Magnum Inverter shows Low Voltage with engine running...OK on Shore or Generator - 2005 Endeavor

[Will52]

Magnum inverter shows fault and low voltage going down the road. NP/OK on shore power and Genny running, is there a relay that's open from the engine alternator? The gauge is showing 13 volts +. NP with truck batteries.

[MyronTruex]

It sound like you definitely have a charge line path that is open.

Without pulling up schematics I will take a stab. You could have a "relay" that is not functioning or a circuit that drives it but you likely have a diode isolator. This is a simple Y device. That is, Alternator feeds one end and then splits out two ways. One of those ways could be bad.

In any case some pictures of your battery compartment and electrical compartments will sort it out quickly. I should take just a couple of readings to get to the root of the problem.

Just for grins, since you will be taking pictures I suspect, start the RV and then press the Aux start button and hold it. Prop it or get some help to hold it and then see if the Magnum likes that. This will provide some input and help eliminate at least one component. 

Edited May 29, 2023 by myrontruex
spelling

[Tom Cherry]

18 hours ago, Will52 said:

Magnum inverter shows fault and low voltage going down the road. NP/OK on shore power and Genny running, is there a relay that's open from the engine alternator? The gauge is showing 13 volts +. NP with truck batteries.

I hate to differ with Myron, but the answer is....

Your House Batteries are low.  REALLY LOW.  Look at the print below.  we don't really have a good set of complete 2005 Endeavor (also same as Diplomat) prints.  BUT, this shows the layout.  Your Chassis Batteries WILL NOT nor were they intended to....Charge or maintain the House Bank.  There is a "Solenoid" between the Engine (Chassis) Batteries.  BUT, that is the Boost Switch so you can get power from the House to assist starting the Engine.

You need to get the House Batteries properly charged.  If you have solar, then you might need to disconnect each set of batteries at the controller.

I really can't explain, other than....Low Battery while driving means....the House Bank is LOW.  So, if they are "Charging" or OK when on Generator or Shore....my gut is that you have some issues with the batteries and all the charging current is not really charging them. Start with the basics of checking the House bank.

There is a current thread on this.....When on SHORE....whether a Dynasty or an Endeavor....the House will be charged.

Scroll down through it.  There is a file on Battery 101 and download and read it.  

I'll also offer one more comment.  IF you use a Jumper Cable....which is the SAME as pushing in the Boost Switch (that assumes the House batteries have enough voltage to energize the solenoid)....then I THINK the Low Voltage MIGHT go away.  BUT, when you get a Magnum into a funk and it trips or turns off, sometimes you have to do a SOFT reset. You can google that.

I would connect the jumper from the positives of each bank (Ground is not needed) and then check it out.  If that didn't fix it....then do the soft reset....and try.

 

2005 Endeavor Battery Layout - Page 297 Manual.pdf

[Will52]

I'm the second owner and have some prints will share when I can. Check batt's tomorrow with shore power off. Last checked floated 4 ball all cells. 

[Larry Laursen]

Most likely your Trombetta interconnect relay is bad.  The house batteries should be charged while driving.  However, the Trombetta connects the batteries together and is controlled by the Intellitec interconnect relay delay (IRD)controller.  The stock Trombettas have copper contacts that corrode and good bad.  With the engine running and the coach disconnected from shore power, check the voltages on both sides of the Trombetta relay.  If there is more than about 0.2 volts difference between the readings, the Trombetta is bad.  Also check the voltage across the small terminals.  It should be about 12 volts. If not, the IRD may be bad.

[Tom Cherry]

11 hours ago, Larry Laursen said:

Most likely your Trombetta interconnect relay is bad.  The house batteries should be charged while driving.  However, the Trombetta connects the batteries together and is controlled by the Intellitec interconnect relay delay (IRD)controller.  The stock Trombettas have copper contacts that corrode and good bad.  With the engine running and the coach disconnected from shore power, check the voltages on both sides of the Trombetta relay.  If there is more than about 0.2 volts difference between the readings, the Trombetta is bad.  Also check the voltage across the small terminals.  It should be about 12 volts. If not, the IRD may be bad.

I defer to Larry.  He is an expert on the older models and the evolution from no charging to IRD to BIRD (Bi Directional)....as in the Shore, via the Inverter and a different type of solenoid and control system....will charge BOTH sets when plugged in....as well as BOTH being Charged when driving.

The Manual was not clear and stated that the starting batteries were charged while driving.  If the solenoid (AkA the Trombetta) is controlled by the Intellitec IRD, then that is most likely the issue.  You CAN, though, test this by using the Jumper Cable.  If that eliminates the issue, then there has to be ONE of two things going on...

The Trombetta is defective.  If I recall, and Larry can chime in, most folks purchase the Upgraded Trombetta with the SILVER contacts which last longer.  

As to the Intellitec IRD, here is a PDF on it.  Readily available and a simple install. 

https://intellitec.com/wp-content/uploads/2019/04/53-00629-000.pdf

Locate the wires going to the solenoid from it...and get the PN....should be close....if different, google the PN and get the instructions on it.

 

 

[Larry Laursen]

Here is the Trombetta spec sheet with the part number you want.

You can see it here: Trombetta 114-1211-020 12 Volt Bear DC Contactor: Motor Contactors: Amazon.com: Industrial & Scientific

TRPartNumbering-BearHL.pdf

[MyronTruex]

Well, do yourself a favor and grab a voltmeter. A couple of pictures will help sort things as well. Modifications by previous owners can lead to a lot of speculation.

Have you tried my suggestion or holding the Aux button down and checked the issue? 

 

Edited May 31, 2023 by myrontruex

[bobdinsmore]

Just as a curiosity, what was the resolution?