12V Interior Lights Problem

Lukeaa · 02-27-2008, 05:49 PM

2007 Monaco Diplomat 40' SFT. Lots of 12V interior lights.

The voltage on the interior 12V lights is 10.5 to 11.0 volts. They go to bright, then dim, constantly. The Magnum ME2012 inverter/charger is charging the batteries to 13.4V, but something is then dropping the interior voltage to 10.5V.

What is between the charger and the interior lights that would drop the voltage in this way? We will be at the Monaco dealer on Friday, but it is driving me crazy in the mean time. The coach is three months old.

Lukeaa · 02-27-2008, 05:49 PM

2007 Monaco Diplomat 40' SFT. Lots of 12V interior lights.

The voltage on the interior 12V lights is 10.5 to 11.0 volts. They go to bright, then dim, constantly. The Magnum ME2012 inverter/charger is charging the batteries to 13.4V, but something is then dropping the interior voltage to 10.5V.

What is between the charger and the interior lights that would drop the voltage in this way? We will be at the Monaco dealer on Friday, but it is driving me crazy in the mean time. The coach is three months old.

Ray,IN · 02-27-2008, 06:01 PM

Poor ground causes the vast majority of 12V electricial problems. I suspect your's is also.

Lukeaa · 02-27-2008, 06:13 PM

The inverter has a good ground. Where would the invertior lighing system be attached to ground?

**RV Wizard** · 02-28-2008, 01:10 AM

Luke, I would start at the house battery bank and check all connections and water level in cells. Then check the Main ground as Ray has suggested. The main ground for individual branch circuits will be a the 12 volt distribution panel where you will have fuses and/or breakers. Check those too. If all are good then I would be checking the condition of the house batteries individually. If you have a shorted cell the charging section will cycle on and off to prevent damage to itself. Once you have eliminated these possibilities then have your dealer fix it under warranty. Keep us posted as you go.

NeilV · 02-28-2008, 01:15 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Lukeaa:
The inverter has a good ground. Where would the invertior lighing system be attached to ground? </div></BLOCKQUOTE>

You would have to consult the manufacturer as each does their own thing on running the grounds otherwise start at the house battery and follow the ground lead to the distribution block.

A check would be to run a wire from the negative terminal on the house battery to your meter and then check the positive lead going into the troublesome light. If you are then getting the correct reading the problem is the ground. If not then it is the positive side that is the problem. To double check this connect to the positive terminal on your house battery and the negative lead on the light and see what the reading is then. If this reading now shows correct voltage then the problem is on the positive side of the circuit.

Note that you need to be carefull not to cause a short circuit when using long test leads and it would be good to have a helper assist you in keeping things in the clear so as not to get burned or start a fire.

Lukeaa · 02-29-2008, 07:52 PM

We stopped at a Monaco dealer in Texas today and they diagnosed the inverter as internal arcing and overheating. Monaco OKed a new one. The dealer had one in stock and three hours later it was installed. All of the problems are gone and I am a happy camper.