Audio Headunit - Always on 12V+

[pteck]

I just got done upgrading my audio headunit to new Pioneer bluetooth unit. With the infinitely more capable unit, maintaining my settings is that much more important. Really need a constant +12V supply to it.

Prior to this, I knew my old headunit would fully reset after using the store function on the trailer. Thought I would figure out something and find a constant on 12V supply when upgrading. Well, I'm now here, and there's no obvious 12V behind the cupboard.

For those that might have tackled this before, any creative solution or sources for that 12V supply?

I get that it will be a vampire draw when in store. But since I have solar, that's not much a concern. Much more concerning is that the headunit retains my audio, illumination, station and other settings! It's really not unlike a car. Airstream obviously was in the stone ages when my 2007 was built. I've searched the forums and no one seems either bothered by this, or tackled it.

I may just wind up splicing the always on 12V from the LP detector to run up to the headunit.

[Adventure.AS]

Why not just leave it in 'Use' mode all the time? You don't really need to isolate the batteries from the converter.

[J-Dog]

Is there room to place a small 12 volt battery nearby?

Not sure how long your trailer sits in storage. I would think 10amp hour battery could hold your radios memory for quite some time.

[pteck]

Leaving it in use is an interesting thought. I store my trailer next to the house, but don't leave her plugged in, so not really worried about the converter. Wonder if 200W solar would keep up with the larger set of phantom loads if I were to turn off the fridge and stereo manually?

In regards to DC backup batteries, there are such animals, but not many. I found a logic board from this company for ~$50. Add a small batt $10, and it certainly would work.
https://www.powerstream.com/DC-UPS-1212.htm

I'm more inclined to run a constant 12V back to the headunit. It would take a bit of work to snake it there, but I think doable. I poured over the electrical diagrams last night, and the LP Gas detecter is truly the only always on circuit. Though running from the batt distributions point is not that much harder for my specific trailer.

[OTRA15]

Originally Posted by pteck

. . .
I may just wind up splicing the always on 12V from the LP detector to run up to the headunit.

Is the wire to the propane detector a large enough AWG, and is there an inline fuse for that, similar to the inline fuse for the tongue jack?

I would consider biting the bullet and running a new dedicated wire from the batteries to the new audio unit with its own inline fuse. Maybe under the chassis and up somewhere under the audio? Or an interior path if possible. Not sure about your floor plan.

Good luck!

Peter

[Mattirs]

Originally Posted by pteck

Leaving it in use is an interesting thought. I store my trailer next to the house, but don't leave her plugged in, so not really worried about the converter. Wonder if 200W solar would keep up with the larger set of phantom loads if I were to turn off the fridge and stereo manually?

200W solar is more than sufficent. A small 40W unit would work in that it would take up less space deployed.

Matti

[pteck]

Good point.

The headunit has a 10amp fuse, so that would be the max when on.

Automotive headunits have 2 +12V wire inputs. The larger gauge one (typically yellow) is indeed the one responsible for memory, but also supplying most of the current when on. The red wire is the switched ignition, that likely doesn't do much other than powering a relay.

I am definitely leaning to running a dedicated wire from the 12V junction source onboard, since it's not very hard to run there. And yes, an inline fuse is always important for any run like this.

Another weekends project as I'm definitely not going to bother myself with a reset headunit every time: cancelling demo, setting the illumination colors, speaker setup, clock, subwoofer gain, and loudness. The only thing it seems to keep is the paired BT source.

[m.hony]

...or run a wire from the head unit directly to the battery for a constant 12 volt power supply to keep all the settings in the head unit...

[greghoro]

Disclaimer, this is based on wiring diagram for 2012 Flying Clouds.

Internal trailer circuits that typically always have 12V regardless of the "Use" mode switch:
- The "Use" mode relay
- The "Use" mode switch itself (gotta have power to turn the relay back on)
- The Propane detector in the kitchen
- Surge brake breakaway switch
- Charge line from 7 way connector

You can throw in the tongue jack, but that does not have any internal wiring.

I my opinion and for full disclosure to future owners, I would run the fused wire to the hot side of the "Use" mode relay and attach some masking tape with a notation of what the wire is for. Fuse should be as close to the 12V source as possible.

Since this is going to be the sole source of 12V for the radio, you will need to document this somehow for future owners, who would go crazy trying to figure out why the radio is not getting power if the fuse blows.


Greg

[greghoro]

Another thought, just brainstorming now.

At the 12V fuse panel, find the circuit wire powering the radio. Disconnect the fuse and find out what else the circuit powers. There may also be a label on the converter indicating what the fuse powers.

If you are OK with always powering that circuit, remove the wire from the fuse panel and run a wire from it to your always powered source, properly fused for the total load. Much less problems fishing this wire.

Again, any such modification may stump someone trying to rectify a blown fuse, so you will want to make a note on the converter door.


Greg

[Byronshugart]

Can you upload your receivers settings to a memory stick?
Some units are able to do this.

[Al and Missy]

MOst of the head units I have installed in cars or my trailers have two 12V lines, a switched and an unswitched. Typically the unswitched 12V line draws very little current.

Al

[alano]

As long as you're looking for creative solutions, you might consider doing this...



This would allow you to run a wire from your propane connection to provide power for the backup memory, yet allow the switched +12 V to provide power for the amplifier.

[wulfraat]

Heya. The place to draw constant 12v from is the hot bus bar which is located where the batt cables enter the trailer. This is where the brakes and propane detector are connected to constant 12v positive, upstream from the battery disconnect switch, which btw is typically located right next to the positive bus bar. It’s from the bus bar that there is a 4ga wire over to the main switch for ‘batt disconnect’ that feeds the rest of the trailer, including the 12v fuse panel.

The main bus bar is usually located in the very front of the trailer. In my case (both in my 25SS and 30’ rear bed) this is under the couch with the radio mounted in the upper bin - so it’s not to bad to fish a wire up which is concealed via the panoramic window trim.

Everything else 12v - wise in the trailer is downstream from the batt disconnect switch so you won’t get constant hot unless you tap the propane detector wire, which is likely more trouble than it’s worth as fishing wires is the main challenge in delivering constant 12v to the radio.

[pteck]

Originally Posted by Adventure.AS

Why not just leave it in 'Use' mode all the time? You don't really need to isolate the batteries from the converter.

I haven't bothered running an always +12V line yet.

But I have been leaving my trailer on in the "Use" position. And it's working out just fine.

Solar is such a game changer in regards to parasitic draw. At least for someone that stores their AS out in the open.

[Mollysdad]

Originally Posted by Adventure.AS

Why not just leave it in 'Use' mode all the time? You don't really need to isolate the batteries from the converter.

Here's my latest plan. "Use" mode will boil off the batteries if you leave it plugged in. "Store" will save the batteries, but the parasitic draws will eventually drain the batteries.
I'm leaving mine in "store", but placing a NoCo Genius 3.5 amp charger on the batteries, run to the 120v. AC.
Eventually, I'll put a battery disconnect on the battery box (which seems to have plenty of room to route cables.)

[pteck]

Great, but that doesn't answer the issue at hand here which is the head unit standby power.

With a 3.5amp charger, it might just be sufficient to leave the trailer in use, keeping the headunit powered with other parasitic loads, and batts topped off.