Sound system

[Steel sails]

Any recommendations. I have a Sony installed but it's a automotive model designed to always have power even in the ignition off mode. Every time I turn the master breaker off it looses its programing.
It's 12v and the dc system is 24v so it's not ideal to bypass the breakers and connect it to the batteries directly.
I use a dc to dc converter to run my 12 v
I am looking for something that retains its memory when power is disconnected
Thanks
Paul

[colemj]

Pretty much all automotive audio systems have a "keep power" wire - I don't know one that does not. This wire is connected around the power switch and keeps the memory alive when the power is turned off at the breaker. The parasitic draw is very small - a few milliamps.

I bet your current one has this wire and it is not hooked up. Check your installation manual and the wiring to the unit. Maybe the wire is also connected to your breaker. If so, remove it and connect it straight to uninterrupted power.

And post a picture of your boat in the "what cat looks best" thread.

Mark

[Steel sails]

Because the boats 24 v I have to run that always on wire thru the dc to dc converter. The vhf, AIS and a few other things run from this so when I turn that off via the breaker i loose the always on power.
I was thinking about putting a small lithium 12 v in the radio line but then have to think about charging it.
Was hoping to find something with a watch type battery in it to keep the settings.
I'll try to post a photo today
Thanks
Paul

[colemj]

While your choices are more limited, 24V car stereos are made. Blaupunkt and others make them. Alternatively, you could dedicate an inexpensive 24-12V converter to the keep alive wire and never turn it off.

Mark

[rwidman]

Originally Posted by Steel sails

I was thinking about putting a small lithium 12 v in the radio line but then have to think about charging it.

Connect one up and see how long it lasts. Not a rechargable, just a normal battery. If it lasts six months or more, that's your solution.

I'm assuming your 24 volts comes from two 12 volt batteries so you could just connect the memory wire to the first in the series. That's 12 volts and not enough current to worry about.

[Lake-Effect]

Originally Posted by rwidman

Connect [a small 12 battery] up [to the memory wire] and see how long it lasts. Not a rechargable, just a normal battery. If it lasts six months or more, that's your solution.

I'm assuming your 24 volts comes from two 12 volt batteries so you could just connect the memory wire to the first in the series. That's 12 volts and not enough current to worry about.

I agree with these ideas; the current drawn by the memory wire shouldn't have serious effect on the system. Fuse the memory wire close to the battery.

I've never worked on a boat with a 24v system. Is this just for the starter, or are most of the other loads (eg lighting) also 24 v? Given the amount of important boat stuff that runs on 12v, I'd be tempted to add a group 24 12 battery to the boat that's at least a standby source for all your 12v stuff. There are a number of ways to safely charge a 12v battery from a 24v source. This could be a godsend if the 24v to 12v regulator ever fails.

[noelex 77]

Just add a small sealed 12v lead acid battery.

The 24/12v converter will keep it charged, not with the ideal charging algorithm, but it will last several years and theyare cheap to replace.

Make sure only the memory wire is attached.

[David M]

Just put the power and the memory wires across one of the batteries. That will get you 12 volts. You will want to put inline fuses at the power source for both the power wire and the memory wire.

Or run the power wire to a breaker on the load side and the memory wire to the source side....thats if you have your electrical system set up with 12 volts to a spare unused breaker. Many 24 volt DC systems have a 12 volt side for 12 volt DC loads.

[smac999]

There are radios that retain settings when off. (Probably built in battery). But off hand I can't name models. Maybe the fusion but I'm not sure

Or as above 24v radio would solve it but I imagine would have limited options.

there isn't really a good way otherwise. Other the leaving the converter always on and switching only the outputs (except the stereo memory). But then you have a decent size draw all the time running the converter.

Another option might be a smal. ~10a 24-12v converter and connect direct from batter to mem wire. Might have less standby draw then your large 24-12v converter.

If you are going to put in a battery I would put in a 12v bank and move all 12v to it , remove converter, ad get a 24-12v charger.

[smac999]

Originally Posted by David M

Just put the power and the memory wires across one of the batteries. That will get you 12 volts. You will want to put inline fuses at the power source for both the power wire and the memory wire.

Or run the power wire to a breaker on the load side and the memory wire to the source side....thats if you have your electrical system set up with 12 volts to a spare unused breaker. Many 24 volt DC systems have a 12 volt side for 12 volt DC loads.

No, don't center tap batteries.

His 12v side gets shut off when he turns his 24v off. He has no 12v constant source to connect too

[smac999]

Originally Posted by rwidman

Connect one up and see how long it lasts. Not a rechargable, just a normal battery. If it lasts six months or more, that's your solution.

I'm assuming your 24 volts comes from two 12 volt batteries so you could just connect the memory wire to the first in the series. That's 12 volts and not enough current to worry about.

It wouldn't 't last long. Must radios draw power from the constant line so it's 2-3amps with radio on. And the Acc wire is just the wake up line