Community Forums

wjell · 07-12-2013, 10:51 AM

I have the above coach that has been "modified" by POs. My problem is that when 120V is not present the 12V does not come on. I know the coach battery is worn out. It reads 3.5V (probably not even getting charged from the converter?) but I think it still should lite a LED. It there some manual switch somewhere I don't know about?

It has a Parallax Power Components 3240 Converter in the hallway and a Todd Engineering Electric Generator - Shoreline Transfer Switch in the water hold area. The Generator is non-functional. I just want to make sure my 12V works.

RedWing Nut · 07-12-2013, 11:09 AM

Have you tried hooking a battery charger to the coach batteries?

wjell · 07-12-2013, 11:15 AM

Yes, I tried charging one of them. I think I got it up to about 7V. I know these batteries will need to be replaced. I just am wondering why I am not switching to 12V when the 110V is removed.

RedWing Nut · 07-12-2013, 11:21 AM

I was wondering if the lights and other 12V items work with the battery charger hooked up to the cable-ends at the battery and the power cord unplugged.

wjell · 07-12-2013, 02:14 PM

My problem is that if I unplug the 110V I won't be able to power the battery charger which uses 110V.

Capn_Dave · 07-12-2013, 03:42 PM

You already have answered you question. You need the battery charger to be on to get 12 volts.

Test it out for yourself take your car battery and place it where your house batteries are, make sure it is charged up and go turn your lights on.

wjell · 07-12-2013, 04:17 PM

Partially correct. I just remembered that I have one of those little portable battery units that will jump start a car and also has a 110V outlet on it. These were one of greatest inventions of the last 50 years. That is probably why they don't make them anymore. I'll use the units jumper cables to attach it to the remaining battery tomorrow and disco the 110V. But I have a feeling that something required to make the switch between 110V to 12V has been FUBAR'd by human hands.

Rich and Cork · 07-12-2013, 05:25 PM

...and you don't just go and get a new battery because????

wjell · 07-12-2013, 06:38 PM

Quote:

Originally Posted by Rich and Cork

...and you don't just go and get a new battery because????

BECAUSE... I'm not sure that this is a BATTERY PROBLEM. Following that logic would be like replacing a flat tire on a vehicle with a broken axle.

I will attach the booster battery and see if is "solves" the problem in the troubleshooting matrix, but I doubt it.

My original question was if there was some manual "switch" that needed to be activated to facilitate the switchover in a RV of this era/make with the detailed equipment.

ahicks · 07-12-2013, 06:39 PM

I don't understand maybe. If you unplug the coach from 110 power, and your batteries are dead/junk, where are you expecting the 12v power to come from?

Ok, I was typing while you were. You're trying to figure out if you batteries are being charged when the coach is plugged in to 110?

If so, disconnect the batteries, or at least maybe just one side. Then measure the voltage going to them with the coach plugged in. It should show something in the neighborhood of 13.5-14 volts. If not, you'll need to do further trouble shooting to see if you have a charge circuit (and I would suspect you do) and what's going on with it.

PlayItForwrd · 07-12-2013, 06:43 PM

Our last motorhome, an '87 CruiseAir III, had enough soleniod relays under the hood to work the space shuttle. Those relays switched everything (no manual switches). However, they would need way more than 7 volts to even activate the magnet.

My best guess is you also have a few solenoids in your 12 volt loop and without 12 volts, they won't work--

And regardless of whether or not the batteries are causing the problem, you're going to have to buy new batteries anyway, so it won't be wasted money. And new batteries may help diagnose - or eliminate the problem.

>edit< -- I just remembered after typing about the solenoids that I'd messed with them last summer, and found each solenoid had TWO fuses, one for the incoming hot, one for the outgoing hot. They're the common 'square' fuses, and there was a special spot for them. Found them by accident. Also found a couple of the fuses were blown...

wjell · 07-12-2013, 07:09 PM

Ahhhh... Ahicks and PlayitForwrd. Excellent points.

Ahicks, good point. I will disco the batteries and see if there is recharge current coming from the converter. My guess is not. I kinda feared that, but still immediately more worried more about the lack of "switchover" from 110V to 12V. I can put a trickle charger on the house batteries if I need to until I figure that one out.

PlayItForwrd, good point. I will hook up the "booster" battery unit and see if that solves the problem. Maybe there is not enough punch in the punch?

Please, for both of you (and anyone else) how do you trace wires through a 35' motor home? In my past computer/network/telco experience I worked with what is called a "tone generator". It puts an electronically audible "tone" on a wire in order to identify it. Good ones are expensive but there are some less expensive models out there.

How else can you trace wires?

wjell · 07-12-2013, 07:13 PM

Quote:

Originally Posted by PlayItForwrd

I just remembered after typing about the solenoids that I'd messed with them last summer, and found each solenoid had TWO fuses, one for the incoming hot, one for the outgoing hot. They're the common 'square' fuses, and there was a special spot for them. Found them by accident. Also found a couple of the fuses were blown...

Were they by/imbedded in the solenoid or somewhere else?

Capn_Dave · 07-13-2013, 04:59 AM

The 12 volts is there all the time. You are not switching anything. When you are plugged in the battery charger is on and feeding 12 volts to the batteries, charging them and powering the lights, at the same time. When you disconnect the 110 volts AC, the batteries are the only power supply for the 12 volt system. No switch.
Do you have a vom? If so check the voltage on the batteries with and without the 110 hooked up.
I really think you arte trying to overthink the problem.