Aux/Radio Power vs. Main Switch

[Bob Buchanan]

My '96 Winn Adventurer has a dash switch that is labeled Radio Power with Aux underneath of those words. The other side of the switch is labeled Main. In '94 I had a Winn Brave with the same switch. Its obvious use is if I want to play the dash radio while parked -- and not running the engine. If I switch to Main while parked, the radio will not play. If I switch to Radio Power, the radio plays as I would expect it to. So I would assume the switch is allowing me to play the dash radio from the house batteries.

Have never played my dash radio that much in the past while parked - with the Brave or this rig. However, two things are different now. This rig has a gang busters dash radio. The other newbee is an iPod that I can connect to the dash radio. So here's the problem, and my question:

If the switch is set to Radio Power, the chassis battery is running down over time. For example, two nights ago, I forgot to turn the radio off and it played all night. The next AM, it began acting funny in that it kept going on and off by itself -- and would not play the iPod. I then checked the house batteries and they were full. Am hooked to shore power and have my 40A three state charger doing that chore OK. However, when checking the chassis battery, it registered around 7.7V. All of the rig batteries are new within the past 3 months.

If I connect my automotive charger to the chassis battery it comes alive and the dash radio comes to life again -- even tho the switch is still set to Radio Power vs. Main.

Question: What's going on here?? ????

 

[Jeff]

Bob:

On the Tradewinds Aux still uses chassis batteries for the radio but powers up the modulator to feed our TV sound to the system

 

[Bob Buchanan]

Bob:

On the Tradewinds Aux still uses chassis batteries for the radio but powers up the modulator to feed our TV sound to the system

Thanks, Jeff. I checked that in the owners manual -- and it specifically states that the Radio Power/Main switch allows running the radio off the house batteries and prevents running down the starting battery.

Other switches there on the dash allow me to kill the house batteries altogether, or another allows me to start the engine via the house batteries. The later I would imagine are on most coaches. Am surprised you would always have to run the dash radio via the chassis battery -- other that the Tradewinds must have a house radio that runs off the house batteries that one would normally use while parked vs. the dash radio.

 

[Jeff]

Thanks, Jeff. I checked that in the owners manual -- and it specifically states that the Radio Power/Main switch allows running the radio off the house batteries and prevents running down the starting battery.

Other switches there on the dash allow me to kill the house batteries altogether, or another allows me to start the engine via the house batteries. The later I would imagine are on most coaches. Am surprised you would always have to run the dash radio via the chassis battery -- other that the Tradewinds must have a house radio that runs off the house batteries that one would normally use while parked vs. the dash radio.

Bob:

One of the reason National is not concerned is that they installed an echo charger on the chassis batteries that feeds the same state of charge to the chassis batteries that the coach's are receiving. I replaced the chassis batteries that were six years old last month so it is a pretty good system, similar to having a battery minder on the chassis batteries which might help your situation.

 

[Karl]

Bob,

I think the switch is actually labelled Radio, and the two positions are Main and Aux. In the main position, you would probably have to turn the key to "On" or "Accessory" to operate the radio, but to have just the radio discharge the house batteries overnight doesn't make sense, unless it's also powering some other devices you don't know about. Are you sure someone didn't install a 1000 watt boom box while you weren't looking?

 

[Bob Buchanan]

Bob,

I think the switch is actually labelled Radio, and the two positions are Main and Aux. In the main position, you would probably have to turn the key to "On" or "Accessory" to operate the radio, but to have just the radio discharge the house batteries overnight doesn't make sense, unless it's also powering some other devices you don't know about. Are you sure someone didn't install a 1000 watt boom box while you weren't looking?

Yes, when I look again at the markings -- the words, Radio Power are above the word, Aux. And the word Aux is on the same level as the Word, Main.  Shhheeeezzzzzz, Robert!!!! However, the radio in the Aux position is not discharging the house batteries overnight, it's discharging the chassis battery overnight.

Actually, whoever owned this rig before me did add a boom box while I wasn't looking.    The sound cables are plugged into the back of the radio. But perhaps the the power to the boom box does not go through the same switching between Aux and Main that the Radio does?  ???

I wish I had been able to purchase this rig "before" coming to QZ. You, Jerry, Wally, Lou and many others would have made life a lot easier when trying to figure some of this stuff out that I hadn't run into before.

 

[Lou Schneider]

But perhaps the the power to the boom box does not go through the same switching between Aux and Main that the Radio does?? ?

I think you nailed it, Bob.? Most of the time a boom box is wired directly to the automotive fuse box, or if it's a really big one, it may have a seperate line going directly to the chassis battery for minimum voltage loss.

If the fuse size on the amp is less or the same as what's feeding the main radio, I'd try running it's power from the Main/Aux switch.? If you blow a fuse you can connect it to the house batteries.? If you do this, make sure the amp doesn't draw power while the radio is off - otherwise you'll put a phantom load on your house batteries.

 

[Bob Buchanan]

I think you nailed it, Bob.? Most of the time a boom box is wired directly to the automotive fuse box, or if it's a really big one, it may have a seperate line going directly to the chassis battery for minimum voltage loss.

If the fuse size on the amp is less or the same as what's feeding the main radio, I'd try running it's power from the Main/Aux switch.? If you blow a fuse you can connect it to the house batteries.? If you do this, make sure the amp doesn't draw power while the radio is off - otherwise you'll put a phantom load on your house batteries.

Thanks, Lou. I will see if I can trace those myself vs. going to an audio shop. It's really become a pain as I use the dash radio all the time now when parked. Must get it fixed as it continually runs down the chassis battery whenever it is on.

 

[lovelylittlerv]

Thanks, Lou. I will see if I can trace those myself vs. going to an audio shop. It's really become a pain as I use the dash radio all the time now when parked. Must get it fixed as it continually runs down the chassis battery whenever it is on.

I know this is from quite a while ago… but I’m having this same issue. What did you determine was the problem/fix?

 

[Lou Schneider]

Unfortunately, the last time Bob was here was back in 2014.

 

[Henry J Fate]

I am not sure there is a qualified fix for this switching setup. I have read different results from different coaches but it is a good idea to identify and confirm what your switch is doing so that you can manage the results accordingly.

On my 2001 Brave, it came stock with a similar switch to get the dash radio on without the key in the ignition. I believe the factory set it up to switch duty from the ignion switch to the house batteries which was the way I found it when I first bought the coach. It could have just as easily (maybe easier) been set up to bypass the ignition switch and connect the radio to the chassis battery. My dash radio has speakers in the living area so the use of the dash radio when camping is in the coach's design.

Later in the coach's life a backup/security monitor was installed. The installer used power from the radio circuit which provides power to the monitor in the same mannor as the radio.

What I eventually did was set up all the devices in the drivers compartment to work as the radio does. Those devices are CB, cigg plug, radio, monitor. The cigg plug and CB are always powered but the switch changes the power source between chassis and house. For my Brave, this modification was important because the chassis battery was not setup to charge when plugged into shore power or with the generator. In those circumstances, only the house batteries would receive charge current from the converter. Chassis battery charging was only set to charge from the chassis engine alternator.

Many ways the dash switch can be wired and designated at the factory. It is up to the builder to decide.