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2006 Monaco Executive Ranier IIIF (3 slide, 2 front and 1 rear). Having issue with chassis batteries and DC output of Inverter (can't find fuse)


limycenter
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Go to solution Solved by Tom Cherry,

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Hey Everyone

My Problem:

House does not have working 120V or 12V when plugged in or on generator until I short the batteries together with ignition on at the dash switch.  When i hit the switch with the ignition on, the inverter will kick on/pass 120V to house along with DC to the 12V system

So my thinking is the fuse connecting the inverter to the house batteries is bad......but that might be another squirrel that I am chasing. I can't find the big fuse that connects the house batteries to the inverter. 

  • went to leave camp and coach wouldn't start (was plugged in, charger was in float mode)
  • finally got started and inverter was reading .5V on house batteries so wouldn't invert
  • batteries read 13.4V at the battery (I installed lithium 2 years ago)
  • in rear fuse/relay box, the house batteries are not making it to the box
  • Arrive at new destination and plug 50A into shore power but don't have 120V on the other side of the inverter side (inverter/charger won't pass the 120V) and charger won't supply DC
  • i am able to "kick-start" the inverter by shorting the chassis to house batteries using switch up front when the ignition is ON.....EVERYTHING WORKS, 12V and 120V gets passed through the inverter.  All is good until i lose 120V power then i have to kick-start the system.  The house batteries are NOT getting charged
  • I assumed that the battery disconnect switches were bad and replaced them after lots of screwing around ..... they are in a painful to replace area and hard to acquire since they are 4 post and wired in a unique way
  • Stock inverter (was replaced 3 years ago right before I bought) but its still the stock model 3K Magna (NOT HYBRID)
  • House batteries are good, inverter IS working ---- I unhooked the inverter from the coach and direct connected a battery and it worked (started charging the batteries)
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What lithium batteries do you have?  I recently installed 3 SOK 206 Amp Hour batteries.  Today, while on battery, I ran the microwave and the Keurig coffee maker.  Lost all 12v and inverter.  The SOK batteries were dead.  I had caused a high amp disconnect and the BMS in one or more of the batteries shut down.

The way to fix this is to briefly add a charging source to the lithium batteries, which will wake up the BMS and clear the fault condition.  I did this using jumper cables from the chassis battery.

When you use the "batt boost switch" from the drivers position, you are briefly putting a charge voltage on the lithium batteries.

When this happens again, I suggest checking the voltage at the lithium house batteries when the 12v and 120v inverter circuits are not working.   Then, when you use the batt boost switch and get things working again, check the voltage again.

Of course I don't know what's going on in your system.  You may or may not have a fault condition that is shutting down the BMS in your lithium batteries, but you may want to check.

Dwight

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It appears DC power is not getting to the inverter from the lithiums. How the engine batteries get to the inverter with the boost on is a bit of a mystery but who knows how your system has been modified? 

In any case, I would disconnect the shoreline. Remove the negative lead/s from the engine batteries so they are isolated and will not give you a false reading.

Work your way with a voltmeter from the Lithiums to the inverter. You may find a large amperage fuse mounted someplace that is hard to see. In any case, it should not be difficult to chase those heavy-duty wires. 

If you need/want to get a measurement on a wire somewhere midsection, for example, sharpen your positive probe using a bench grinder so it has a very sharp needle point. Tape up all but the last 1/4 inch of the probe. Now you can pierce the heavy insulation on the wires and they will self-heal basically when you take the probe out. A good ground is an absolute must when metering of course. 

With two battery paths in your setup, it would be very easy for a digital voltmeter to fool even the most experienced tech. 

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These are Valence U27-12XP.  They do not have built-in BMS.  

11 hours ago, Dwight Lindsey said:

What lithium batteries do you have?  I recently installed 3 SOK 206 Amp Hour batteries.  Today, while on battery, I ran the microwave and the Keurig coffee maker.  Lost all 12v and inverter.  The SOK batteries were dead.  I had caused a high amp disconnect and the BMS in one or more of the batteries shut down.

The way to fix this is to briefly add a charging source to the lithium batteries, which will wake up the BMS and clear the fault condition.  I did this using jumper cables from the chassis battery.

When you use the "batt boost switch" from the drivers position, you are briefly putting a charge voltage on the lithium batteries.

When this happens again, I suggest checking the voltage at the lithium house batteries when the 12v and 120v inverter circuits are not working.   Then, when you use the batt boost switch and get things working again, check the voltage again.

Of course I don't know what's going on in your system.  You may or may not have a fault condition that is shutting down the BMS in your lithium batteries, but you may want to check.

Dwight

 

The plot is thickening.......

I have 1 house battery plugged in.  But the disconnect switch is in the OFF position.  Last night, I was wakened from my slumber for a low battery warning by the Aladdin system (12V on the Lithium).  

I went out and disconnected the house battery.  But now my door keypad and keys do not lock the coach.  The inverter is still putting out DC to the coach. 

I have installed a Battery Isolation Manager in place of the fatboy relay to keep the batteries charged.......

https://battlebornbatteries.com/product/lifepo4-battery-isolation-manager/ 

36 minutes ago, myrontruex said:

It appears DC power is not getting to the inverter from the lithiums. How the engine batteries get to the inverter with the boost on is a bit of a mystery but who knows how your system has been modified? 

In any case, I would disconnect the shoreline. Remove the negative lead/s from the engine batteries so they are isolated and will not give you a false reading.

Work your way with a voltmeter from the Lithiums to the inverter. You may find a large amperage fuse mounted someplace that is hard to see. In any case, it should not be difficult to chase those heavy-duty wires. 

If you need/want to get a measurement on a wire somewhere midsection, for example, sharpen your positive probe using a bench grinder so it has a very sharp needle point. Tape up all but the last 1/4 inch of the probe. Now you can pierce the heavy insulation on the wires and they will self-heal basically when you take the probe out. A good ground is an absolute must when metering of course. 

With two battery paths in your setup, it would be very easy for a digital voltmeter to fool even the most experienced tech. 

 

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WOW….so this supplements what was posted.

The Magnum will NOT transfer or pass through any 120 VAC unless it is ON and there is a battery hooked up.  Battery doesn’t need to be great, but at least a hint of a charge.  
 

The Battery Boost switch, as suggested, is giving you a flash or surface charge.  That means that the Magnum can then complete the startup and will use its internal ATS to pass power into the convenience outlets.  NOW, if the AC’s work, you DO have good Shore Power (or Genny).  The living area outlets, icemaker outlet and microwave are powered through the Inverter.  Odds are you have a subpanel with these 115 VAC a breakers.  That is the power coming from the SHORE lines.  You probably have TWO 30 amp breakers in the main AC panel.  They go directly from the Main ATS to the 50 Amp main.  Then the inverter is called a Dual IN & Dual Out setup.  So the output or outgoing power from the Inverter goes to the Sub panel.  When the inverter is inverting, you only get 3,000 watts of power, but when the shore is plugged in (or Genny), then the Magnum will deliver more wattage.  

You can do all sorts of testing.  But one easy test as well as a “need to use the MH” is a simple Jumper cable from the Chassis Positive to the House Positive.  If you have AC (microwave and outlets and such), you should see the Magnum working as normal.  If that is the case, then searching for the fuse is futile.  That fuse is a short stubby fat round fuse.  It will have a 4/0 cable coming into it.  Since you have a 3,000 watt inverter, I don’t know the size.  The 2000 watt has a 300amp, so in theory, yours should be a 450….your Magnum Manual as well as your High Current Monaco print will tell you the size…or you pull it out.  I think it is fine…but the jumper cable will tell you.  The Jumper Cable is NOT BYPASSING the fuse, it is ONLY giving you a REAL battery that the Magnum can “read”.  If the Magnum is still OFF after the Jumper cable is in place, you DO have a fuse problem.

My next comment is just a general observation.  Your problem MAY be in the inverter or maybe the setup.  I assume that you called magnum and asked them how to set up the Magnum for the Lithium bank.  Many folks have had issues with that.  A 16 year old, or even a newer Magnum may not be the best technology for charging and maintaining Lithium batteries.  If you jp use the Jumper cable, you WILL get, I think, charging of the Lithiums as the Magnum will be, through the Big Boy, charging the Lithiums.  Likewise, if you drive a while with the jumper in place, it will allow the alternator to charge the lithiums.

First….eliminate the fuse being blown or the issue….via the Jumper cable.  

Next, call Magnum and discuss and let them walk you through the setup.  From what you say about the chassis batteries being dead, the magnum charging is not working….why NOW….I can’t tell you.  SPECULATION….the improper or lack of consistent  charging of the lithiums has finally reached critical mass and the Magnum says….I can’t do this.  And the Lithiums are now depleted or maybe worse…. You have not commented on whether you have power in storage or when not in use.

good luck and keep us apprised of your progress and the final solution.

 

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Tom (and myrontruex and Dwight)

Thanks for the replies.  I have had these batteries for 2 years.  When I first installed them I contacted Magnum, bought an updated monitor unit and setup a CC/CV charging scheme that was compatible with the Valence spec sheet AND the magnum charger/monitor combo.  I am able to monitor the batteries via a custom cable and computer.  They are healthy and working.  

I live in this rig full-time and am almost always plugged into shore power.  I leave the charger in Float at 13.6 (which is find for the batteries according to the spec sheet).  

I jumped the house to the chassis batteries and the charger DID not see the low battery voltage and start charging ....... i did not turn off AC to test inversion method.  

while driving about 2 days ago, the front switch did get the inverter working (i am assuming off the truck batteries). 

I will find the fuse to see if that is the cause since when i hardwire a battery to the inverter......it will charge the battery.  

Clint

 

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42 minutes ago, limycenter said:

Tom (and myrontruex and Dwight)

Thanks for the replies.  I have had these batteries for 2 years.  When I first installed them I contacted Magnum, bought an updated monitor unit and setup a CC/CV charging scheme that was compatible with the Valence spec sheet AND the magnum charger/monitor combo.  I am able to monitor the batteries via a custom cable and computer.  They are healthy and working.  

I live in this rig full-time and am almost always plugged into shore power.  I leave the charger in Float at 13.6 (which is find for the batteries according to the spec sheet).  

I jumped the house to the chassis batteries and the charger DID not see the low battery voltage and start charging ....... i did not turn off AC to test inversion method.  

while driving about 2 days ago, the front switch did get the inverter working (i am assuming off the truck batteries). 

I will find the fuse to see if that is the cause since when i hardwire a battery to the inverter......it will charge the battery.  

Clint

 

Bummer, but you did all the right things, which some have NOT, when going to Lithium.  Please don't take my comment as "talking down"....we have had this issue and folks just popped in Lithiums and went on....

OK....  In your prints and from the Magnum Manual, there is a 400  Amp Fuse.  It LOOKS Square or Rectangular.  The Monaco Prints, which I downloaded are clear and legibile.  but the outlines of the buss connectors and such on the main board are hard to follow on the prints. I THINK that the fuse would be on the main board....  About mid way into the prints there is DR3 3801004 (Schematic High Current Low Voltage).  That is the block outline.  From THAT drawing, it LOOKS like your fuse may be on the UNSWITCHED side of the Disconnect switch.  But there are subsequent drawing for different banks and also for multiple inverters (these prints were for Dynasty and all higher models).  SO, my advice....look at the one I found first and then start chasing cables.  Whether it is one the Switched side or a HOT direct connection, you need to find it and see if it is OK. 

Past that, you have, I think, reached the same conclusion.  The Inverter is somehow disconnected from the Battery Bank and when you actually Jumper the connections....the Chassis Battery is what the Inverter is seeing and all is well.  NEVER trust a Monaco Cable. The advice of the experts is to do a Voltage Measurement across each connection....that means you have to use a Jumper to get back to the "back" sometimes.  If you measure the terminal (batter connector) using the VOLT setting UNDER LOAD, then you can see the drop.....there should be barely 0.03 (3 hundredths) drop....I suspect....and that is pure GUT feel, that you have a bad battery cable terminal.  By Battery Cable, I mean any 4/0 or 2/0 high current cable from the Battery Bank to ALL the downstream connections until it gets to the inverter.

ONE REALLY OFF THE WALL comment.  IF you have a BAD Battery GROUND from the House to the Chassis Stud, then that could be the issue.  Easy enough to test or almost as easy to FIX.  If you run your Jumper from the House Ground to the Chassis Ground....and the Inverter works....then do to the HOUSE GROUND Stud....or follow it.  I had a LOW voltage Low current draw up front that would not crank the genny.  It was the House Ground Stud connection.  I loosened and cleaned and such.  BINGO....no issues in over 10 years.  I found that if I Firmly SHUT the house battery tray it would not crank.  BUT, if I moved it and then PUSHED on it, it worked.  I measured the resistance between a GOOD ground (on the Chassis) and the House Ground or negative.  I had a few ohms.  BUT, the same measurement on the Chassis....was ZERO.  I got it to stabilize....and fixed it when I got home.

SO....never rule out a Ground issue....we have advised folks to clean and reestablish the GROUND and solved a LOT of problems.  Folks have also had perfectly GOOD looking crimped terminals....no corrossion, but an internal issue....they cut off the end....crimped a new one on....and never an issue.  Very frustrating and very intermittent....wiggle and such and check...

Good Luck. 

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First

You did not offend me at all.  Your concerns are valid, i was happy to answer your good questions with the right answers.  As much as some try to make us believe that lithium are drop in replacements.....they arent!!!!  

Anyway, your gut feeling was spot on and after 1 week of pulling out my hair.......I FOUND THE ISSUE and its a doozie.  

The lug going into the rear box from the house battery was loose and the cable was NOT connected into the back box.  ugh......argh......sigh.....yay!!!!

4 hours ago, Tom Cherry said:

Bummer, but you did all the right things, which some have NOT, when going to Lithium.  Please don't take my comment as "talking down"....we have had this issue and folks just popped in Lithiums and went on....

OK....  In your prints and from the Magnum Manual, there is a 400  Amp Fuse.  It LOOKS Square or Rectangular.  The Monaco Prints, which I downloaded are clear and legibile.  but the outlines of the buss connectors and such on the main board are hard to follow on the prints. I THINK that the fuse would be on the main board....  About mid way into the prints there is DR3 3801004 (Schematic High Current Low Voltage).  That is the block outline.  From THAT drawing, it LOOKS like your fuse may be on the UNSWITCHED side of the Disconnect switch.  But there are subsequent drawing for different banks and also for multiple inverters (these prints were for Dynasty and all higher models).  SO, my advice....look at the one I found first and then start chasing cables.  Whether it is one the Switched side or a HOT direct connection, you need to find it and see if it is OK. 

Past that, you have, I think, reached the same conclusion.  The Inverter is somehow disconnected from the Battery Bank and when you actually Jumper the connections....the Chassis Battery is what the Inverter is seeing and all is well.  NEVER trust a Monaco Cable. The advice of the experts is to do a Voltage Measurement across each connection....that means you have to use a Jumper to get back to the "back" sometimes.  If you measure the terminal (batter connector) using the VOLT setting UNDER LOAD, then you can see the drop.....there should be barely 0.03 (3 hundredths) drop....I suspect....and that is pure GUT feel, that you have a bad battery cable terminal.  By Battery Cable, I mean any 4/0 or 2/0 high current cable from the Battery Bank to ALL the downstream connections until it gets to the inverter.

ONE REALLY OFF THE WALL comment.  IF you have a BAD Battery GROUND from the House to the Chassis Stud, then that could be the issue.  Easy enough to test or almost as easy to FIX.  If you run your Jumper from the House Ground to the Chassis Ground....and the Inverter works....then do to the HOUSE GROUND Stud....or follow it.  I had a LOW voltage Low current draw up front that would not crank the genny.  It was the House Ground Stud connection.  I loosened and cleaned and such.  BINGO....no issues in over 10 years.  I found that if I Firmly SHUT the house battery tray it would not crank.  BUT, if I moved it and then PUSHED on it, it worked.  I measured the resistance between a GOOD ground (on the Chassis) and the House Ground or negative.  I had a few ohms.  BUT, the same measurement on the Chassis....was ZERO.  I got it to stabilize....and fixed it when I got home.

SO....never rule out a Ground issue....we have advised folks to clean and reestablish the GROUND and solved a LOT of problems.  Folks have also had perfectly GOOD looking crimped terminals....no corrossion, but an internal issue....they cut off the end....crimped a new one on....and never an issue.  Very frustrating and very intermittent....wiggle and such and check...

Good Luck. 

 

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1 hour ago, limycenter said:

First

You did not offend me at all.  Your concerns are valid, i was happy to answer your good questions with the right answers.  As much as some try to make us believe that lithium are drop in replacements.....they arent!!!!  

Anyway, your gut feeling was spot on and after 1 week of pulling out my hair.......I FOUND THE ISSUE and its a doozie.  

The lug going into the rear box from the house battery was loose and the cable was NOT connected into the back box.  ugh......argh......sigh.....yay!!!!

 

Well, sometimes it doesn't take a rocket scientist to do measurements and such....and you look at the basics.  I WOULD suggest that you DO check the Ground Studs in the back and the one up front. The ones in the back make the CONTACT to the Chassis and they DO get internally corroded and will have resistance.  Simply loosening the nuts and then, with a little tension still on them, you rotate them from side to side. OR you can pull them off and clean.  There is probably TWO up front. One may go to the DASH ground and the OTHER is the Hydraulic pump and Genny Ground.  BOTH can be costly if you have a voltage drop....I KNOW THIS....just don't ask how.  LOL.

If you ever have an issue with your Genny starting, then checking the studs on the back is also a good idea. BUT, be aware. These are Copper or Bronze. Don't me Superman and torque them like a wheel nut. Someone told me that they DID that and broke one off. After 4 hours of disassembly and ordering a new stud,, all was well.

Great NEWS....

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