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Coach Batteries
HI
I have had this issue a couple of times. After running the bus for several hours, I shutdown where we were going to park the bus. When I went to start the bus, it turned over great, but would not start. I found in the past, this would happen if I forgot to turn on the 12 volt. In this case, two of my coach batteries were over 13 volts and two were only at 11 volts. Once I charged the two batteries above 12 volts, the coach started right up.
My question is what would cause two batteries to not charge? I’m use to using my volt meter to troubleshoot, but not sure where to start. My trickle charger usually takes care of the issue if I’m parked for a day or longer.
Now that I have been thinking of this, I’ll take a look at my wiring diagrams and see if I can see what might be going on, but any thoughts from the group would be appreciated.
thanks
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7 Replies
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Looking at my wiring diagram, the DDECII is getting it’s power from a battery equalizer that gets it’s power from the batteries. there is also a cut-out switch that is also pulling 12 volt power directly from the batteries and could connect directly to the DDECII. If anyone would like to see the wiring diagram, I could take a picture of it and post. The way I’m reading this, all my batteries should be posting the same voltage. Note that I replaced all four batteries a year ago.
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Rod,
You should load test each battery to determine if you have a bad one or more. You have to disconnect the cables after fully charging the batteries to get accurate readings. DDEC is not normally connected to the Equalizer, so not sure what you have going on there. Maybe they did it that way back in your vintage, someone else may jump in here.
How are you charging wtih the trickle charger? The batteries are in series/parallel so you have both 12 and 24 volt.
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To the best of my knowledge some DDEC circuits are “hot” all the time. I think where the direct connection is depends on the vintage of coach. On a coach I had for example the DDEC circuits were powered directly from the 12V terminal on the chassis batteries, although I see no reason to not connect to the equalizer.
I do agree with Tom and would check to make sure someone hasn’t gotten creative by comparing the coach to the Prevost wiring diagram.
FWIW there is little that is more frustrating than a bad battery in a set because whether it is chassis or house it is not uncommon to find battery issues presenting syptoms that do not make sense and his advice to check the batteries may be a little inconvenient because you need to disconnect the cable, but is an important step.
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Rod: Check the batteries as has been suggested. Its possible you have a battery with a bad cell or something else wrong with it. I had new chassis batteries installed in May and one of them failed in October! Replaced by Interstate under warranty.
If one of them is bad and the rest of them are four years old, I understand they ALL should be replaced at one time. Someone else will have to post the reasons why, but it makes sense to me. Mine weren’t old enough for a full replacement, so I replaced just the bad one.
Following Jeff Rowe’s instructions, I removed my batteries so they could be tested and put them back in using the procedures at the following link:
http://prevostcommunity.com/forum/threaddetails.asp?Category=Electrical&ThreadID=3436
Any questions, please call me: 262-365-9088.
Then again … you might have another problem. Good luck!
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thanks everyone for the suggestions. I did replace all the batteries at one time. I replace the original batteries because they didn’t hold the charge after being charged back up to the proper voltage.
thanks again
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Were they all soft or just one or two?
Smart replacing them all. When they are that old, when you replace one you must replace them all.
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I think if changing batteries is needed (after checking them individually) I would insure the charging system and equalizer are working. If the equalizer is not functioning the batteries will not get charged properly.
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