New rv owner with 12 volt problems

Ive just purchased a 1992 georgie boy encounter that had been sitting for 8 years. Ive finally got the shore power and generator systems working but.. theres always a but..the 12 volt systems all work on shore power and generator but are all dead when the 110 is off. This tells me that the converter from 110 to 12 dc is working and powering the systems  but the house batteries (2 brand new deep cycle wired paralle) seem to be losing  charge.
Checked all fuses that i can find.  Open to suggestions on where to look,  isolater switch? need new converter? Etc
Thnx for the help, we are going on our first shakedown cruise this weekend but dont want to run the generator continuosly

With the new house batteries wired in parallel, I'm assuming they are both 12 volt? If they are 6 volt, they need to be wired in series. Assuming they are wired correctly, I would start tracing wiring and researching switches to see if there is a battery disconnect. The battery disconnect could be one where actual battery voltage passes through it, or it may operate a solenoid. Also check to see if all the wiring from the coach is connected to the batteries. I would think the converter is good since it powers the 12 system when you have 120 volts A/C available.

That symptom is also indicative of a battery disconnect switch (aka Salesman switch) being off. In many coaches, 12 volt systems will work when on generator or shore-power if the disconnect switch is off, but when disconnected from A/C power, 12 volt systems won't work. That's how all three of our motorhomes worked anyway.

Look for a disconnect switch near the door (they're sometimes located elsewhere) and make sure it's in the correct position. Flip the switch a couple of times and listen for a "clunk" sound. That's a solenoid that actually connects and disconnects the power. If you don't hear it, that solenoid might be stuck, which wouldn't surprise me after eight years of sitting.

Kev

Kevin Means said:

That symptom is also indicative of a battery disconnect switch (aka Salesman switch) being off. In many coaches, 12 volt systems will work when on generator or shore-power if the disconnect switch is off, but when disconnected from A/C power, 12 volt systems won't work. That's how all three of our motorhomes worked anyway.

Look for a disconnect switch near the door (they're sometimes located elsewhere) and make sure it's in the correct position. Flip the switch a couple of times and listen for a "clunk" sound. That's a solenoid that actually connects and disconnects the power. If you don't hear it, that solenoid might be stuck, which wouldn't surprise me after eight years of sitting.

Kev

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evin
In my coach if/when the "salesman switch", (aka: the "domestic 12V power switch"), is OFF, or (if it sticks in the OFF position), the 12 volt system in the coach will NOT work all... (even when connected to shore power... or when the generator is running).

Mines like Kev's. All 12 volt will work on 110 plug in or gen with chassis battery disconnect off, but house batteries won't charge.

mel s said:

evin
In my coach if/when the "salesman switch", (aka: the "domestic 12V power switch"), is OFF, or (if it sticks in the OFF position), the 12 volt system in the coach will NOT work all... (even when connected to shore power... or when the generator is running).

Click to expand...

Funny you'd mention that. Until recently, I thought all disconnect switches were wired like all three of ours have been (and my bother-in-law's two motorhomes.) Then, the other day, someone said theirs was wired like yours. Just curious, what year/make/model of coach do you have?

Kev

Multiple possible issues. .But first a question:

What make and model converter does that beast have?  There was once one, and I assume more, that was a two part device, a 12 volt "power supply" that delivered rectifed AC to things like Lights and such that don't mind that kind of party. and a 2nd one that charged the battery and also ran things like Radios.

On these models, there was a relay that could need attention.

You may have your DISCONNCT switch set to OFF (Batteries disc onnected)

There shoudl be a fuse, or circuit breaker, Mine is self=resetting but yours might not be.

Then there are real problems.

Royeyford said:

Ive just purchased a 1992 georgie boy encounter that had been sitting for 8 years. Ive finally got the shore power and generator systems working but.. theres always a but..the 12 volt systems all work on shore power and generator but are all dead when the 110 is off. This tells me that the converter from 110 to 12 dc is working and powering the systems  but the house batteries (2 brand new deep cycle wired paralle) seem to be losing  charge.
Checked all fuses that i can find.  Open to suggestions on where to look,  isolater switch? need new converter? Etc
Thnx for the help, we are going on our first shakedown cruise this weekend but dont want to run the generator continuosly

Click to expand...

If you don't have a volt meter to start trouble shooting, you really need one.  You can buy one at Walmart for under $20.

You say the house batteries seem to be loosing charge.  How did you determine they are loosing charge? Did you measure the voltage to determine the state of charge.  How long between full charge and "loosing charge"?

Ok time for an update. The "salesmans switch"  doesnt make any difference which position it is in. Still no electricity to any 12 volt systems unless plugged into shore power or the generator is running.
There is a clunking noise under the motor home when i move the switch from one position to the other, i havnt traced the clunking noise because i need someone to flip the switch while i look, but going by the noise, theres a solinoid switching somewhere.
Under the hood is schematic in photo. There is 12 volt power to all 4 terminals of the "aux. battery disconnect iso" switch, the "battery iso (optional)"  and the "battery iso"  (top left in photo)

Won't let me post photo of schematic

trying to upload schematic for previous post

trying to load schematic

You can take a voltage reading across the solenoid to see if it's passing power through. Just because it clunks doesn't make it good. That just means the coil in the solenoid is good. You can also jump the two large terminals with a jumper cable. If that gives you power, the contacts in the solenoid are bad. I can't make out anything on the drawing on my cell phone. Sorry.

It's hard to follow the drawing you posted (not what I'd call a schematic  : ).  Is there another panel inside with the house fuses or are they all under the hood?

If there's another panel somewhere, I'd suspect the 50 amp breaker marked "Converter" in the schematic.  I'm thinking the converter is directly connected to the house fuse panel somewhere outside the scope of this drawing and the 50 amp breaker is supposed to protect the battery charging line coming from the converter.

If it's open, it would also stop the battery voltage from getting back to the converter and house fuse panel.

Success!!!
thanks to all the helpfull advice.
I traced the wire backwards from the converter in the back, (under the rear bed) to the fuse panel under the hood (where i had found the schematics pasted inside the fuse panel lid)
The converter 50 amp fuse is dead. I shorted across the terminals and voila, the interior 12 volt lights are working without being on shore power so its off to town this morning to get another 50 amp fuse.
The converter is only showing 11.9 volts output  when on 110 volt but the batteries up front are showing 13.9 volts at the posts so the converter might need replacing,
Is it normal for the converter to be making a loud humming noise?
Are converters a generic item, as in, if its a 50 amp converter,  can i just replace it with another 50 amp?
Again, thanks so much for all the advice, its a steep learning curve for this old cowboy.

Royeyford said:

Success!!!
thanks to all the helpfull advice.
I traced the wire backwards from the converter in the back, (under the rear bed) to the fuse panel under the hood (where i had found the schematics pasted inside the fuse panel lid)
The converter 50 amp fuse is dead. I shorted across the terminals and voila, the interior 12 volt lights are working without being on shore power so its off to town this morning to get another 50 amp fuse.
The converter is only showing 11.9 volts output  when on 110 volt but the batteries up front are showing 13.9 volts at the posts so the converter might need replacing,
Is it normal for the converter to be making a loud humming noise?
Are converters a generic item, as in, if its a 50 amp converter,  can i just replace it with another 50 amp?
Again, thanks so much for all the advice, its a steep learning curve for this old cowboy.

Click to expand...

Some converters do make a humming noise.

When you say "the batteries up front are showing 13.9V" are those batteries the house batteries or chassis batteries? 

When the 110 volt power is off are you seeing 11.9V at the converter?  I am guessing you are see 0V since the 50amp fuse is bad. 

What voltage at the converter do you see when you jumper across the 50 amp converter fuse AND you are on 110V power. 

I agree, seeing 11.9V at the converter is not correct, when on shore power.  However I supposed the converter could only put out the low voltage when it is not connected to a battery.  I would wait on a decision on the converter until the 50amp fuse is replaced. 

Better get 2 fuses in case the new fuse blows.

BTW, the wiring diagram is listing what you are calling a 50amp fuse as a "breaker".  It could be a self resetting circuit breaker, instead of a fuse. 

I'm not much help on converters,  other than to say if you replace the converter, spend a few extra bucks and buy a 3 or 4 stage converter.  I have not had an RV with a functional converter since 2007.  My last 3 RV's either came with an inverter/charger, or I installed an inverter/charger and disconnected the converter.

Couple more questions, if you will bear with me.....i notice that converters (powermax brand) on amazon come with a  4 stage smart battery charger built in for $289 or a cheaper one for $189 that doesnt mention anything about a charger.
Question 1. I understand about smart chargers but are they neccessary, as in $100.00 more or will the batteries stay charged on an old style converter?
Question 2. If i place a volt meter in the wire running from the converter to the batteries will it adversely  affect charging in some way?
Question 3. Wheres the best place to install an amp meter so i can monitor battery draw?
Thnx again everyone for the help and advice, great forum.

Royeyford said:

Couple more questions, if you will bear with me.....i notice that converters (powermax brand) on amazon come with a  4 stage smart battery charger built in for $289 or a cheaper one for $189 that doesnt mention anything about a charger.
Question 1. I understand about smart chargers but are they neccessary, as in $100.00 more or will the batteries stay charged on an old style converter?
Question 2. If i place a volt meter in the wire running from the converter to the batteries will it adversely  affect charging in some way?
Question 3. Wheres the best place to install an amp meter so i can monitor battery draw?
Thnx again everyone for the help and advice, great forum.

Click to expand...

1.  I recommend the 4 stage converter.  However if you are not going to dry camp or boondock and you will almost always be using the RV, then the single stage converter will work.  However you should not leave the house batteries on the single stage converter for months at a time.  Some converters will keep 13.4V on the batteries and may boil the water out of them.
2.  Are you wanting to use the volt meter to measure the amount of current coming from the battery?  Most hand held volt meters are only able to handle a couple of amps of current.  About as much as a single light bulb in the RV.
3.  If you want to monitor the battery current and useage you want to install a shunt on the ground side of the house batteries.  The shunt then has 2 small wires going to the battery monitor.  The Trimetric monitor is the one I use:  http://www.bogartengineering.com/products/trimetrics/  However if you are not going to use the house batteries to dry camp or boondock more than 1 or 2 nights between connecting to shore power then you don't need the monitor. 

You said the converter only shows 11.something but the batteries 13.something.

What make and model converter?

Why do I ask.... Some converters the output is raw, unfiltered Rectified A/C.. You read the RMS but the batteries get the PEAK..  thus, the volt meter reading is 0.707 the peak (1/2 the square root of two) so you get a lower reading on the voltmeter.. A peak reading meter will show the peak voltage.  I have both kinds here.

However, many older converters and all of them that output raw unfiltered rectified A/C (It's still DC but it has a strong AC part) .. Well they really deserve a good upgrade

Stand alone go with progressive Dynamics 9200  Built into the power panel make it a 4600, still PD however.