12v dc not working on battery

[RLLawrenceJr]

Hello Everyone!

I have a 2000 376 FB SS that I live in full time. The other day I lost shore power for a few hours and for the first time my 12 volt system did not automatically kick in.

I have 2 6v golf cart batteries and both batteries show 6 volts. I tightened the nuts on both batteries. There is 2 fuses on the wires coming off the batteries and there is 12 volts after both fuses. I have tried to find some sort of reset for the 12 volt system but I can't find one.

All of my 12 volt systems work when plugged into shore power.

If anyone has any ideas I would love to hear them..

Thanks

[JimD]

Best guess is that there is a break in the wire feed between the batteries and the converter. Since your 12 volt items work when plugged in, the converter and the circuitry from there on is OK. I would also assume that your batteries are not being charged when on shore power. Your rig may or may not have a battery disconnect switch which should be checked if present.

The batteries typically will connect directly to the converter through a heavy gauge battery cable. The negative on the battery probably is tied to frame ground although it is possible that it is also fed to the converter through its own cable.

Since you stated there are fuses at the batteries and they are both good, I would first look at where the cables go from the batteries. If one goes to the frame verify that there is a real good connection to the frame. There have been instances where ground wires have broken off or loosened.

If that checks out I would look at the battery cable connection at the converter. Clean and tight.

These are things that immediately come to mind.

[RLLawrenceJr]

Originally Posted by JimD

Best guess is that there is a break in the wire feed between the batteries and the converter. Since your 12 volt items work when plugged in, the converter and the circuitry from there on is OK. I would also assume that your batteries are not being charged when on shore power. Your rig may or may not have a battery disconnect switch which should be checked if present.

The batteries typically will connect directly to the converter through a heavy gauge battery cable. The negative on the battery probably is tied to frame ground although it is possible that it is also fed to the converter through its own cable.

Since you stated there are fuses at the batteries and they are both good, I would first look at where the cables go from the batteries. If one goes to the frame verify that there is a real good connection to the frame. There have been instances where ground wires have broken off or loosened.

If that checks out I would look at the battery cable connection at the converter. Clean and tight.

These are things that immediately come to mind.

Thank you.

Where the ground connects to frame it is pretty corroded. I will take it off and clean it. If my trailer has a battery disconnect, I do not know where it is.

I do wonder about the batteries being charged because it is cold here and both batteries have a solid 6 volts on them. Following the wires will not be easy, they go into the floor and walls pretty quickly.

Thanks for your help.

[Rustic Eagle]

RLLawrenceJr,

Welcome to JOF

If you don't have a 30amp fuse near your battery, look for a 12v circuit breaker that may be mounted next to a junction box mounted on the TT frame a few feet from the battery.

The circuit breaker looks like the following and there will be a little black reset button on the side ......



Bob

[Jagiven]

There should be three 30 amp fuses. One at the battery, and two at the fuse box, o e for reverse polarity protection and one for current. I would double check them. Then I would check the ground wire connection on the frame for the batteries.

A 6.0v is a discharged battery, but it should eliminate your lights.

[RLLawrenceJr]

Originally Posted by Rustic Eagle

RLLawrenceJr,

Welcome to JOF

If you don't have a 30amp fuse near your battery, look for a 12v circuit breaker that may be mounted next to a junction box mounted on the TT frame a few feet from the battery.

The circuit breaker looks like the following and there will be a little black reset button on the side ......



Bob

Thank you. In my research before posting here I read about one of those and looked for one. There is snow here so I am skirted but took off part of the skirting and looked under the trailer. The wires come through the siding and within a ft go up into the floor. There is nothing but wires. I just went back out to double check the wires outside. I can't see a breaker like that.

[GHen]

Can you check the batteries again, combined they should be 12.7 or so, separate they should be 6.4 or so. If they are 6.0, they are below minimum capacity and may not be getting charged when you are on shore power. 6.1 should be considered dead.

[RLLawrenceJr]

Originally Posted by GHen

Can you check the batteries again, combined they should be 12.7 or so, separate they should be 6.4 or so. If they are 6.0, they are below minimum capacity and may not be getting charged when you are on shore power. 6.1 should be considered dead.

I did not realize that. They are bot at 6.0

Maybe they are dead.

[RetiredOne]

Originally Posted by RLLawrenceJr

I did not realize that. They are bot at 6.0

Maybe they are dead.

This chart might help:


Also, some digital voltmeters can be off by a few tenths of a volt, so if you have more than one, compare them.

[GHen]

Are you using a volt meter of some sort? To check the combined, check between the positive on one battery and the negative on the other battery. Should be between 12.2 and 12.7.

Even though they are 6v they combine for 12. If the meter in the rv shows 6, they are dead. It could be they are not getting charged.

[GHen]

Retiredone and I are on the same page, just different charts.
I like the 6v numbers on his.

[RetiredOne]

Originally Posted by GHen

Retiredone and I are on the same page, just different charts.
I like the 6v numbers on his.

If he has 6 volts on each battery or 12 volts between the two, he has batteries close to dead. He needs to take a voltage reading when not plugged into shore power, then plug into shore power, and see if the voltage jumps up, which will show if his charger is working.

Also, the OP has a rig built in 2000. Like JimD said, he could very well have a bad or corroded ground connection, which is causing his issues. That's VERY popular with older rigs.

[GHen]

Agreed.

Key number on the charts is 50%. Anything below 50% means the batteries are being damaged and may not be able to fully recover.

[RLLawrenceJr]

You guys are incredible!! Thanks for all the information.

I worked on TOW missiles and the weapon systems of the Apache helicopter when I was in the Army. You would think that I would know these things.

I feel pretty sure that it is the batteries that have died. I have discovered that my converted is a decent one but as it is set up it is only a single stage charger. Progressive Dynamics PD9140A. According to their site I need a "Charge Wizard" that plugs into the converter and makes it a smart charger.

So the Batteries have been on the trailer for 2 or 3 years (memory is gone too) almost constantly connected to shore power. I have not checked them or maintained them. My fault.

I am charging another 12 deep cycle battery that I have and will test the system with it. Now that I know that 12 volts is not 12 volts and have the proper charts to test the batteries, I will be monitoring my batteries more closely. I am going to pull the two golf cart batteries, let them thaw, check the water and charge them with a smart charger and see if they will come back to life. Not much hope, though.

I really appreciate all the help. I have learned a lot in this exercise. I will get back to regular PMCS to keep my rig working well. When the power goes out is not the time to check the batteries.

[RLLawrenceJr]

"Welcome to JOF

If you don't have a 30amp fuse near your battery, look for a 12v circuit breaker that may be mounted next to a junction box mounted on the TT frame a few feet from the battery.

The circuit breaker looks like the following and there will be a little black reset button on the side ......"


I don't see one of these anywhere on my trailer. Do you think it would be a good idea to add one?

[RLLawrenceJr]

The Saga continues. I put a fully charged battery outside and my 12v system does not work when the shore power is cut.

Cleaning the ground contact is next.

[Rustic Eagle]

Originally Posted by RLLawrenceJr

snip......I don't see one of these anywhere on my trailer. Do you think it would be a good idea to add one?

Since you have 30amp fuses right after the battery(s), a circuit breaker would be added protection, but not required at the moment.

I might have missed it in a prior post..., but I assume "all" 12v fuses in the breaker box are visually good. As mentioned earlier, you may need to confirm (with shore power disconnected) at some point that your 12v connections are tight behind the breaker box.

Bob

[TCNashville]

Originally Posted by RLLawrenceJr

Cleaning the ground contact is next.

A bad ground can cause all kind of strange electrical issues. Hopefully when you clean the ground it'll solve your issues. As stated above make sure all 12v fuses are good in the box.

[RLLawrenceJr]

Originally Posted by Rustic Eagle

Since you have 30amp fuses right after the battery(s), a circuit breaker would be added protection, but not required at the moment.

I might have missed it in a prior post..., but I assume "all" 12v fuses in the breaker box are visually good. As mentioned earlier, you may need to confirm (with shore power disconnected) at some point that your 12v connections are tight behind the breaker box.

Bob

If I redo the wires I may put new fuses in.

I have tested all of the 12v fuses, fuses box and on the converter with a multimeter. 12v on both ends. I am going to clean the ground and then start walking the wire back with a 12v probe to see what I can find.

[Levinehikeski]

Put fuses in no matter what.

Using a multimeter in the ohms setting, put one lead on the negative terminal (battery end of the ground cable), put the other on a bare metal part of the frame. If you don’t get .1 ohm or less, clean up the spot where the ground wire attaches to the frame. That should at least get your 12v system able to work. If not, not sure without knowing/seeing a few more things