On shore power & dead cassis batteries/no start w/ boost

[Newcsn]

Our 06 Dynasty has been hooked to 50 AMP shore power for 30+ days since it was lasted started - chassis batteries are less than 2 years old. Attempted to start this AM and nothing more than a couple grunts. Attempted the Battery Boost and no difference - house batteries are at 13.4v.

Where would I find a diagnostics trouble tree to figure out why the chassis batteries have gone dead?

Thanks for your assistance!

[Martinvz]

Hi Mark, the age of the chassis battery does not exempt you from either bad batteries or from not charging, as per my recent experience. 
You did not state what the chassis battery voltage is. If it is less than 12.4 V then you need to check the voltages at the Big Boy on either side. 

[Frank McElroy]

Likely you have a big boy that needs to be cleaned.  Big boy connects the chassis batteries to the house batteries so that they can be charged while on shore power with both battery disconnect switches turned ON.  What is the chassis battery voltage?

[Newcsn]

10 minutes ago, Frank McElroy said:

Likely you have a big boy that needs to be cleaned.  Big boy connects the chassis batteries to the house batteries so that they can be charged while on shore power with both battery disconnect switches turned ON.  What is the chassis battery voltage?

I checked the voltage on both sides of the Big Boy & directly on the chassis batteries. 13.3v on the house side & 11.74v on the chassis batteries & BB.

Looks like I’ll start by taking the BB off and giving it a cleaning!

[Ivylog]

4 minutes ago, Newcsn said:

I checked the voltage on both sides of the Big Boy & directly on the chassis batteries. 13.3v on the house side & 11.74v on the chassis batteries & BB.

Looks like I’ll start by taking the BB off and giving it a cleaning!

Assuming it is as hot to the touch…most likely energized but if not then you have another problem.

[Newcsn]

2 minutes ago, Ivylog said:

Assuming it is as hot to the touch…most likely energized but if not then you have another problem.

Yep - hot to the touch!

If I clean the BB & reinstall it should it then start charging the chassis batteries? Thanks

Edited March 30 by Newcsn

[Dr4Film]

I am removing the HOT Big Boy and installing the Blue Seas ML-ACR in its place. No longer have to deal with having something that hot in my Rear Run Bay (aka RRB) or not working requiring to R&R it every so often.

[96 EVO]

3 minutes ago, Dr4Film said:

I am removing the HOT Big Boy and installing the Blue Seas ML-ACR in its place. No longer have to deal with having something that hot in my Rear Run Bay (aka RRB) or not working requiring to R&R it every so often.

At the risk of jinxing myself........ Mine has never been touched! 

[Just Jim]

It was my understanding that the BB would join the two battery banks together momentarily.  Most of the coaches I've seen had to have a trickle charger to charge the chassis battery as shore power only charged the house batteries.  I've heard of people putting a tooth pick or some other type of wedge into the boost switch to keep it connected while parked to combine the battery banks and charge them both, but I never tried that.  I too have replaced with the ML-ACR.  No issues with battery charge or boosting anymore... Knock on wood!!!

Edited March 30 by Just Jim

[96 EVO]

22 minutes ago, Just Jim said:

It was my understanding that the BB would join the two battery banks together momentarily.  Most of the coaches I've seen had to have a trickle charger to charge the chassis battery as shore power only charged the house batteries.  I've heard of people putting a tooth pick or some other type of wedge into the boost switch to keep it connected while parked to combine the battery banks and charge them both, but I never tried that.  I too have replaced with the ML-ACR.  No issues with battery charge or boosting anymore... Knock on wood!!!

Late model coaches use a B.I.R.D module along with the Big Boy solenoid to charge both banks with any charging source!

[Newcsn]

2 hours ago, Frank McElroy said:

Likely you have a big boy that needs to be cleaned.  Big boy connects the chassis batteries to the house batteries so that they can be charged while on shore power with both battery disconnect switches turned ON.  What is the chassis battery voltage?

Oh my word - the contacts were one corroded up mess inside the BB!!!! No wonder it stopped charging the chassis batteries! Cleaned, reassembled & reinstalled - now we’ll see if the chassis batteries recharge!

Thanks again!!!

Now that I’ve cleaned the BB, should the Battery Boost allow me to start the coach w/ the aid of the house batteries - they’re at 13.4v? I attempted this & it still just grunts. Chassis batteries are at 11.1v. 

Edited March 30 by Newcsn

[jacwjames]

Back in 2012 the chassis battery died while my wife was driving from E TN to northern Michigan.  She was able to use the battery boost to start the coach and continued north.  I changed the chassis battery when she to to where I was. 

You should be able to start your coach with the boost button.

[Tom Cherry]

17 hours ago, Newcsn said:

Oh my word - the contacts were one corroded up mess inside the BB!!!! No wonder it stopped charging the chassis batteries! Cleaned, reassembled & reinstalled - now we’ll see if the chassis batteries recharge!

Thanks again!!!

FWIW….  You have a much different system than most. Your BIRD (BiDirectional) or two way charging is controlled by two components.  There is an Intellitec (#6….memory) board in the rear run bay.  That feeds a pulsed (NOT a constant) 12 VDC signal to the Big Boy.  If you were to measure the “voltage” between the two small terminals, using a VOM, would “APPEAR” to be around 8 VDC. In reality….it is a full 12 or maybe 13 Volts…but it is pulsing on and off.  The pulse ON is about TWICE the off time. We’re talking maybe 50 ON/OFF pulses per SECOND….so the VOM just sort of “averages it.

The Big Boy is NOT rated for 12 - 13 VDC continous to the coil…..thus the pulsing.  NOW….as long as the Big Boy is working and “humming” or making noise….then the #6 board is fine.  

BUT…your measurements were a DEAD giveaway.  After you cleaned the Big Boy, if you measured the voltage…..the reading (to groound) would be less than a tenth or maybe TWO twnths.  NOW…the verification would be to measure the two studs….you should see less than a tenth or two.  That means NO resistance. So, genesloy speaking…..You are good to go.

NOW…here is a little more background;  there is really NO practical or financial reason to replace or remove or “demo” the Board 6 and Big Boy.  You know how to clean the BB. IF you ever had an issue with the board, we have TWO high tech members…  @Frank McElroy & @pwhittle.  They are well versed.  They can diagnose and repair most if not all the up front and rear boards.  They charge about 20% (don’t make that an exact) number as a “Candy Factory”.  Most of the techs that diagnose and send boards to them report issues and astronomical price increases.  So…that is what I hear and also know….

Next up….you need to know a little more.  Frank is an expert and I learn from him or helping others.  He and I have actually bypassed or disconnected our Big Boy when in long term storage.  That shuts down the pulsed signal and there is no load on the Big Boy coil….It can be done several ways.  Frank made a Copper buss.  I added a jumper across my two banks.  You COULD use a simple automotive jumper cable.  You only need to remove one of the small control wires to “disconnect” the coil….that saves it from being on “forever”.

Next UP.  If you have an issue….and I had one….only ONE in 15 years…..the procedure is this.  Turn off both banks…..attach a Jumper cable. Turn ON the banks.  Start the Genny or plug in.  The  let the genny or the Magnum “redharge” the Chassis.  In your case….you start the genny off the Chassis.  Some off the House.  Let them charge for maybe 30 minutes….that will, if your chassis batteeis are “OK” recharge them.

NOW….the nice thing about your Intellitec system will work or run the Boost from either bank.  The lower ends like the Camelots only work off one source.  So, you always have a boost.  You CAN follow the procedure in the manual (read both sections 8 & 9) and then put a surface charge on a bank.  

All this to say….if you rip out the system and go with the ML-ACR….then it is a chore to run the wiring upfront.  Maybe not for all… but, it would not be worth it for me.  If I had a Dynasty….I doubt I would ever consider it…. if you understand and properly maintain the Big Boy….it is very versatile and robust.

EDIT….

in a subsequent post, even though Paul & Frank can fix the #6 board…..they are or will probably will replace  the BB with the ML-ACR.  However, if they want full “Boost remote capabilities”, then that will requite finding the “elusive Monaco” spare conduit and spare wires or running a small 4 or 5 wire harness from the rear to the Front.I don’t recall  any Dynasty owners that have done that…..but who knows. 

END OF EDIT

However, the fact still remains that most that install the Blue Seas ML-ACR do not have a first class system (OEM Monaco Intellitec & BB) like you do and the majority are lower food chain and it IS an upgrade for them.

Now you know…..the rest  of the story…

 

16 hours ago, jacwjames said:

Back in 2012 the chassis battery died while my wife was driving from E TN to northern Michigan.  She was able to use the battery boost to start the coach and continued north.  I changed the chassis battery when she to to where I was. 

You should be able to start your coach with the boost button.

His Big Boy was corroded.  He had almost a 2 Volt drop.  That would severely reduce the amps…

[cbr046]

52 minutes ago, Newcsn said:

Now that I’ve cleaned the BB, should the Battery Boost allow me to start the coach w/ the aid of the house batteries - they’re at 13.4v? I attempted this & it still just grunts. Chassis batteries are at 11.1v. 

Are you holding the battery boost switch for a minute or more?  What you're doing is 'fast charging' the chassis batts, not the same as jumper cable aproach. 

Your coach may be different, but this is from 2003 Endeavor Owners -

Quote

hold down the Auxiliary Start switch for one minute. Release the switch
for one minute, then engage the switch for one minute. Alternate this cycle
3-5 times. This will avoid overheating the Boost solenoid.
• Next, hold the switch down for one minute and turn the key on. The
battery voltage gauge on the dash should indicate at least 12 Volts. If
voltage is sufficient with the Auxiliary Start switch held down, try starting
the engine.

Good luck,

- bob

[Tom Cherry]

30 minutes ago, cbr046 said:

Are you holding the battery boost switch for a minute or more?  What you're doing is 'fast charging' the chassis batts, not the same as jumper cable aproach. 

Your coach may be different, but this is from 2003 Endeavor Owners -

Good luck,

- bob

Back to basics.  First.  His system is slightly different from yours.  You only have power for the boost from either the House (most likely) or Chassis.  MOST House starts the Genny system power the Big Boy from that side.

BUT he has the Intellitec board #6.  It will work from either.  If the House on yours is down….then trying to boost the Genny ain’t gonna work…no juice to power the boost solenoid.

However…more importantly…which was posted….his Boost/Big Boy was corroded and had a high, very high, resistance on the contacts.  So, holding it in….with a 2 or more NO LOAD Voltage drop….ain’t gonna get much if any JUICE or amperage.  Now, the simple solution….a Jumper cable between the banks.  ODDS ARE, the Chassis was NOT drained to dead….so, running the genny or letting the Magnum charge BOTH (via the Jumper) for 30 minutes or so….would have restored the chassis.  BUT the BB needed (and was) cleaned…

[Frank McElroy]

40 minutes ago, Tom Cherry said:

FWIW….  You have a much different system than most. Your BIRD (BiDirectional) or two way charging is controlled by two components.  There is an Intellitec (#6….memory) board in the rear run bay.  That feeds a pulsed (NOT a constant) 12 VDC signal to the Big Boy.  If you were to measure the “voltage” between the two small terminals, using a VOM, would “APPEAR” to be around 8 VDC. In reality….it is a full 12 or maybe 13 Volts…but it is pulsing on and off.  The pulse ON is about TWICE the off time. We’re talking maybe 50 ON/OFF pulses per SECOND….so the VOM just sort of “averages it.

The Big Boy is NOT rated for 12 - 13 VDC continous to the coil…..thus the pulsing.  NOW….as long as the Big Boy is working and “humming” or making noise….then the #6 board is fine.  

BUT…your measurements were a DEAD giveaway.  After you cleaned the Big Boy, if you measured the voltage…..the reading (to groound) would be less than a tenth or maybe TWO twnths.  NOW…the verification would be to measure the two studs….you should see less than a tenth or two.  That means NO resistance. So, genesloy speaking…..You are good to go.

NOW…here is a little more background;  there is really NO practical or financial reason to replace or remove or “demo” the Board 6 and Big Boy.  You know how to clean the BB. IF you ever had an issue with the board, we have TWO high tech members…  @Frank McElroy & @pwhittle.  They are well versed.  They can diagnose and repair most if not all the up front and rear boards.  They charge about 20% (don’t make that an exact) number as a “Candy Factory”.  Most of the techs that diagnose and send boards to them report issues and astronomical price increases.  So…that is what I hear and also know….

Next up….you need to know a little more.  Frank is an expert and I learn from him or helping others.  He and I have actually bypassed or disconnected our Big Boy when in long term storage.  That shuts down the pulsed signal and there is no load on the Big Boy coil….It can be done several ways.  Frank made a Copper buss.  I added a jumper across my two banks.  You COULD use a simple automotive jumper cable.  You only need to remove one of the small control wires to “disconnect” the coil….that saves it from being on “forever”.

Next UP.  If you have an issue….and I had one….only ONE in 15 years…..the procedure is this.  Turn off both banks…..attach a Jumper cable. Turn ON the banks.  Start the Genny or plug in.  The  let the genny or the Magnum “redharge” the Chassis.  In your case….you start the genny off the Chassis.  Some off the House.  Let them charge for maybe 30 minutes….that will, if your chassis batteeis are “OK” recharge them.

NOW….the nice thing about your Intellitec system will work or run the Boost from either bank.  The lower ends like the Camelots only work off one source.  So, you always have a boost.  You CAN follow the procedure in the manual (read both sections 8 & 9) and then put a surface charge on a bank.  

All this to say….if you rip out the system and go with the ML-ACR….then it is a chore to run the wiring upfront.  Maybe not for all… but, it would not be worth it for me.  If I had a Dynasty….I doubt I would ever consider it…. if you understand and properly maintain the Big Boy….it is very versatile and robust.  I don’t recall  any Dynasty owners that have done that…..but who knows.  most that install the Blue Seas ML-ACR do not have a first class system like you do and are lower food chain and it IS an upgrade for them.

Now you know…..the rest  of the story…

 

His Big Boy was corroded.  He had almost a 2 Volt drop.  That would severely reduce the amps…

Attached is a picture of my test jig after repairing the big boy and salesman switch circuit board PCB#6 with big boy connected and the pulsed output going to big boy connected to the scope. 

One side of the big boy coil is fed by a constant 12 volts and the other side is pulsed from 12 VDC to ground for about 2/3 the time.  This gives an average of 8 VDC across the big boy.  Strong enough to keep it engaged but to too strong to burn up the coil.  The pulsing signal is what causes the hum. 

When you press the battery boost switch, it holds the pulsed ground signal to a constant ground and the hum goes away.  If you hold the battery boost for more than about ten minutes, you run the risk of burning up the coil.  But, in most cases, when you need the battery boost, the coil would likely start by being cold.

That's how it works.

[Frank McElroy]

BTW, one trick to try while connected to shore power and big boy is engaged (hot) but current is not flowing through it is to cycle the chassis battery disconnect switch such that big boy disengages and re-engages.   More likely than not, you will get an internal contact good enough to get by until you have time to clean it.  Over the years, this trick has helped a number for folks get back on the road.

[MyronTruex]

Just because you cleaned the contacts does not mean it is actually working, (well). Your engine batteries could be in very bad shape internally and you should give the big boy at least four hours to try to bring them up from the dead. 

Putting a voltmeter across the engine batteries while cranking will tell the story. 

If you can get a jumper cable and bypass the big boy by connecting both battery banks this should help as well. I don't mean the wimpy ones you use to start a car. Get one that is solidly built.

 

[jacwjames]

3 hours ago, Tom Cherry said:

His Big Boy was corroded.  He had almost a 2 Volt drop.  That would severely reduce the amps…

I may have read it wrong but it sounded like he rebuilt the BB but the chassis battery was dead. 

[96 EVO]

2 hours ago, Frank McElroy said:

BTW, one trick to try while connected to shore power and big boy is engaged (hot) but current is not flowing through it is to cycle the chassis battery disconnect switch such that big boy disengages and re-engages.   More likely than not, you will get an internal contact good enough to get by until you have time to clean it.  Over the years, this trick has helped a number for folks get back on the road.

Frank, any advantage to doing this occasionally on an operational BB, when your plugged into shore power for an extended period?

[Frank McElroy]

35 minutes ago, 96 EVO said:

Frank, any advantage to doing this occasionally on an operational BB, when your plugged into shore power for an extended period?

I don't see much of an advantage in periodically cycling the big boy but if you do be sure to do it under little if any load.

When I'm camping, every few days I'll check the chassis battery voltage to be sure big boy is working and the chassis batteries are being charged.  When driving, I'll keep an eye on the house battery voltage to be sure the engine alternator is charging them through big boy.

When in storage and plugged in, I bypass big boy with a copper strip and unplug the 8 pin connector on the side of PCB#6.  This will charge both the house and chassis batteries and shut off power to the big boy coil.  Attached are a few pictures.

[Tom Cherry]

1 hour ago, jacwjames said:

I may have read it wrong but it sounded like he rebuilt the BB but the chassis battery was dead. 

See my post(s).  What he did was not “rebuild”, but just cleaned.  He had a No Load drop of almost 2 VDC.  That be massive.  He also had allowed or it “happened” to get the Chassis batteries down to 11.4.  That is basically a pair of “DEAD BATTERIES”.  NO SENSE in trying to crank.  All that is doing is running them down more.

It will take time to get them recharged.  Typically, the Magnum puts out 100 (max) amps in BULK.  Depending on how low the House may be….they will “share”.

I know from experience that it takes 3 hours or so to get my House back up from around 12 to 12.7.  So….it ain’t gonna happen quickly.

BUT….add in this.  I also know that when I had a NO START….only happened one time….due to a Big Boy or BIRD Module failure….I cranked the Genny.  I jumpered the House to the Chassis with a single Jumper….medium size…maybe #1.  I started the Genny.  Let it run for maybe 15 minutes…..then cranked the engine with ease.  I let it run for maybe 30 minutes more….while I drove to a nearby Interstate distributor and picked up two new Chassis.  Never bothered to measure….irrelevant.  The Magnum and BIRD were working.

When I came back…..genny had been charging for maybe 45 minutes.  The engine had run for 30 minutes.  I figure the 160 A alternator was pumping maybe 125 or so….so I had a total of 225 amps.  I shut down engine.  Pulled the jumper cable.  BINGO, Engine fired instantly.  Those batteries were 5 years old.

IF he has 2 year or new batteries…..I think all will be well.  Best way to charge…..start Genny.  Drive that sucker.  He has a 200 A LN alternator.  50 miles….I’ll bet the batteries will start without any issues.

MY ADVICE …..charge…drive if you can.  Let shore and Magnum charge for a day or so.  I think the Chassis will be fine.  Follow Frank’s advice….the BIRD board (Intellitec #6) is working.  BB contacts cleaned.  All should be well….

[pwhittle]

I am a big fan of the ML-ACR.

We bought our 2005 Signature seven years ago now, and I had to clean the Big Boy to make it work properly. When it failed again two years later, I switched to the ML-ACR, and have not had any issue since 2019.

i did run some wires to the front for the switch, but have since found the Spare Harness that Monaco installed, so it could have been a simpler install.

I have also installed one on our 1994 Signature, and have also helped install them on three other coaches. 
 

Intellitec makes many great products. I do not consider the BigBoy and the associated control board their best work.

Paul

Edited March 31 by pwhittle

[Frank McElroy]

16 minutes ago, pwhittle said:

I am a big fan of the ML-ACR.

We bought our 2005 Signature seven years ago now, and I had to clean the Big Boy to make it work properly. When it failed again two years later, I switched to the ML-ACR, and have not had any issue since 2019.

i did run some wires to the front for the switch, but have since found the Spare Harness that Monaco installed, so it could have been a simpler install.

I have also installed one on our 1994 Signature, and have also helped install them on three other coaches. 
 

Intellitec makes many great products. I do not consider the BigBoy and the associated control board their best work.

Paul

I agree.  Actually I have a ML-ACR sitting on my work bench ready to replace my Big Boy the next time it needs cleaning.  I just need time to do it. 

I like being able to decide from the driver's seat when to engage and disengage it.  As for extra wiring, most Dynasty and above coaches have an open conduit from front to back for extra wiring if you already used the Monaco installed prewiring harness not already used in the RRB and under the dash.

[Just Jim]

Frank,  I've looked at the wiring diagrams and don't see any mention of spare wires or extra conduit?  I've purchased wire and was just fixing to run some extras, so your comment is very timely.  I've looked but have not found any.  I have two rear run boxes; one on each side.  There is so much wiring that it could be right in front of me.  Any idea what it would look like and a more specific place to check?  I've looked under the dash and don't see any spare wire.  Again, any specific location to look and what to look for?

Jim