Dead chassis battery E350

[groswald]

I went to visit the coach today to check the fit on the new consoles I'm making for the driver and passenger seats. When I got there the chassis battery was dead, so dead it wouldn't even click. I always carry heavy duty jumper cables in my truck so I got it started in short order.

When I did I noticed the courtesy light on the radio console didn't go out after a minute like it is supposed to. It stayed lit for the hour I let the motor run to bring the battery up.

We have an Axis on the E350 chassis. I assume the courtesy lite is a chassis capability since it comes on when you insert the key and goes off a few minutes later. Does anyone know where the controller might be?

I disconnected the light for the time being, but the cluster connector it is part of controls all of the radio console switches so I can't leave it that way.

[FW28z]

I am not sure what you mean by the courtesy light on the radio console?

Are you are referring to say an indicator on the radio showing it is working? I would expect that to be lit while the engine is running.

Otherwise, it sounds a bit like my coach. Whenever you open the door, the overhead light comes on, as well as the running lights on the coach'es exterior. They stay on for about a minute before going off.

All I can offer is a wiring schematic from ford for their cut-away chassis to allow customer (rv builder) connection of items to the chassis.

You can find those details at: https://www.fleet.ford.com/truckbbas...bodybuild.html

Click on the link for your year, then on the next page that comes up, you will find a link to the electrical section.

[JamieGeek]

There is a small light just to the right of the radio in the Vega/Axis.
I've circled it in red here:

I think it is wired into the overhead light circuit--as there is no overhead light other than the standard camper light (which has its own switch on the dash).

I've noticed odd behavior in that light before and even asked Thor about it (it was flashing with a regular pattern when I was having generator problems). Thor was clueless and I didn't pursue the question further once I had the generator fixed (fuel pump).

Even though Thor was clueless they were pretty responsive. groswald you may want to try contacting Thor and asking for a wiring diagram (whats the worst they can do? Say "no").

I've also noticed one of my batteries being low--I usually check ours weekly (and run both engines weekly). After only 7 days I find the battery gauge showing only two or three LEDs lit (1/3 or 2/3) this is with the camper in "store" mode. I have one of these cigarette lighter meters I may put in the Axis:
http://www.amazon.com/Cigarette-Ligh...=1416919259129
(Picked it up for other reasons but it also has a use in the Axis.)

[FW28z]

Ah, OK, I get it now. My overhead light is wired to the instrument panel dimmer switch, and which has that traditional "always on" position when you rotate it one way.

One thing to check is make sure that switch did not inadvertently get turned so it is in the always on position.

JamieGeek - for your house batteries, buy one of these:

B&K Precision 316 Mini AC/DC Clamp Meter, 12.5mm Clamp Opening size: Clamp Meter Ma: Amazon.com: Industrial & Scientific

There are other models available that might be a bit cheaper, but this is the one I have. What is unique about it is it's designed to read lower current (10A full scale (1mA resolution) than most clamp meters (typically 600A full scal with a 100mA resolution).

Either way, put the "clamp" on your battery terminal, and it will tell you how much juice is going through the cable. So with everything off, you can tell if you have any residual items taking current from the battery.

The clamp meters are not as accurate as a traditional ammeter (usually 2.5% accuracy vs. 0.5% for standard meters), but close enough for checking for parasitic loads.

And the B&K meter like I have is great as it can tell you down to 1mA. Since even a LED usually draws up to 20mA, even a single LED left on should be able to be detected.

[JamieGeek]

Good idea. Have to dig out the Fluke.

[Mikerv]

I am have the same problem with the dead battery. While I don't have if fixed I have found some thing along the way.

I disconnected the coach batteries so that I am only dealing with the truck battery. I found that I was having a 600 ma draw with nothing on. This is why after 1 week the battery died.

I troubleshooting this I found that when I pull fuse 31 in the power distribution box the current went down to 200 ma. This fuse is for the instrument cluster. With the fuse back in and the instrument cluster connector disconnected the current would stay at 200 ma. When reconnected the current would go back to 600 ma. The cluster is drawing 400 ma. I am not going to fix this yet but keep the panel disconnected until needed.

Continuing to work on the other 200 ma I found when pull fuse 25 from fuse panel in the cab. the current would go down to 125 ma. This fuse is for the demand lighting. I have not found the light yet but I am leaving that fuse out at the moment.

I still have to work on finding the last 125 ma draw but I have done enough for today and will work on it later next week.

I hope this helps you with some thing I have found.

If you find a schematic of the instrument panel let me know maybe I can find out what is wrong with that where it goes.

[JamieGeek]

Its far easier to just install a knife disconnect on the battery and call it a day:
AutoCraft Top-Mount Battery Terminal Quick Disconnect Switch 20138: Advance Auto Parts
I put that on my chassis battery and haven't had a problem with it since.

[FW28z]

600mA would indeed drain a battery in about a week. Other options might be to buy a solar charger and leave it plugged in during storage.

This is an inexpensive 100Watt charger that I have been thinking of getting:

http://www.amazon.com/Renogy-Foldabl...eywords=renogy

Of course, you would have to find a way to secure it or it would quickly "walk off".

You probably don't have to go with such a big charger if you get good sunlight during the winter. But due to the sun's angle and the yukky grey skies we typically get in the winter time in my area, 100W would not be overkill.

[blw2]

Originally Posted by JamieGeek

Its far easier to just install a knife disconnect on the battery and call it a day:
AutoCraft Top-Mount Battery Terminal Quick Disconnect Switch 20138: Advance Auto Parts
I put that on my chassis battery and haven't had a problem with it since.

me too... one of the first things I did was order two disconnects, only I bought the kind with the thumb screw. Put one on each battery (house and chassis). When I park for storage, they both are disconnected. Only takes a minute.

[Mikerv]

The knife switch idea sound the best. For me charging is not an option but it's a good idea to keep in mind.

I am still going to work on the rest to find out why if I can, but now I have more options.

[HEAVYOWENS]

I have the same problem on are Vegas. I have been trying for two weeks to get some wiring diagrams from Thor or any help. Up till now I have got nothing. Have E-mailed every day the person that I have been working with on a long list of problems. If I hear something I will post it for yall.

[Mikerv]

The best help I have gotten was at pep boys. They printed up a copy of the power distribution circuit for me. The schematic is much better then that ford body builders layout.

[davidgebo]

If you install a quick-disconnect knife switch at the battery, doesn't this require the chassis computer to re-boot every time you re-connect? I know that in most late-model vehicles, the PCU computer is always drawing a small amount to keep engine control memory info for engine control systems. Would the PCU computer have to re-learn engine operation parameters? If so, would this pose a long-term computer problem? When you replace the chassis battery on any vehicle, the engine computer memory is wiped, and it takes a few miles of driving for it to re-learn engine control. My Vegas has had a dead battery 3 times while stored for less than three weeks. In the 3 weeks, I did not start the engine to charge the battery. It is parked right next to my house, so it would not be a problem to do so, but 2-3 week down-time seems a quick battery discharge. I have had other motorhomes that sat for over a month without start-up and had no problems. The dealer claims their electrical check indicated no draw at all, with ignition off. I question this finding, as I have experienced 3 dead batteries in less than a year. I think they just don't want to bother to track down a parasitic drain of some kind, or they just don't know how to do it.

[blw2]

I know nothing about a PCU computer, but I've been doing this since June and so far have noticed no ill affects.

I think that it seems to shift a little harder or at least some different for the initial warmup..... but it seems just like a warmup period for a mike or two.

and my guess, if you are correct, is that the worst that would happen would be less than optimal efficiency for a few miles...
and likely no different than you would see if the next start up was in different weather conditions.... like say if it was last run in the winter, then stored through most of the spring to more summer like conditions..... seems to me that any such computer would have to "learn" the new conditions....

[JamieGeek]

Not to mention the "sudden" difference in gas formulations.

I installed the battery disconnect late last year and have seen no ill effects from it. I'm also running both engines about once a week. In the dead cold of winter I would run the V-10 for a good 30 minutes or so--at least until it was up to operating temperatures. Over the course of winter I burned about 1/4 tank doing this.

The couple of times I've driven it after extended storage and disconnecting the battery I have not noticed any difference in behavior/shifting patterns/etc.

[Rlaugh]

Originally Posted by JamieGeek

Not to mention the "sudden" difference in gas formulations.

I installed the battery disconnect late last year and have seen no ill effects from it. I'm also running both engines about once a week. In the dead cold of winter I would run the V-10 for a good 30 minutes or so--at least until it was up to operating temperatures. Over the course of winter I burned about 1/4 tank doing this.

The couple of times I've driven it after extended storage and disconnecting the battery I have not noticed any difference in behavior/shifting patterns/etc.

We have the same problem of the both the chassis and house battery draining, can you tell me does the knife disconnect get connected to the negative post, or can it be connected to the positive side. With it being connected to the negative, it is not easily accessible without removing the interior portion of the dash.

And with connecting a disconnect to the house batteries, there are 2 batteries, do I connect one to each or if I attach it to one, will it disconnect the other battery too?

Thanks for your help!

[FW28z]

I see no real reason the knife switch has to be on the negative side, other than a possible safety issue. If the knife switch was on the positive side, it might make contact with a part of the metal chassis that is connected to the negative side when switched off.

But since electrons flow from negative to positive, it is more proper I suppose to disconnect the negative side.

But there are millions of DC sources switched at the positive side.

If it were me, I'd use a marine-grade disconnect switch rather than a knife switch.

Typically the marine ones connect to the positive side. If you have batteries in parallel, ideally you want to disconnect the batteries from the coach and each other.

If you leave the batteries in parallel, they will equalize the state of charge between them, so if one battery goes bad, it will drain the other.

There are marine versions of a battery switch that would be ideal in this situation, and the switch has positions for OFF (both batteries disconnected), BOTH (both batteries connected), 1 (only one battery connected), and 2 (the other battery connected).

Its not really something I see much in RVs, but they are very common in dual battery boat setups. The only issue is the battery must be connected to keep it charged, so if the switch is in the OFF, 1, or 2 position, one or both batteries will not be connected to the charger.

But say you want to charge your batteries once a month in the winter, simply put the switch to BOTH and plug your coach into AC so the charger becomes operational. Once you are finished charging, unplug AC and put the battery switch back to OFF.

The 1, and 2 positions would probably not be used much - unless you have discovered a bad battery during a camping trip and want to isolate it. The primary reason for the 1 and 2 positions are for boats so that they can keep a fully charged battery disconnected in reserve. That way, if they drain the battery down, they can flip over to the other battery and start the engine.

However, since RV coaches don't normally start engines with the house batteries, these positions might not be used much.

[JamieGeek]

Originally Posted by Rlaugh

can you tell me does the knife disconnect get connected to the negative post, or can it be connected to the positive side.

Originally Posted by FW28z

I see no real reason the knife switch has to be on the negative side, other than a possible safety issue. If the knife switch was on the positive side, it might make contact with a part of the metal chassis that is connected to the negative side when switched off.

The posts are different sizes and the knife switch only fits on the negative post.

[blw2]

I personally don't like the look of those knife switches..... too much unprotected conductor for my liking.... and too much "throw dimension"

That's why I went with the screw top style. So far so good with them.

Just a personal opinion thing, no engineering basis for it.... I just like things somewhat neat and tidy.

I would have prefered the marine type disconnect (or industrial panel mount type, which are similar), but there's a significant cost differential there...

[FW28z]

Originally Posted by JamieGeek

The posts are different sizes and the knife switch only fits on the negative post.

True, if it is the tapered stud type.

Some deep-cycle posts are thumbscrews, and some are combo.