ATF: ElkRidge - DC power fluctuations

dle

Member
Help - all of our DC power started to fluctuate - the lights dim and the fans slow down then the lights go to normal brightness and the fans go to normal speed then it starts all over again. The dealer checked the, converter and said everything was normal. We are plugged into shore power and all ac power works great.
 

cookie

Administrator
Staff member
It really does sound like the converter or a bad battery. Out may not be holding a charge.
But there are a couple of things you can check.
Number one would be to check the connections at the battery. I would also check all the neutral (white wires) on the neutral buss bar. Make sure they are all tight.
When the lights are dim, check the voltage at the battery. You should be at 12+ volts.
Then check when the lights are bright. This would be when the converter is charging. You should see 13+ volts.
Let us know what you find.

Peace
Dave

Sent from my DROID RAZR using Tapatalk 2
 

danemayer

Well-known member
The power converter output voltage fluctuates depending on how it's charging the battery. I believe it has 3 output levels. I don't think any of them would account for slow fans however.

Here's a link to a diagnostic guide and block diagram of the 12V system. The specific problem isn't covered by the diagnostic, but following it may still help you isolate the problem.
 

Bob&Patty

Founders of SoCal Chapter
What fans are you refering to. As far as I know, the ceiling fan is 110V....the heater and such are 12V DC.
 

dle

Member
output from the converter showed 13.7 v The battery showed 13.7 v. The fans i was talking about are the range vent and the bathroom vent fan. Both are 12 v fans. We checked the all the connections to the battery and converter as well as connections on the ground buss bars. all were tight. we are going to install a meter so that we can monitor the voltage quickly when the lights dim.
 

danemayer

Well-known member
output from the converter showed 13.7 v The battery showed 13.7 v.
Did you measure the battery voltage with the converter turned off? If not, flip the circuit breaker that powers the converter and check the battery again. Something must be sucking up the power from the converter. A short in the wiring would normally blow a fuse, but if the short is internal to the battery, maybe it's drawing down the voltage supplied by the converter.

Btw, I'm not an electrical engineer, so these are guesses.
 

dle

Member
Did you measure the battery voltage with the converter turned off? If not, flip the circuit breaker that powers the converter and check the battery again. Something must be sucking up the power from the converter. A short in the wiring would normally blow a fuse, but if the short is internal to the battery, maybe it's drawing down the voltage supplied by the converter.

Btw, I'm not an electrical engineer, so these are guesses.

Checked battery with power off 13.7v I also did a load test and the battery only dropped to 12 v. I think the battery is just fine and is getting charged properly

I don't know what to do next
 

danemayer

Well-known member
Next thing I would do: cut all power, including battery and shore power. Unscrew the fuse panel, pull it toward you and inspect the connections on the back. Maybe there's a loose main supply or ground wire.

When you say you checked the connections on the ground buss bars, are you talking about where the negative terminal of the battery connects to the frame ground?
 

dle

Member
I have already checked behind the fuse panel and on the converter. All connection are tight. Checked the buss bar at the converter and the one in the battery compartment. I am not sure where the frame ground is.
 

danemayer

Well-known member
I have already checked behind the fuse panel and on the converter. All connection are tight. Checked the buss bar at the converter and the one in the battery compartment. I am not sure where the frame ground is.

If you haven't checked it already, see if you can follow the large wire from the negative battery terminal to its ground connection.
 
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