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chassis batteries
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Ace,
It’s a good thing you’re not asking Jon that question!!!
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My cell phone has a rotary dial. No camera, no text, no voice mail.
Only kidding about the rotary dial.
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Tom is that some sort of military phone for the field?
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I don’t know Rick, I just grabbed it
off the net to agitate Jon. -
Rick,
It sounds like you need to determine if the problem is the batteries or a phantom load. If it is drawn down in such a short period of time you can quickly rule out phantom loads by shutting off the master switches (the big one and the 12 volt above it.) That should turn off all but the direct connection to the 3 DDEC circuits that goes from the batteries to the electric box (CBs 19, 20 and 21 I think). Take a look at the batteries just to make sure that no wire other than the one to the DDEC is coming from the batteries. Since you just changed them out you probably know that.
With the master switches off monitor the battery voltage. You should see virtually no loss over a day or three. I can go months with only about a 1/2 volt loss from good batteries.
If the batteries don’t lose voltage there is a load somewhere pulling them down. If they lose voltage that is measurable over a day or two, separate the batteries and test them. That should be a good start to finding out where to look for the problem.
FWIW I never turn off the master switch on the chassis on my coaches and the first one I had a problem initially that turned out to be a load the previous owner put directly on the chassis batteries. It was for the heater in the Racor.
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Rick,
There is very little draw from DDEC at your chassis batteries, so someone along the way may have used the chassis batteries as a power source. If you have a clamp on amp meter, you can identify the source.
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I disconnected each battery and load tested. All ok. Hooked to batteries is 12 and 24 v wire from equalizer,ddec wires and battery charger. Just to see if there was any difference I disconnected the charger and nothing changed with the 2 main switches off. So now I presume I have a phantom load in system with the switches on. Question is where? Where would be a good place to start with an amp meter. I bought one today to figure this thing out. Rick
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Rick,
Since you recently changed batteries use the wiring diagram on the door and double check the cables to make sure they go exactly where the diagram shows.
Then check it again.
Once you are totally satisfied the cables from battery to battery and to the equalizer are OK then you can look for the loads. Over time previous owners often modify a coach, and few make notes or mark the changes. Fewer still make a modification with the thought required to equal the quality and logic Pevost and the converters apply to their work. You may have to painstakingly look for current draw starting at the batteries and then working your way to the bus bars and then the individual circuits. Since it is chassis related it is possible the load may have been added to the posts in either the front or rear electrical compartments, and that current draw is going to be a post or terminal that is hot with the key off. Your tester can help you find those, then it is a matter of determining what is connected to those posts or terminals.
Have patience. you will need it. If you are lucky the load will be obvious due to the quality of the wiring and connections not be equal to what Prevost or Liberty did making it stand out. Look for in line fuses instead of a factory installed circuit breaker as a clue. Look for colors that don’t match the Prevost yellow and red for hot wires.
It took me months before I stumbled across the phantom load on my first bus. As soon as I found it however the clues were all there, I just didn’t know I was looking at them.
BTW, if this phantom load issue was not there prior to your battery change………you know the first place to look. Did I tell you to check the location of the battery cables?
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I ckecked the battery cables, all are hooked up correct. They are all color coded and there is a diagram on the door.
This past spring I replaced the batteries. We took 6 trips with the coach this summer and all was fine.
It wasn’t until just reasently that I had an issue. Soo the hunt is on! Rick
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Any time something unexplained pops up as a problem, the first place to start looking is the last thing done to the coach. If nothing has been worked on, or if no device is seen to be “on” then you have to be a Sherlock Holmes and start methodically looking for loads. If you want some good news, at least it is not intermittent.
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Rich has anything been added to the electrical panels under the drivers area. I had no problems until I connected a compressor to a 12volt terminal in the Drivers/steering bay and Bam when I went to leave the park I had no juice to start the engine. So your phantom maybe at any junction box that connected to the chassis bats.
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Greg I have’nt added anything to the coach but thanks for the idea. I think I’ll start with in line fuses which
I have found a couple so far. The problem is there somewhere and I’ll find it. For now I’m going to manage
power by shuting the 2 main switches off. If I don’t find the problem before we leave for Florida I’ll have
something to fiddle with when we get there. Rick
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To draw the batteries down as fast as you describe, one of the fastest ways to find which circuit(s) have a load on them is to work on it in a relatively dark place and just disconnect electrical connections one at a time. The one with the load will show a spark. The load is not going to be very small.
If you did something yourself to cause this such as leaving the lights in the engine compartment on you are not obligated to confess. Feel free to make something up to explain the problem.
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Ck your air line comming off compressor to see if it has rubbed against battery cable where they pass. Remote idea–rubbed hole in DKO’s air line in past.
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