ABS Comm Failure - Low Battery Warning

[LakeBob]

Getting ready to leave, of course, and had the above warning come on the dash. Lost all chassis light functions, turn, brake, tail etc.  Stopped and shut off batteries to reset and it went away, then came back.  The ABS and traction control lights came on prior to the failure warning.   
 

I’m also getting a low battery warning on the house batteries.  
 

The alternator was showing 13.7 before the warming.   
 

Im grabbing my meter and starting to investigate, meanwhile anyone have any ideas? 
 

it’s a Kongsberg system

  thanks! 
bob

[Frank McElroy]

11 minutes ago, LakeBob said:

Getting ready to leave, of course, and had the above warning come on the dash. Lost all chassis light functions, turn, brake, tail etc.  Stopped and shut off batteries to reset and it went away, then came back.  The ABS and traction control lights came on prior to the failure warning.   
 

I’m also getting a low battery warning on the house batteries.  
 

The alternator was showing 13.7 before the warming.   
 

Im grabbing my meter and starting to investigate, meanwhile anyone have any ideas? 
 

it’s a Kongsberg system

  thanks! 
bob

On your coach, all the dash switches are powered by the house batteries.  Most likely you are having an issue with your big boy.  Try running the generator and then start the engine.  With the generator still running, see if your problems disappear.  If all seems to be working, clean big boy or just jumper across the two battery lugs on big boy.

[LakeBob]

Thanks Frank, I pulled and cleaned the Big boy last year.  It was not dirty or corroded at all.  

i started the coach after letting it sit with the batteries switch off and no warning lights or message appeared.   However it had cleared previously and then reappeared after driving for 3 or 4 minutes.  I have not driven it again yet.  
 

There was also a light rain while driving to get the battery this morning. 
 

[Frank McElroy]

7 minutes ago, LakeBob said:

Thanks Frank, I pulled and cleaned the Big boy last year.  It was not dirty or corroded at all.  

i started the coach after letting it sit with the batteries switch off and no warning lights or message appeared.   However it had cleared previously and then reappeared after driving for 3 or 4 minutes.  I have not driven it again yet.  
 

There was also a light rain while driving to get the battery this morning. 
 

The most important thing to know is the house battery voltage with the engine running.  On a Kongsberg chassis multiplex coach, BOTH house AND chassis batteries MUST be charging with the engine running.  If you find that the house batteries aren't charging, run the generator or bypass bigboy.  Just because big boy is clean doesn't mean it is energized.

[Tom Cherry]

50 minutes ago, Frank McElroy said:

The most important thing to know is the house battery voltage with the engine running.  On a Kongsberg chassis multiplex coach, BOTH house AND chassis batteries MUST be charging with the engine running.  If you find that the house batteries aren't charging, run the generator or bypass bigboy.  Just because big boy is clean doesn't mean it is energized.

Since Frank has tutored me….check both sides of the big boy to ground.  If it is working, then the voltages should be the same.  On your MH, it uses the proprietary Intellitec board.  It should be humming and hot enough to the touch that you cannot grab the can and leave your hand there. Then, use the volt scale and test terminal to terminal.  If it is hot and humming, then there should be, at a max, 0.1 -0.15 VDC “potential” across the terminals.  Greater than that….time to reclean again….

[LakeBob]

Thanks guys, I believe the ultimate cause was the low state of charge of the house batteries.  Based on the warning I was getting on the Magnum screen, “Low Battery- 10.2v “ and the broken terminal, and the inability of the alternator to charge the house batteries.  
 

I connected to 50 amp and monitored as the house batteries went through the bulk, absorption,  and float phases. 
 

Disconnected 50 Amp and started Coach, no issues.  I’ll take it for a short drive tomorrow to see how it behaves on the road with alternator power. 

[Frank McElroy]

When driving a Kongsberg Chassis multiplex coach always keep a close eye on the house batteries to be sure they are being charged.  If house batteries aren't being charged, it's only a matter of time before you'll be on the side of the road.  If you ever notice the house batteries not being charged, run the generator so the inverter can charge the house batteries.

[Tom Cherry]

2 hours ago, Frank McElroy said:

When driving a Kongsberg Chassis multiplex coach always keep a close eye on the house batteries to be sure they are being charged.  If house batteries aren't being charged, it's only a matter of time before you'll be on the side of the road.  If you ever notice the house batteries not being charged, run the generator so the inverter can charge the house batteries.

Followup….  There have been issues with the Intellitec board that drives or controls the Big Boy.  One solution, for the Kongsberg chassis, as Frank points out.  An emergency “Big Boy” bypass.  A simple Blue Seas 300 A switch and two short cables 4/0 wire size, with the appropriate terminal hole or diameter, would be all you needed.  Mount the Blue Seas on a small board and run both cables from the switch to the Big Boy.  I know the Dynasty is a bit “space challenged….so trace back each cable and attach there.  The other ootion….use a jumper cable between the positives as you drive.

Just a little food for thought.

[Frank McElroy]

15 hours ago, Frank McElroy said:

When driving a Kongsberg Chassis multiplex coach always keep a close eye on the house batteries to be sure they are being charged.  If house batteries aren't being charged, it's only a matter of time before you'll be on the side of the road.  If you ever notice the house batteries not being charged, run the generator so the inverter can charge the house batteries.

If you want to bypass big boy, this is how I did it with a piece of copper to jumper across the two battery studs and I unplugged the connector from RRB board #6 feeding the big boy solenoid.  I used tin snips to cut a piece of copper water pipe tubing to size.  Flattened it and drilled two holes.  A cheap effective solution to bypass big boy.   This is my setup for long term storage.

If I had a Kongsberg CCM multiplex coach, big boy would always be bypassed.  These coaches were really not designed for dry camping.  They were designed to be always on shore or generator power when not being driven.

Your other option is to replace big boy with a Blue Sea ML-ACR.

[Tom Cherry]

9 hours ago, Frank McElroy said:

If you want to bypass big boy, this is how I did it with a piece of copper to jumper across the two battery studs and I unplugged the connector from RRB board #6 feeding the big boy solenoid.  I used tin snips to cut a piece of copper water pipe tubing to size.  Flattened it and drilled two holes.  A cheap effective solution to bypass big boy. 

If I had a Kongsberg CCM multiplex coach, big boy would always be bypassed.  These coaches were really not designed for dry camping.  They were designed to be always on shore or generator power when not being driven.

Your other option is to replace big boy with a Blue Sea ML-ACR.

Thus endth today’s reading….of the Gospel according to St. McElroy.  NOW you know what the CCM Guru would do, should he own such a MH….

Thanks for sharing….  BTW, I now bypass my Big Boy for prolonged storage….

[grizzly]

Great info on this

[LakeBob]

Checked the battery connections and allowed the house bank to fully charge overnight.   Took the coach out for a 30 minute drive and no issues.  House batteries hovered around 12.2 volts for the drive.  

I am seeing a .9V differential across the Big Boy.  I'll pull it and inspect in the next couple days.   I have a shunt prepared to install (thanks @Frank McElroy!) 

Have a 5 hour drive tomorrow for a longer test drive.  

[Frank McElroy]

1 hour ago, LakeBob said:

Checked the battery connections and allowed the house bank to fully charge overnight.   Took the coach out for a 30 minute drive and no issues.  House batteries hovered around 12.2 volts for the drive.  

I am seeing a .9V differential across the Big Boy.  I'll pull it and inspect in the next couple days.   I have a shunt prepared to install (thanks @Frank McElroy!) 

Have a 5 hour drive tomorrow for a longer test drive.  

Yep, as suspected, big boy is not working properly. It could be the big boy contacts or if the big boy is not hot to the touch a control board or battery disconnect sensing wire issue.  I've now repaired a few defective board on your era coach. 

An easy alternative solution is to just run the generator and let the Magnum charge the house batteries.  There is no issue in running the generator while driving.

[Tom Cherry]

5 minutes ago, Frank McElroy said:

Yep, as suspected, big boy is not working properly. It could be the big boy contacts or if the big boy is not hot to the touch a control board or battery disconnect sensing wire issue.  I've now repaired a few defective board on your era coach. 

An easy alternative solution is to just run the generator and let the Magnum charge the house batteries.  There is no issue in running the generator while driving.

Nor is there any issue with a jumper cable between the positives.  The question is….did you measure the voltage, as requested, between each terminal and ground.  Next question…was the Big Boy hot and humming?  If not hot & not humming….the control board is probably shot.  I agree with Frank.  Jumper the terminals or use jumper cable.  The board failure is a known issue.  Answer the above….then, you will know whether to clean (may be totally wasted) or jumper because the control board is shot.

Let us know….

[LakeBob]

Tom, the differential was measured as you indicated, from each terminal to ground.  I forgot to feel the big boy, not sure if it was hot and could not hear any humming. I'll do that at the next stop.  

If it acts up again, I'll run the generator to keep the batteries charged.   We've run the generator while driving in hot weather in the past to run the roof AC's. 

[Dr4Film]

Time to remove the Big Boy then install the Blue Seas ML-ACR device. It is a lot smarter than that dumb Big Boy plus it won't be hot when you touch it. Don't like electrical stuff being that hot at the rear of my engine in the rear electrical run bay.

[Tom Cherry]

9 hours ago, LakeBob said:

Tom, the differential was measured as you indicated, from each terminal to ground.  I forgot to feel the big boy, not sure if it was hot and could not hear any humming. I'll do that at the next stop.  

If it acts up again, I'll run the generator to keep the batteries charged.   We've run the generator while driving in hot weather in the past to run the roof AC's. 

When you posted “differential”, I assumed that was measured across the terminals as requested.  Bottom line.  No HUM. No TOO HOT TO HOLD….It ain’t working. Odds are, based on way too many posts and testing here, your Intellitec board has failed.  This board also controls the function or ability to use or have a boost switch.  Occasionally we see a Big Boy coil failure, but 80 or maybe 90% of the time, the failure is in the contracts.  It’s BROKE.

The final test.  Put your hand on it.  Cool?  Bad!  But then have someone turn on the ignition.  Put your hand on the Big Boy.  Have them hold on the BOOST SWITCH.  If you don’t feel it engage or click, then the Boost function in the board is dead.  If it comes on….then check voltage to ground on each side….should be the same. Then…IMPORTANT…put your VOM on the terminals.  If there is almost ZERO volts, then the contacts are clean.

These tests, assuming you want to know the problem, are necessary.

Personally, I would not spend time and money on this.  Install Frank’s “poor man’s” solid jumper.  Sort of foolish to have to run your genny to keep the house charged….the Intellitec board and Big Boy should do that.

Richard makes a good point…but since you have the CCM, as we have said and Frank recommends, the Blue Seas ML-ACR is worthless.  All it does for you, if one bank has a massive drain, it keeps the other bank from being sucked down.  Easy to install.  Don’t bother to get the one with the fancy remote…PITA to run a 4 bundle wire loom to the front.  Need BOOST.  Walk back and push button for MANUAL.  Then, after or when boost is not needed….push button to AUTO.  Now You have. BIRD charging again.

Simple as that….