chassis batteries

I have gotten two different stories from two different people at marathon, so now lets see what everyone else has to say.
the question of the day is,...
are the chassis batteries being charged or not when the bus is plugged in.
I understand the house batteries are being charged but some tech guy at marathon said, shore power is also charging chassis batteries at the same time.
someone else at marathon says no they are not.
before the test of time shows me the answer, I would like to know what to expect, I have a 24v charger so do I put it on or are they already being charged.
and, if I am about to be told to put a charger on them where do I put the charger so it charges both the 24v and 12v.

Here is a very easy way to see.

Look at what your charger is doing at any given time while plugged in or on gen power with the inverter/charger on and with nothing powered off the chassis batteries, on.

Then go and turn on a bunch of chassis stuff, high beams, marker lights, radios, whatever and the charger will increase its charge rate if it is charging them.

If the charge rate does not change, it doesn't.

It really depends how it was done.

Although ours has a 24 volt equalizer switch, we can not get a charge for the chassis batteries from our charger with it on. It will only allow the house to draw off the chassis.

If I am going to be in one spot for a long period of time and are going to have the bay doors open alot I will put a shim on the micro-switch for the bay lights cause I have had dead chassis batteries once after doing that. I also then turned on the 24 volt equalizer at that point to try to start the bus with dead chassis bats. to no avail.

A small trickle charger for the chassis batts plugged into the engine bay outlet will remedy this for cheep and easy if you find that they do not charge.

My 93 Marathon did not charge my engine batteries when I was plugged into shore power, so I installed a 24 V charger that would charge then go to float so it didn't damage the batteries. I kept mine plugged in the same outlet in the engine compartment that was installed to accomodate the block heater. I just verified where I had 24V on my engine batteries and permanently installed the leads to those terminals. After installing the charger, my engine batteries were automatically charged when I plugged into shore power.

My 2001 Marathon did not charge the engine batteries when on shore power,so I added a small trickle charger.

Like Dale, I installed a 24v battery tender and plugged it into the block heater receptacle, but you have to either unplug it or turn off the breaker to the receptacle when coming off shore power. Mine didn't like trying to work with the inverter as a power source.

Ed, when we are parked for a period of time, I throw the main disconnect on the chassis batts, since they only get charged while running down the highway. Mine don't in any way get charged any other way.

The house side is always getting charged, e.g. shore, gen., Detroit, which also feeds the gen. batt.

Another view.....

The chassis batteries are not charged when the bus is connected to shore power unless you have a provision for charging.

However, despite what some may experience our two coaches never required charging between use or shutting off the chassis main switches. We have gone as long as 3 months with no noticible loss of chassis battery starting power without maintaining the charge or turning off the master switches.

I would suggest if the chassis batteries are losing power over a short period of time you have a phantom load that needs to be identified and possibly corrected.

Wow, I didn't think I would ever be here asking this question but here goes: My rig had been sitting for about 45 days, plugged into the shore power when my son heard the 'voice' inside the coach stating that the chassis batteries were low. I discovered the ignition key was in the accessory position. I then tried to start the coach but to no avail. I called my road service. They tried jumping the batteries but that didn't work, either to the Prevost battery studs or directly to the batteries. Without my knowledge he jumped it directly to the starter and had me try it from the cab. It started and I ran the engine for about 1 1/2 hours. When I shut it down it wouldn't restart. Then the voice advised of low batteries and the 'Equalizer' light came on in the dash. I bought a good battery checker and put a load on each of the 4 batteries. After the load was removed the batteries showed about 12V or just a hair less. I charged the batteries all together using the jumper studs until the batteries were fully charged. No luck. Everything was the same as before. The engine will not start from the front or the back and I don't even get a solenoid click. I don't find anything in my manual that shows a reset but I am guessing this may be something simple. I hope so! We are getting temperatures down in the teens so keeping these batteries from freezing is a must. At least for the moment the meter shows that they are fully charged. I hope one of you smart guys out there can offer me some advice. I suppose now would be a good time to apologize for some of the wise-a$$ remarks I made to some of the great POG members!:(:(

Sounds like one of the large red pop out circuit breakers has popped out...could be one next to the stbd. side engine room door. They are hard to detect as being popped and take a really firm or hard push to reset. Just a shot in the dark.

All of this discussion forced me to take a look at my bus to see what is happening to the chassis batteries as mine sits for the winter. On my bus, Country Coach installed a seperate 24 volt charger for the chassis batterries that works when the bus is on shore power or running off the generator. Seems like there is little consistancy in this business.


Miles and Laura Circo
2004 Country Coach XLII D/S

There is not only inconsistency between the different converters, there are differences in the coaches by the same converters.

My Elegant Lady has a chassis battery charger. Some Liberty coaches do not. So it is no wonder there are differences between converters. But as a coach changes hands the owners also modify the coaches so it is important to either get a very thourough checkout on the coach when you buy it (nobody does because they are so anxious to drive it) or spend the time required to look and learn every feature and device.

I'll repeat this again: If something is pulling down your chassis batteries you need to find out what that load is. There should be no loads on the chassis batteries with the key off, and ESPECIALLY with the large Prevost master switches turned off. If that is not the case, at the very least you have a fire hazard, and you likely are going to have battery problems plague you during your years of ownership.

Darl,

Toy Box has a good point on the breakers. You need to be a little more specific on a couple things.

1. You tried to jump start using the 24V Prevost lug with a 24V source?
2. You said you charged the batteries with the stud, was your charger 24V
3. If your getting an equalizer light now, you may have fried it
4. When you load tested the batteries, did you unhook them completely
5. We assume the 24V and 12V cut-off switches are on
6. Is the rear start switch in the normal position
7. Do you have the digital dash

Just went thru same thing. I only have small 12 volt charger so I unhooked all wires and charged each battery 24 hours and everything works fine. I do have a 24 charger on order to have a permanant solution. Before charging, I would only get a clunk when turning key on. Best of luck, Dan

Quote:

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Originally Posted by truk4u

Darl,

Toy Box has a good point on the breakers. You need to be a little more specific on a couple things.

1. You tried to jump start using the 24V Prevost lug with a 24V source?
2. You said you charged the batteries with the stud, was your charger 24V
3. If your getting an equalizer light now, you may have fried it
4. When you load tested the batteries, did you unhook them completely
5. We assume the 24V and 12V cut-off switches are on
6. Is the rear start switch in the normal position
7. Do you have the digital dash

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Tom, Jon, Danss and Toy Box, Thanks for the good advice. I just finished going through everything you recommended but everything is essentially the same.

First this problem was caused (I think) by leaving the key in the accessory position for a long period of time. I have never had a problem with a parasitic drain in the 14 months I have owned this vehicle and nothing has been added that would cause a drain. In the past it has been idle for almost 2 months at a time with the 12V and 24V switches engaged.



Toy Box; The 1st thing I did was check the red breakers, making sure to press them firmly. None were tripped.

Tom;
1. I thought my charger was 24V when I used it on the Prevost lug. It is 12V.
2. I disconnected each battery individaually and checked each with a load. They indicated a about 12V before the load was applied and slightly less after. The instrument instructions states they can go down to 9.3V at 30 degrees. The temperature is a lttle less than 30. All batteries check the same with only a slight variance.
3. I topped off each battery separately, each disconnected from the other. 4. No indicator or voice regarding the "equalizer".
5. 12V and 24V switches were on in previous check and same today.
5. Rear start was and is in the 'Normal" position.
6. Dash is analog.

When I tried starting I could not hear a solenoid click or any other noise from the cab or when attempting a rear start.

The battery gauge inside the bus moves up slightly and the charge indicator shows 14V.

The fuel gauge does not work. Not all marker lights illuminate but the headlights come on bright. The turn indicators do not work at all.

The coach is plugged into shore power so the coach batteries are fully charged. The 17.5 KW power plant fires up and runs great. When this problem first occurred I ran the generator for a while hoping that it would charge the chassis batteries. ( I think I read somewhere on the Forum that some coaches are configured so the generator will charge the chassis batteries.)

In my original post I noted that the 2nd insurance service provider that tried to jump the batteries connected his vehicle battery jumpers directly to my bus starter which started my engine. After running the engine for well over an hour nothing changed. It would not restart.

I am completely befuddled by this problem. In the end I tend to believe that the batteries were never really dead but if that were the case why would the engine fail to start or at least make a clicking sound from the solenoid?

This is a '97 Country Coach XL45 but has a '96 chassis.

The engine/computer is a Detroit DDEC-III.

Logically this seems like a simple problem to remedy but my old brain is not working logically. If anyone here has an idea, no matter how absurd it may seem please let me know.:confused:

Thanks, Darl

Darl,

When you turn the key on are you getting all normal dash indications, such as the gauges and the indicator lights, and if so does the two go out to indicate it is ready to start?

It sounds like a tripped breaker in the big box in the rear or a bad relay. I'm not at the bus and don't have my books, but my first guess is there is an open circuit somewhere because your voltages seem good.

Two more things I would check.

First the ground. If a thorough inspection of that checks out:

Next check the smaller wire to the starter for a loose connection, also check the post it is attached to to make sure it cannot be twisted and is firmly affixed to the solenoid.

If that checks out then have someone put the ignition switch to the start position while checking that small wire at the starter with a circuit tester, it should light up in start mode.

If the wire is tight and it does light up, I'm baffled cause you said that it started with a jump at the starter. If you get lucky you will find no juice at that wire, or a bad connection.

If it shows no power and the connection is good the next place to go is the ignition switch and its circuit protection with the circuit tester.

Darl,

Forgot to mention, when I had a problem with a tripped breaker (one of the big ones) I pushed hard and it seemed like it was set. I checked with my meter and it was still tripped open. I finally had to use a tool to push on it because I could not exert enough pressure with my thumb.

It may be worth verifying all breakers are closed.

Not hearing that click means that the engine run relay (solenoid) isn't closing.

I'm going down to the bus rather than guess any more.

Darl,

I'm a little bit smarter now that I looked at the bus. Not much but a little.

Here's my recommendation. Make sure you have 12 and 24 volts in the coach. That is step one. There are a number of places to check such as the posts in the box in the rear and at several point in the front box. I suspect from your description of what you have and what you do not have working something is funky.

You need to verify those breakers are closed (the big ones on the side above the black master shut off switch.

Then check all the small breakers in the front and rear electric boxes. Several relate to the start and run circuits for 12 and 24 volt. Pushing the circuit breaker trip button and resetting is all I would do at this point.

Then using rear start see if it will start from there. When you hit the start button you should simultaneously hear R4 (the big relay or solenoid) and the starter on the bus. If not, test for power to R4, with the start button pushed, and check for a complete circuit between the two big posts to insure power is getting to the actual starter solenoid coil. If it is, follow Joe's post. If it is not check the relays for 12V and 24V run front and rear boxes. I think they are R53 and R54 in the rear.

It is just a question of finding where the electric from the batteries stops.

Jon and Joe, Since it is colder than a witches 'you know what', I will wait until the morning and go do the things you two suggested. Actually I do not have a full dash. The voltage and battery gauge work but the fuel indicator does not. It seems to me like a fuse or breaker problem since it occurred while the bus was parked and I wasn't poking around inside any of the various compartments. Regardless, I will check it out in the morning and let you know. I really appreciate your help! Darl

Darl,

I'm going by memory from something I think I picked up a long time ago so it may not be accurate. Some of the dash functions are controlled by some of the relays or breakers in the rear. As you mentioned you do not hear the click when the key is turned on but that indicates to me that a CB tripped or one of the relays is not functioning. Since the rear start also does not function you should look for a relay or breaker common to both front and rear start.

I'll poke around in the AM also and pull up some wiring diagrams if they are readable. It has to be something simple.

Darl,

I'm on my second cup of coffee and with wiring diagrams in hand I think the issue is one of not getting power to the start circuit.

Verify there is power at the starter. You should have 24 volts on the big cables, the positive and ground. The power to these terminals goes directly from the chassis 24V battery post, through the cut out switch to the starter solenoid post. I have two diagrams and do not know which is applicable to your coach. The second one shows a relay in that circuit, but I do not think that applies here. (That's a guess)

If you have power, then the simplest start circuit is the rear start. It has the fewest possible failure points. You should have 24V power at the rear 24V junction block. If not look at the 90 amp breaker CB5 which should be near your cut out switch.

If you have power, select rear start. Power then runs through CB16 to the rear start button, from there to the rear start switch, to the large relay (solenoid) R4 coil. When you push the start button in the rear you should get 24V at that solenoid coil, it should close the contacts allowing 24V to run to the starter solenoid coil.

Since you lack all dash gauge indications I'm thinking your problem lies with the 90 amp circuit breaker or a relay related to that if you coach has one.

Keep posting your progress. I'll keep checking back. bear in mind the wiring diagrams do not list coach serial numbers and I have narrowed it to the two which may be applicable. One has a relay but I suspect strongly yours (and mine) does not have that relay.

Darl,

Thanks for the response, John's got you on the right track and I'm glad you don't have the digital dash. Some of the questions I asked sounded stupid, but it's easy to overlook stuff. Sure sounds like a breaker problem. You said the dash gauge showed 14V, what did the 24V gauge show?

Keep us posted.

Hello Darl,

Your reading on your batteries should show: 12.7-12.8V not "...12V or just a hair less..." Your batteries needs charging.

Darl,

Alek's post is correct. When I talk abouit 12V and 24V those are nominal values. At the 24V terminals on the starter and at the 24V post in the rear junction box you should see no less than 24.4 volts and the best voltage would be around 25.4

Jon, Joe, Alek, et al, Thanks for all the help! I have followed your advice and here is where the situation stands; first I did the obvious (some of which I had done prior to my plea for help) checked the circuit breakers, like R5 and all the large 12V and 24V breakers near the rear cut-off switches. This time I pressed them extra hard and pressed the reset button on all the small breakers inside the rear engine compartment and in the compartment below the drivers seat. I tried to start from the rear. No luck. Same with the cab ignition. I then used my battery tester and came up with almost 13V on all batteries. Testing the the post with the red plastic cover on the starter, grounded to the frame, yielded a value of 13.3V. I didn't have anyone to press the starter button so I didn't get that reading. A reading from the jumper lugs was 12.9V. I decided to use a different electrical tester. I now have a 11.9V on the batteries with that tester and 12.3V, after applying a load for 15 seconds, using the other tester. At this moment I have my chargers on individual batteries that have been disconnected from the others. Charging at 10 amps for 2 hours.

I hit my head a 3rd time on the battery door light switch causing it to start bleeding again (some folks never learn), the outside temperature is now above freezing but the wind is blowing about 30mph with gusts to 50:eek:. The good news is the sun is shining!:) I will go out to check the charge in a couple of hours and post the results. Oh, the Battery gauge inside the bus moves a bit and the Voltage gauge reads 13.5 volts.

Finally, if the batteries test at 12V or slightly less wouldn't there at least be a solenoid click or would there just be silence?

Again, thanks to all. I will give you an update as soon as I have one.

Testing the the post with the red plastic cover on the starter, grounded to the frame, yielded a value of 13.3V.

The red hot post coming from the batteres at the starter should be 24V or above. Fully charged mine reads 25.8. Maybe I misunderstood the above post.

Darl,

I agree with Truk. The wiriing diagrams I have confirm you should have 24V at the big starter battery connections. The only 12 volt you should have is for DDEC.

Try not to bang your head any more, or at least wear a thick soft hat.

I don't know if you would hear a click BTW. at some low voltage DDEC is disabled and I don't know if other relays will fail to engage at low voltage.

Hi Darl. Depending on the age of your batteries and the number of times they have been drained down, they will not come back up. The best thing to do is to take them in and have them load tested. If they are all the same age and several are bad, replace all of them or the new batteries will get drained by the older batteries.
I left my ignition on by accident and drained my batteries down. Because I failed to check water levels & proceeded to charge the batteries, I fried them all along with my regulator. I am not saying this is your problem but a series of events can exacerbate a simple problem.

Gary, the Interstate batteries are only 14 months old and still under warranty but I am beginning to think that is the problem. When I put my small, automatic charger on one isolated battery it charged up to over 13V. I am now charging a 2nd battery overnight and will check in the morning if the 1st held the charge. If they appear to be OK I will do what Tom and Jon suggest and check the output at the starter for the 25.8V that Tom gets at the starter. If that fails the next step will be new batteries.
I sincerely appreciate all the time and effort everyone is taking to help me with this problem. Needless to say joining the POG and meeting such great people has been a very rewarding experience.

I will post an update when I have completed the charging, etc.
Thanks!

Batteries are underappreciated until we really need them. Isolating, charging and testing each one individually is the only way to verify they are all OK, and even at 14 months old if a single one is bad it may be better to replace them all. I hope that is not the case.

Darl, after all of your posts and everything in between, even with reading them carefully, it is difficult to follow what --IS KNOWN-- and --WHAT IS NOT KNOWN--. I think only you know that for sure, so let me list a few things in order for you to go through a process to find out exactly where you are and what is not working. When you find what is not working then you must go through the same process with that segment and find out why!!

Does the key(start switch) give a signal (complete the circuit ) with the starter solenoid?

If the key does work, does turning the key activate the solenoid?

If the solenoid is activated, will it in fact actuate? (test to prove the solenoid is not burned out)

If the key works and the solenoid is in good condition, is the start signal available from the transmission?

Can anyone offer any other (start permitting signals that must be confirmed)

For some of this testing it is easier with an assistant to confirm sounds and test lamp/voltage readings from opposite ends of the bus.
If you can not get an assistant you can make up a buzzer or horn that will give an audible sound that you can hear across the bus, or a test light with very long leads.

I think that you can make tests for the trans. signal (all clear to start) in the left front compartment.
__________________________________________________ ____________

Go back to the beginning with your thoughts.
This was all brought on by the start key being left in the -ACCESSORY- position. Other than the drained batteries and the inability to start have you found any other consequences of the, accidental key on condition?

Something seems to be burned out, open circuit, or arced closed????:eek:

This sounds simplistic, but I am not implying that it is. Each segment has its own set of complexities that must be understood and verified.

I didn't get into making anything up yet, but, well you have suffered enough!!!!!
Good luck JIM

Jim, by starting the coach from the rear we eliminate 100% of everything except the absolute basics. If it won't click or make a noise using the rear start, chasing anywhere else except the things I have outlined will not do anything to isolate the problem.

I listed the drawing numbers if you wish to follow why I have taken that position, and if you follow the circuits and they are OK, at the very least the starter will engage, something that is not happening according to my understanding.

Jon, the most puzzling thing about this to me is that the bus was in fact started by a third party after the key incident.
Why then can it not be restarted now by the same means?
Could that individual have damaged something without Darl's knowledge. Remember Darl said that he did not witness the starting (I think that is what he said anyway)

Jim,

That is an excellent question and I can only speculate. With the DDEC getting powered directly from the wires to the batteries, it is possible for the engine to run even though circuit breakers have tripped, specifically the 24V ones.

If the 12V breakers trip I believe some DDEC functions are affected.

It is possible by jumping directly to the starter, if he hit the wrong terminal with the booster cables it could have tripped one of the big breakers, and possibly others. This is an absolute guess so do not put any credibility in it until Darl finds the open circuit. I suspect this is true because if the big CB trips, there is no 24 feedback to the alternator voltage regulator, so even though it ran for 1.5 hours the field on the alternator was not powered, thus it was not charging the batteries. With the size of the alternator that should have put a pretty good charge in the batteries within that time.

FWIW.

That is exactly what happened! When the guy from the road service was trying to connect to the starter he arced the wires. I saw the flash and asked him what was going on? He lied but I saw the area and it was at the starter. Later when he told me to try starting it from the cab I didn't see where he had made the jumper connection. After the coach was running he told me he had jumped it off the starter. Why didn't I think of that or at least mention this arc earlier? Let's hope it is the circuit breaker like I posted earlier. Thanks!

Jim, thanks for your input. I hope this is close to being resolved. I will let you know.

Ditto to the above post on my Royal and Angola. Both had 24 volt chargers installed but both had a breaker to turn it on and off and I only used it when my chassis batteries went dead like leaving the parking lights on over night. I think leaving the 24 volt charge on routinley just puts wear on the charger and helps cook the batteries (although the charger should trickle down to a lower amperage if they are charged.

On a related note, I just had the thing go bad on me. Those suckers are $400 and I couldn't find a "deal" on one anywhere. I found a local electronic repair place and they fixed the bad component for a $100 bill so FYI. Maybe they can repair my surge protector I put a new thread up on just now now that I think about it. That sucker is $700.

On the Marathons as of 2002, they were NOT charging the chassis batteries off of shore or generator power. I built and serviced Marathons, and am quite
conversant with the way they build their product. The word to customers is
to turn off the chassis switches when not in use, and if the chassis batteries
get low, to use the "JUMP START" circuit to tie the house and chassis systems together for emergency starting. If you really want the straight and
skinny, ask the factory for the diagrams for your coach for house and chassis
battery systems. They will show all of the relevant connections. As good as
a lot of technicians are, anyone that cannot back up their opinion with solid
verifiable information may as well be selling snake oil out of a station wagon.

Have a great day!:D

Darl,

What's up? How are you doing on your starting problem?

Quote:

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Originally Posted by jonnie

Darl,

What's up? How are you doing on your starting problem?

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I think he took the family somewhere FUN!!!!!!!!!!!:D:D:D