1996 Prevost Royale Chassis battery problems

[metalaccents]

About three weeks ago I was at a campground and when it was time to leave my 1996 Prevost XL45 bus would not start.  All it would do is make a clicking noise and not turn over (note that the clicking noise was not constant and only clicked once then nothing else. it is as if the batteries do not have enough charge to turn over the engine).  Had a tech come out for jump start and he could not jump it with the two 3000 amp Noco boost jump starters.  He was not equipped well enough to have a battery teste, either.  I decided to replace all four chassis batteries and the bus started with no hesitation and has started with no issues for the last three weeks.

The last time I drove the bus about 100 miles and stayed the night in a rest stop and started the bus in the morning and ran it for about 15 minutes then drove 4 miles to the next campground and turned off the engine when in my site.  About 3 hours later I decided to start the bus to level it with some blocks and the bus would not start.  It did the same thing that happened three weeks ago before I replaced the batteries.  It simply made a click noise when I tried to start the bus and would not crank the engine (I am assuming that there is not enough voltage in the batteries to turn over the engine).  I tried starting the bus from the ignition at driver seat and from the engine bay with the same result.

Here is what I have done so far:  Used a volt meter to check the chassis batteries.  There are four 12v batteries in series and parallel making it a 24 volt system.  The voltage reads as follows in each battery; Bat 1 - 12.86v, Bat 2 - 11.35v, Bat 3 - 11.35v, and Bat 4 - 12.86v.  When ignition key is turned on there are no warning lights and all dash lights are normal and the transmission lights are normal.  I tripped and reset all breakers that I could find and pulled out and pushed back in all relays to check for corrosion and found nothing that stands out.  All four batteries are new with 2022 dates on them.  Battery cables are in good condition with the exception of the main ground wire showing its age where the wire covering is cracked in the main bend and has exposed copper wire, however, there is no sign of corrosion, just the wire covering is peeled back at the bend (I plan to replace this soon and not sure if this could cause the batteries to not charge this one time in the last three weeks).

Bus details are as follows; 1996 Prevost XL 45 chassis  The engine is a 12.7 Liter Detroit Diesel Series 60 engine that is a six cylinder.  Transmission is an Allison 6 speed.  Vanner model 60-100D battery equalizer and vanner model EM70D electrical system monitors are located in engine bay as well (no warning lights on these units, either).  The engine and tranny have worked flawlessly and this is the only issue I have experienced with this coach.  All comments are welcome.

[sstgermain]

Almost sounds like a bad starter solenoid with just the click snd no starter motor engaging

[metalaccents]

any way to test this without the bus running

[sstgermain]

Just jumper across the 2big terminals with a big screwdriver. If it turns over the internal contacts on the solenoid are bad.

[frank.bergamo]

Two batteries at 11.3, two at 12.8? Something amiss there. I would check all connections, making sure they are tight and hooked up correctly. Those two batteries are essentially dead. Hope this helps.

[wildebill308]

1 hour ago, metalaccents said:

The voltage reads as follows in each battery; Bat 1 - 12.86v, Bat 2 - 11.35v, Bat 3 - 11.35v, and Bat 4 - 12.86v. 

Strange that the batteries are that different in charge. The 12.8 are full charge and the 11.3 dead. Sounds like something isn't hooked up right.

Bill

[hermanmullins]

Sounds to me like a bad alternator. Had the same issue last year going to Perry. If you can pull the two batteries, have them fully charged. It should start. 

My problem was the alternator. When it was replaced problem solved..

Herman 

[erniee]

Check out prevost owners group on Facebook. Gil Johnson is the guru there. 
On my 97 Liberty, it was a power hungry beast and needed to be plugged in or generator running. Unless you turn off all the master switches, the coach’s’ parasitic draws will deplete your batteries in no time

[rls7201]

There should be a relay system to get 24 volts to start and then revert back to 12 volts so the alternator can charge every thing. I suggest that system has failed. Thus 2 charged batteries and 2 dead batteries.

 

Richard

[kaypsmith]

Sorry that I have been out of pocket for a while due to outage of internet. I just read your post and hope that you have your problem resolved by now. But in the event that you haven't, I will attempt to help explain your problem. Your alternator should be a 24 volt alternator as those beast have a 24 volt ignition system in the chassis, no relay in the system to revert back to 12 volts. The bus came equipped with an equalizer to keep both 12 volt batteries or series of batteries to maintain 24 volts. The equalizer may have gone bad or may have been miswired which will cause the problem. A normal RV, not a bus conversion technician does not know how to deal with this issue will probably be of no help in resolving your issue. If you have not resolved the issue by now, you will need to consult a bus repairman, not an RV tech. Please reach to me by sending me PM here. I have been running a bus conversion for years now and do most of my own maintenance.

[metalaccents]

Sorry it has taken so long to reply. The issue was resolved by replacing the battery equalizer.