Electrical Problems - 2003 Safari Cheetah

[CountryGentleman]

I recently purchased a 2003 Safari Cheetah with a 330 hp Cummins Diesel engine. Things were fine up until about two months ago.

Then the one year old Cat chasis batteries went dead. I replaced them and about two weeks later they went dead again. When I say dead, I mean the specific gravity readings are zero and the batteries will not charge with an external charger! I replaced them a third time and again, they died. I then replaced the Cat batteries with deep cycle batteries from NAPA. These worked fine for about two weeks but then the alternator fail light came on.

I replaced the alternator but again it would not work. An RV mechanic determined that the alternator was OK and worked fine when an "excitor" wire was hooked to the house batteries. This worked fine for about a week and now the chasis batteries are dead again. The voltage reads 10.5 but the specific gravity is zero and the engine won't crank at all. The excitor wire was a temporary fix. It is not permanently connected. I simply touch it to the battery and the alternator begins charging.

Monaco has been virtually no help. There is no drain on the chasis batteries and the isolator appears to be working fine. Has anyone else had this problem???

Thanks

[ExigencyResolutionManager]

I also have a 2003 Cheetah.

I have had electrical problems with my house battery bank draining.

I tossed the factory batteries and went to Glassmat batteries, which lasted four years before they were toast, and they were foamimg toast when I looked at them ( I was on assignment in another state for a year).

There is something integrated through the inverter that draws power with the main coach disconnect turned off; I have not traced it, but it will draw on my engine batteries.

Not an answer but another place to look for the root problem.

[shields]

Hi CountryGent,

First of all, welcome to the FMCA Forum. You'll find a lot of help available here.

From your description, four sets of chassis batteries have died within a short period of time. Clearly the trouble is not defective batteries; they failed because they were discharged so deeply they could not be recovered.

It seems you are faced with one or both of two troubles.

1. The batteries are not being charged from the alternator. I'm not sure what an "exitor" wire is, but it seems clear your alternator is not charging the chassis batteries without this wire being connected. Whatever the cause of the alternator trouble is, it must be identified and resolved. Without confirmation that the alternator is reliably charging, no further progress can be made.

2. Something is draining the batteries. Once fresh batteries are again installed, connect a multi tester in line with the with positive lead and see if any current is being drawn when your main battery switch is "off". Then see how much current is being drawn when the switch is "on" but nothing is running. By process of elimination, you can eventually find what is drawing the current down on your batteries.

Since you are sure that problem #1 exists, you would probably be best to address that problem first. Once that is resolved, then you can see if problem #2 is also present. Once both are identified and addressed, things should be ok again.

By the way, what assurance do you have that the isolator is working properly?

Please let us know how things progress. Best wishes,

Tim

[halberstadt]

Hello "Country Gentleman". I also have a 2003 Safari Cheetah, and do all my own maintenance. As an aside, you don't really have a Cummins engine - it's a Caterpillar. That's not pertinent to the problem, though. Tim had good advice for you. To clear up the "exciter wire" thing, that wire is actually not an exciter wire, but rather a remote voltage sense wire. The alternator will adjust its output voltage such that the voltage wherever that wire is connected will be 14.7 volts. It is supposed to be connected to the positive connection of the chassis batteries (or a point that is itself connected to that). Monaco/Safari ran that wire to the isolator and connected it to the post of the isolator that goes to the chassis batteries. That wire, and the one that feeds the "ALT FAIL" light relay, are often subject to corroding and breaking where they connect to the alternator, either of which would give an "ALT FAIL" light. In your case, the remote sense wire could have broken anywhere, maybe at the isolator. As long as you now have a good connection from the alternator remote sense post to the chassis batteries or isolator, that problem should be fixed.

As Tim suggests, the best next step is to identify if there is a current drain from the chassis batteries, and if so, where it is. I use a multimeter that can clamp around a wire to read the current flowing through it. The most common version of this "clamp-on" ammeter reads only AC current, but there are (more expensive) models that also read DC. If you can find someone with one of these, you can identify which wire leading from tube battery is carrying the unwanted current, which should narrow the possible culprits.

Someone mentioned the inverter, but your inverter does not connect to your chassis batteries. I would check the isolator. With the engine running and batteries not significantly discharged, you should measure one voltage (around 15.5 volts) at the center connection (the larger one that comes from the alternator, not a smaller voltage sense wire), and about 0.7 volts less at each of the other two connections (chassis and house battery connections). With the engine off, the alternator connection should read zero and the other two should be around 12 volts or so.

Bill Halberstadt