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Bus not starting
Hey Guys,
Need some help and input… went to pull the Bus out of the garage today and it wouldn’t turn over…
Got a Bat HI/Low and a Bat Bal warning on the dash. Bus really hasn’t been driven any real distance or run for any extended period in more than 2 months but it’s been started to pull in out of garage for washing waxing etc…
I tried to use the jump start button and same thing would not turn over…
So I call prevost 24hr… and they talked me thru a few things… Chassis Batts were only showing 10.4 which they said wouldn’t be enough to start it… So I put it on a charger and have got it going and let it turn at high idle for 15- 20 minutes…. Going to charge it some more…
The Chassis batteries were all replaced end of 2011… Coach is always plugged into shore since I got it in december…
Prevost guy said that the chassiss Batts are not charged when on shore power which surprised me a bit…. and it might just be an issue of me starting it for quick in and outs and not letting it charge back up… I always kill t
Do you guys buy that? Any suggestions? Should I have someone take a look at it…
I am new to all this… he was great and walked me thru how to charge it etc…. he indicated that explained that there are 4 batts for the bus… 2 I think he said were 12V and 2 were 24V… not sure what I am doing wrong but I am getting 24V or higher on all of them when it’s running… I thought I heard him say the two for starting were supposed to be 12V Feel stupid asking but how is one supposed to check voltage…
I tried postive and negative on the middle of the three stacked in a row and got the same as when I did Pos of the first battery (closest to engine) and Neg on middle….
Any help would be appreciated….
Thanks
Bill
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11 Replies
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Bill,
I am not familiar with how Marathon sets up their electrical system, specifically how they provide for maintaining a charge on the chassis, if any.
But, unless your house electrical system provides a chassis battery charging system that can be used for maintaining the batteries like the quality of battery maintenance the inverters provide you need to monitor chassis battery condition and possibly provide them with a charge.
On my coach for long term storage or keeping the batteries charged after I loaded them, such as when working on the lights I have a dedicated 24 volt charger powered off the house AC panel. For emergency starting some conversions have a way to tie the house and chassis together for starting purposes.
As an owner you will benefit highly from learning from Marathon or other owners how your coach is set up and how to monitor it.
The chassis batteries and likely the house batteries are set up for 24 and 12 volt loads. Because of that you are going to have equalizer(s) which maintain a specific relationship between the 24 volt side of the battery set up and the 12 volt side. The equalizers maintain the 12 volt side at 1/2 the voltage of the 24 volt side within 1/2 volt. You not only have to be aware of and monitor the 24 volt side, you also have to know the 12 volt values and insure they are 1/2 the 24 volt values.
To check chassis voltage the easiest way is to use a multi-tester and you can read the chassis voltages either at the batteries themselves, or at the terminals on the equalizer, or at the terminals on the Vanner Monitor. Remeber, those are only chassis voltages.
The house battery voltages should be read at the batteries if accessible, or in the coach DC bay or distribution point, or at the inverter remote panel. Wherever the house voltages are checked you need to be able to get both the 12 and 24 volt readings. If you can find the house battery equalizer that is a good spot to check voltages.
I hope Marathon owners can get specific as to where and how they are able to access a place to read voltages.
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Your closer than you think! To ck each batt voltage go from + to – on that batt should read about 12.6V full charge. A very small load can draw the batt down over that amount of time. To explain how you 12volt and 24 volt Prevost factory system(not converter) works. You could go to prevostcar and look under wiring diagrams for your coach. Last letter and last 4 numbers of your serial # will give you bus system pre-converter. When at high Idle your dash charging unit should read over 26-27.5 volts in your batt condition. I use a batt maintainer on chassi batteries and shut master batt switch(if yous has it) when parked for a period of time. One of the Marathon guys will chime in that knows what they may have changed over Prevost factory. Bob
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Jon and I were typing at same time. Hope you can get something between the two.
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Many Vantare’s do not charge the chassis batteries from shore power. It is why so many have installed the Guest Battery tenders (Marinco) to maintain the chassis batteries while on shore power or in storage.
I think it is the Guest 10 Amp Dual Battery ChargePro Charger 2611 (A/B). About $1000
You will find it designated as an “A” or “B”. This was confusing to me because I couldn;t find a difference. When I chacked, the “A” designation is for the consumer single packaged product while the “B” designates a case packaged product purchased by Yatch makers and converters.
http://www.marinco.com/product/10-amp-dual-battery-chargepro-charger-0
Also, if my coach has been sitting and the batteries are discharged to where they won’t push the starter, I yank them and take the to Interstate (I have Interstate chassis batteries) for full charging and testing. You might have one bad battery that is bring the rest down. I have seen that several times. I might have to leave them overnight for full testing and equalization charging. However, I am not guessing as to what the issue might be.
Just make sure you take pictures, draw diagrams and clearly label all of the connections. It is a good time to clean all the connectors and use a battery terminal preservative on re-assembly.
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Saw Bill’s post and reached out to him just a few minutes ago on the land line.
Sounds like four (4) new starting batteries will be in his future.
AL
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Al,
Did you discuss a charging system with him for his chassis batteries? Not up on how your vintage Marathon is setup, my 97 needed a Guest that I installed.
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Tom,
I think the plan is to check out the existing batteries for service. 2011 replacement but the big question willl be how old are the battteries.
Marathon use a 4 bank 31 series set up for engine service only.
Had the exact same chain of events last year finding one of the 4 2009 batteries had crashed.
It makes good practice to pre check everything a couple of days before travel. Bill has a couple of weeks before his trip and much better in bus barn then a no start in a RV park with the family ready to go.
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Same thing to me today ready to go and just click click click have taken all batterys out and charging i have no idea how to charge all at once with my 12 volt chargers all tough mine is a Vantare
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David,
How old are your starting batteries ? Not the date installed in bus …but mfg date.
AL
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Al, And everyone…. thanks a bunch….what a great group…. post a need for help and folks actually call you to offer assistance…
So here is the update… I followed the instructions by prevost 24 hr. support and individually charged the two batteries that are setup as 12V
Everything is showing good and I have moved the Bus out and have the tow car all hooked up and ready to take a 70 mile trip tomorrow morning to get the airforce one installed in the new towd car…
my plan was to keep my eyes on things and see what happens…
based on my only other Prevost repair attempt with the voltage regulator not sure I want to try to do this myself if replacing the batteries is what is needed although not positive they are… I guess the only way to know that for sure is to pull them all out and load test them..
Thanks again!
I will keep you posted!
Bill
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I have had a Liberty installed charger for my chassis batteries on all my coaches, yet I may have actually used the chargers perhaps 5 or 6 times over the 23 years of coach ownership because unless something pulls down the chassis batteries they maintain their charge between trips, even if I go several months before using the coach again.
Even when I am not using the coach I do check voltages regularly which I think is a good practice. If you do not have a charger for the chassis I think it is a good idea to add one and the Guest is a good one. I would not recommend leaving a charger for the chassis batteries on all the time because it is not needed, and because unless the charger is a “smart” one prolonged use could actually damage the batteries.
But step one is to know the coach and make sure it is checked routinely. A set of batteries that loses a charge over a short period of time is bad, and a charger left on continuously masks a problem that can leave you unexpectedly stranded unless you have a way to jump start the coach.
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