CJ7harv2018

On 1/13/2020 at 5:39 PM, larry.jervis@att.net said:

Steven,

My Magnum MS2012 (2000Watt) normally charges in Bulk and Absorption mode of 14.6 to 14.8 so the voltage you seeing seems to be correct. Now remember that every time the power is disconnected and reconnected the Magnum Inverter/Chargers starts the programmed charging cycle. The default charging cycle is 120 Minutes but can be changed through the Setup keys on the remote.  If the charge cycle was interrupted by either loss of power (turn generator off if on that power source or shore power) the charge cycle when then Magnum is powered back up will start the 120 minute charge program but the Bulk Rate charge will be less as the % charge of the batteries will be higher. This just extends the Float rate charge after the Absorption rate is complete.

As I look back on the first post photo showing the Aladdin 14.1 and  Scangauge  13.8`  Battery Charge Voltage they are .4 volts  . Now the Aladdin voltage information is coming from a different connection than the ScanGauge. I would check all the Ground connections in the dash, battery compartments, Chassis and all run panels (front and Back). I chased a issue with gauges in the dash and turned out a loose ground. After that incident I went through the entire coach and tightened every ground, even pulled most on the Chassis and cleaned the connections then put dielectric grease on the connections to make sure there was a good ground. After that exercise my issues with the dash along with correct voltage reading between the Batteries. Alternator, and ScanGauge were correct.

Note: The Charge Voltage on the Magnum remote is showing the state of the House Batteries not the Chassis Batteries as when the Generator is on the Chassis Batteries are isolated from being charged from the generator, that is why there is a difference in the dash voltage and the Magnum remote.

There is also a 'Charge Fault Relay' that is powered from Aux Terminal on the Alternator that turns the 'Alt Charge' light on the dash. The normal mode is when the Alternator's output is at normal voltage 13.8 -14.5 the Aux terminal is outputting 6 volts (that is the normal output voltage). This 6 Volt output energizes the coil in the ' Charge Fault Relay' that turns the 'Alt Charge' light on the dash off and when the engine is not running but the key is in the run position the 'Alt Charge' is Lite. In the situation that the first photo shows is the Alternator is outputting 14.1+ Voltage but the 'Alt Charger' Light is on. This means that either the Charge Fault Relay is bad (mine went bad this last summer) or the Aux output on the Alternator is Bad but I would not bet on that or the 14+ volt on the dash gauges would not be correct. Now the wire on the Aux terminal on the Alternator may have come loose or it is just the 'Charge Fault Relay' have failed.

Note: The Charge Fault Relay has a (6 Volt Coil) not a 12Volt, as the volt from the Alternator to the relay is 6Volts. This Relay is not going to be available at the most local parts houses, I will try to find the part number for the relay I purchased (purchased from a Cummins dealer as used in Diesel trucks) so to help you location a replacement. Once you find the relay just remove it and the light will turn out until you find a replacement relay, the part # and coil voltage will be marked on the top or side of the relay. The relay is a Black square plugin style relay, mine was located in the Front Run panel (Driver side) on the right side wall when looking into the bay, Yours may be located in different location so you will need to hunt for it.

Loose grounds can cause numerous issues and with the amount of bouncing and movement our coaches receiving going down the road is hard enough on the connections (just imagine putting your house on a trailer and towing a thousand miles what kind of shape it would be in) now add all the environment issues (rain, heat, cold, humidity) it is a wonder at times these coaches don't have more issues.

I have spent many days being proactive with my coach (original owner) checking and rechecking and always seem to have sometime that needs to be fixed or adjusted. I worked for years as an electrical controls design and troubling tech on high speed production equipment and loose connections were one of the most common source of failures or those phantom failures that drive everyone crazy.

Sorry for the long post but since there is not a lot of documentation around for the coaches (I was lucking mine came with a  set of electrical diagrams - these are not complete as they cover many different models but are helpful 90% of the time). If I can help you with any questions please advise.

Larry

2004 Diplomat 30'

Hi could you please provide a picture of the relay and it’s location. I’m having the same issue.