2003 Sig may not be charging HOUSE from alternator. Help please.

[Gene Y]

Not sure of charging sequence. Batteries will charge when on shore power, both chassis and house. 

Does that charging sequence go thru the Big Boy?

If so,  does that indicate that the Charging system is operating properly. 

With engine running the batteries are not charging, suspect I need to check for output from the alternator. Replaced it last year with Neville Lucce (spelling wrong)type alternator. Had been working perfectly on long 2 month trip until 2 weeks ago. 

Could someone provide a step by step on checking the charging system. 

Thanks 

[Ivan K]

Can you post a pic of your rear run board? Do you have the big finned isolator? If so, there is different path for each charging source and the alternator must be of the same type as original.

[Gene Y]

Don't see a finned isolator . Here is pic , thanks. 

Forgot to mention, currently on shore power. Can hear the BB humming. 

[Ivan K]

Thanks for the pic, totally different from mine but someone else will step in soon, I'd bet.

[timaz996]

8 minutes ago, Ivan K said:

Thanks for the pic, totally different from mine but someone else will step in soon, I'd bet.

It sure seems that Monaco didn't standardize anything. 

[Frank Bergamo]

Gene,

Yes, the charging system goes through the Big Boy. On mine, the left big terminal on the bottom of the Big Boy comes from the alternator chassis side. The right big terminal comes from shore/generator house side. When working properly, both big terminals should have the same voltage on each side. Check voltage on positive terminal on back of alternator or at chassis batteries. Should be 13.8-14 volts if charging. Hope this helps.

[Ivylog]

I would check the voltage on the left lug of the BigBoy and then start the engine and retest. The voltage should increase by more than 1 volt… ideally closer to 14. If no change then the alternator is suspect but make sure the regulator on it is getting 12+ volts before deciding it’s bad.

Once the voltage gets above 13.3, the BIRD will energize the Big Boy and tie both battery banks together.

[Tom Cherry]

1 hour ago, Gene Y said:

Don't see a finned isolator . Here is pic , thanks. 

Forgot to mention, currently on shore power. Can hear the BB humming. 

OK....from the TOP.  Here is what I think or have a pretty confident IDEA is going on.  First some tests..

Shore OFF  Engine OFF.  If someone can turn off or trip the breaker at the pedestal and you stand back where the BIg Boy (yes...it is a REAL Big Boy), then it should go CLUNK or drop out pretty quickly.  HOPE it does.  OK...turn on your headlights for maybe 10 minutes or so...without being on shore and NO ENGINE running.  This takes off a bit of the charge....DON'T worry...a simple Jumper cable between the two banks (positive only) will get it restarted...should the chassis be that low.

OK....start the engine after the headlights were off.  In a few minutes, you should hear the Big Boy go CLUNK.  and it, in both cases, will HUM.  The Hum is the fact that the control board (R6 on some...would have to look at your prints) is sending out a pulsed signal.  The board sends out maybe 20 to 50 pulse of PURE 12 VDC per SECOND.  OK....do the math..  Lets say 20 pulses.  That is a pulse DURATION (ON and OFF and back ON again) of 50 Milliseconds (1000 divided by 20).  SO, then the ON portion of the Pulse will be around 32 Milliseconds...or 2/3's of the total Pulse.  If you put a VOM on the terminals (small ones) on the Big Boy, it would read around 8 Volts.  EIGHT (8) is 2/3rds of 12 VDC.  So, in effect, your VOM is averaging the voltage and will measure (roughly) 8 Volts.  

NOW...WHY.  The Big Boy is NOT rated for continuous 12 VDC current....held on (as in holding on the BOOST switch), you will burn up the coil in maybe a few minutes.  YES, some don't understand and have actually fried the Big Boy with the old golf T wedged trick.  That works for OLDER solenoids that were 100% 12 RATED or Continuous Duty...NOPE the BIG BOY ain't.  9 Volts is the limit.  My Camelot system uses a different controller and it only puts out an average of a little over 3 Volts and it works fine.  It actually RUNS cooler (not as hot to the touch) and is quitter.  SO...you hear HUMMING on Shore.  GREAT.  Now you should hear HUMMING when the Engine is running.  NO HUM...no CHARGE the House from the Alternator.  

OK...what if NO HUM.  Only ONE thing, most likely, has happened.  Someone, unknowingly, replaced the Chassis Battery cut off switch with the WRONG one.  BOTH your Cut Off switches must have TWO big studs and two little terminals.  if you see wires behind the switch not hooked up...odds are, if you connect them, it will Hum.  The Humming from the Shore tells me the Board is getting power and the house switch is a 4 "terminal" switch and is correct.  Don't take that for granted...LOOK.

OK...If you have HUM....then you need to go forward.  First....with nothing ON and NO shore...no engine...measure on either side of the Big Boy.  Measure to GROUND.  That should be around 12.5 VDC...assuming all batteries are charged.  NOW...  flip on the pedestal.  CLUNK goes the Big Boy....and it starts to HUM and gets hot (you can NOT hold your hand on it unless all the nerve endings are dead.  It IS supposed to be that hot).  NOW, repeat your measurement.  The House will probably be in the 13's or maybe upper 13's.  Whatever the Inverter Remote is showing...you should see that...maybe no more than 2/10 (0.20 VDC) difference.  IF one side is still showing 12.5 or so...then that has to be the CHASSIS and the Big Boy's contacts are bad.  There is a HOW TO in the Files....on how to disassemble and clean it.  Folks that can't install an air filter in a modern car have easily pulled it apart and cleaned the contacts.  Frank McElroy wrote a great article.

NOW...if the Big Boy ain't working or Humming when the engine is running (and NO SHORE), then final test.  Have someone on hand that can push the Boost Button.  The Big Boy should go CLUNK.  The Chassis side will show the increased voltage from the alternator...in the high 13's....but it might take a few minutes for the intake heaters to shut off...so measure maybe 3 minutes or even 5.  THEN the full charging voltage.  NOW...measure the OTHER side again.  Should be LOW...maybe in the 12's or lower.  Have someone PUSH the BOOST...measure the voltage....it should NOT change on the Chassis but the House should show the same voltage.  BOTH voltages should be within 0.05 (5 Hundredths) of a volt...otherwise the contacts are pitted and corroded and need to be cleaned.

IF the board does NOT work and the BIg Boy ain't humming when the engine is running....PROBLEM.  NOW, what you SHOULD DO...is to have a LOAD on the house...so tell the person to stop (let off on the Boost).  Then turn on all the interior lights and run the ceiling fans....that will then need to have the HOUSE recharged...and the inverter does NOT have power.

Then push BOOST...then you should have same voltage.  UNTIL you run the tests....we can't help you as you need to do the step by step troubleshooting...so do it and post...

[Gene Y]

1 hour ago, Frank Bergamo said:

Gene,

Yes, the charging system goes through the Big Boy. On mine, the left big terminal on the bottom of the Big Boy comes from the alternator chassis side. The right big terminal comes from shore/generator house side. When working properly, both big terminals should have the same voltage on each side. Check voltage on positive terminal on back of alternator or at chassis batteries. Should be 13.8-14 volts if charging. Hope this helps.

Thanks I will check this out today. 

15 minutes ago, Ivylog said:

I would check the voltage on the left lug of the BigBoy and then start the engine and retest. The voltage should increase by more than 1 volt… ideally closer to 14. If no change then the alternator is suspect but make sure the regulator on it is getting 12+ volts before deciding it’s bad.

Once the voltage gets above 13.3, the BIRD will energize the Big Boy and tie both battery banks together.

Something I will try tomorrow as we will be moving from 1 campsite to another then. 

Thanks 

14 minutes ago, Tom Cherry said:

OK....from the TOP.  Here is what I think or have a pretty confident IDEA is going on.  First some tests..

Shore OFF  Engine OFF.  If someone can turn off or trip the breaker at the pedestal and you stand back where the BIg Boy (yes...it is a REAL Big Boy), then it should go CLUNK or drop out pretty quickly.  HOPE it does.  OK...turn on your headlights for maybe 10 minutes or so...without being on shore and NO ENGINE running.  This takes off a bit of the charge....DON'T worry...a simple Jumper cable between the two banks (positive only) will get it restarted...should the chassis be that low.

OK....start the engine after the headlights were off.  In a few minutes, you should hear the Big Boy go CLUNK.  and it, in both cases, will HUM.  The Hum is the fact that the control board (R6 on some...would have to look at your prints) is sending out a pulsed signal.  The board sends out maybe 20 to 50 pulse of PURE 12 VDC per SECOND.  OK....do the math..  Lets say 20 pulses.  That is a pulse DURATION (ON and OFF and back ON again) of 50 Milliseconds (1000 divided by 20).  SO, then the ON portion of the Pulse will be around 32 Milliseconds...or 2/3's of the total Pulse.  If you put a VOM on the terminals (small ones) on the Big Boy, it would read around 8 Volts.  EIGHT (8) is 2/3rds of 12 VDC.  So, in effect, your VOM is averaging the voltage and will measure (roughly) 8 Volts.  

NOW...WHY.  The Big Boy is NOT rated for continuous 12 VDC current....held on (as in holding on the BOOST switch), you will burn up the coil in maybe a few minutes.  YES, some don't understand and have actually fried the Big Boy with the old golf T wedged trick.  That works for OLDER solenoids that were 100% 12 RATED or Continuous Duty...NOPE the BIG BOY ain't.  9 Volts is the limit.  My Camelot system uses a different controller and it only puts out an average of a little over 3 Volts and it works fine.  It actually RUNS cooler (not as hot to the touch) and is quitter.  SO...you hear HUMMING on Shore.  GREAT.  Now you should hear HUMMING when the Engine is running.  NO HUM...no CHARGE the House from the Alternator.  

OK...what if NO HUM.  Only ONE thing, most likely, has happened.  Someone, unknowingly, replaced the Chassis Battery cut off switch with the WRONG one.  BOTH your Cut Off switches must have TWO big studs and two little terminals.  if you see wires behind the switch not hooked up...odds are, if you connect them, it will Hum.  The Humming from the Shore tells me the Board is getting power and the house switch is a 4 "terminal" switch and is correct.  Don't take that for granted...LOOK.

OK...If you have HUM....then you need to go forward.  First....with nothing ON and NO shore...no engine...measure on either side of the Big Boy.  Measure to GROUND.  That should be around 12.5 VDC...assuming all batteries are charged.  NOW...  flip on the pedestal.  CLUNK goes the Big Boy....and it starts to HUM and gets hot (you can NOT hold your hand on it unless all the nerve endings are dead.  It IS supposed to be that hot).  NOW, repeat your measurement.  The House will probably be in the 13's or maybe upper 13's.  Whatever the Inverter Remote is showing...you should see that...maybe no more than 2/10 (0.20 VDC) difference.  IF one side is still showing 12.5 or so...then that has to be the CHASSIS and the Big Boy's contacts are bad.  There is a HOW TO in the Files....on how to disassemble and clean it.  Folks that can't install an air filter in a modern car have easily pulled it apart and cleaned the contacts.  Frank McElroy wrote a great article.

NOW...if the Big Boy ain't working or Humming when the engine is running (and NO SHORE), then final test.  Have someone on hand that can push the Boost Button.  The Big Boy should go CLUNK.  The Chassis side will show the increased voltage from the alternator...in the high 13's....but it might take a few minutes for the intake heaters to shut off...so measure maybe 3 minutes or even 5.  THEN the full charging voltage.  NOW...measure the OTHER side again.  Should be LOW...maybe in the 12's or lower.  Have someone PUSH the BOOST...measure the voltage....it should NOT change on the Chassis but the House should show the same voltage.  BOTH voltages should be within 0.05 (5 Hundredths) of a volt...otherwise the contacts are pitted and corroded and need to be cleaned.

IF the board does NOT work and the BIg Boy ain't humming when the engine is running....PROBLEM.  NOW, what you SHOULD DO...is to have a LOAD on the house...so tell the person to stop (let off on the Boost).  Then turn on all the interior lights and run the ceiling fans....that will then need to have the HOUSE recharged...and the inverter does NOT have power.

Then push BOOST...then you should have same voltage.  UNTIL you run the tests....we can't help you as you need to do the step by step troubleshooting...so do it and post...

Something that will probably need to wait until we get home. Still 10 days away. This is the step by step I was looking for. One issue may be the listening for the hum with the engine running. Engine exhaust is straight piped and is rather loud. Big Boy is directly above it. I read Frank's step by step on cleaning the contacts and am prepared to do that when we return home. I think my confusion comes from whether the batteries are able to be charged while on shore power if the Big Boy is corrupted.