to the red positive feed on. With modern sets there can always be standby and other settings which might not be apparent. Think of your home TV and why it can be sensible to pull the wall plug.
5. The question is therefore spot on: how do you retain current to the yellow memory lead which is kept separate for good reason?
6. The questioner excludes wiring back to a constant live feed. That would be the best and cheapest option and an inline 1amp fuse would be all that was needed. However, he excludes it.
7. As others have written, the draw of the yellow lead is absolutely tiny.
8. It follows that there is no reason that I can see why something like a small motorcycle/moped battery would not do. But there are the problems of running to negative to it and also recharging it.
9. One simple option that occurs to me, and I would be interested if others were to comment, would be to use a mobile phone battery bank with the yellow lead connected to the positive feed of such as a USB-C plug. Although that feed would be only 5v, USB-C can probably provide more than enough amps to keep the memory of the stereo alive. Further, when the stereo is in use the battery bank is easy to charge.

FYI, I had the issue on my boat and running a constant feed to the yellow + was far less aggravation than setting up the radio each time that I was on the boat. The draw does not even tickle the AMP meter on the boat so in my view can be simply ignored.

Hi Alita49DS,

Thanks for addressing my original posting in so much detail, including preference to avoid fishing wire, or rigging solar panels!

Some questions / comments to your points above:

1. There’s effectively a yellow lead for “always on”.
2. There’s a ground wire as part of the bundle of wires going through the DIN connector. I’ll have to trace it to be sure, but is it typical that boat manufacturers prewire that permanently to earth, or would the earth connection only work when the circuit breaker for the stereo is on?
4. Agreed. This radio (Pioneer MVH-X580DAB) has a lot going on in so-called standby mode!
5. Actually the yellow wire is part of the bundle going through the DIN connector. I assume the boat manufacturer didn’t connect it to anything at the other end. It would have to be separated from the rest in order to rig to a continuous power supply, regardless if it’s to the main battery bank or a separate power supply.
8. This is what I was initially wondering, only instead of a motorcycle battery, I was thinking of one of those 12V rechargeable li-ion battery backs ($20-35 on amazon). Apparently you can recharge them while using them to power a device. The problem, as you mention, is what what to wire to the negative terminal of an independent battery solution.
9. How would this solution alleviate the need to run a negative wire back? I’m not good with electricity (ask me anything you want about marine plumbing), but I do know that a DC battery circuit needs to be a closed loop.

This radio has so many settings, it takes a checklist and 10 minutes to reprogram it. For now, I leave the circuit on day to day when cruising, but when the boat’s left at the dock, I turn everything on the panel off, especially because the all the boat’s USB outlets and fans are wired to the same circuit as the stereo.

Again, thanks for all the interesting ideas!

[Howler]

Originally Posted by capt jgw

And the newer cars typically have tiny batteries. If you can leave them for weeks and they still start, it demonstrates that the parasitic loads really don't matter.
The DC panel in my boat has an unswitched bus that feeds the breakers and loads I don't want switched like the bilge pumps. I connected the yellow wire to that bus and the red wire to a breaker marked "Stereo". The memory stays alive and the stereo only runs when it's breaker is on.
An older boat wired for an old fashioned stereo (remember the ones with knobs?) might not have a spot for the yellow wire, those radios didn't have one. In that case connect the yellow wire to the input side of the master breaker or wherever the positive feed from the battery is connected. That feed would be unswitched in the panel, but might go through the 1-2-All switch depending on how the boat is wired. And of course include a 1 amp fuse.

Good idea. This would avoid fishing wired all the way to the battery. I’m still concerned about the draw being greater than just keeping station memory live. This stereo has Bluetooth, DAB, and numerous other things going on. On the other hand, when at dock, I have shore power topping off the battery so I guess that wouldn’t matter.

[Tillsbury]

I have a circuit breaker on my panel labelled bilge pump. The bilge pump is, of course, wired directly to the bank with its own fuse, so it can’t be switched off accidentally.

I use the circuit breaker as a “24/7” supply. It powers a backup bilge pump, and anything else I want on all the time: the router and wifi amplifier, the battery monitor, various alarms, and the permanent power to the stereo.

If you think of one circuit as being a “normally on”, then you can wire things appropriately.

When I leave the boat, i switch off every circuit except the 24hr one and the fridge.

[Lake-Effect]

Originally Posted by Howler

Hi Alita49DS,

4. Agreed. This radio (Pioneer MVH-X580DAB) has a lot going on in so-called standby mode!

I'm betting that most boat stereos will draw just the memory holdup current through that yellow lead, when their own power switch is off.But you don't have to guess; you can measure the actual currents on the red and yellow leads.

[Spot]

Hey Howler,
I am using a low-powered solar panel to keep the battery up on my sailboat.
Simple parallel installation (+ to +, - to -, no additional wires or controllers).

I looked at the Pioneer manual for your unit. It would have taken me a couple tries to get it right.

https://catalogs.pioneer-car.eu/Manu...anual/?page=20

On my boat with no alternator/generator I am probably going to skip 'big' audio and use a Bluetooth speaker tied to a tablet or phone.

Ah, electricity and plumbing...both are glorious when working and a pain when not.