Rig stops running at stops. Starts only with MOM switch pressed.

[Brave76]

I plugged in the Winnie (76 brave 440-3) last night to charge the batteries that have been neglected all winter. Then go to start it and nothing happens. Figure that the starting battery must not charge with the house batteries so I press the  mom. switch and it starts right up. I drive towards the freeway and at every light it dies but starts back up using the mom. Button on the dash. I also have the genny running thru all this so to not kill the house batteries too. So I get to the freeway and it runs just fine for the 20 miles on the freeway. Then I get to the back roads. Everytime I come to a stop the engine dies. I also notice the headlamps aren't working and it won't stay running. Sitting dead in the middle of the road with the generator running I figure out that if I hold the momentary switch down the headlights come on. So I hold it down for 5 minutes or so and it seems to kind of charge the chassis battery so I keep on going for about 5 minutes before it dies again and I have to start all over. After 4 or 5 cycles of this I get to the campground only 30 miles from home. yes I checked and the belt to the alternator is still in tact.

So my questions does this mean the Get in my friends car and go Get a batterry because the battery is toast,  does it mean call a tow truck cause the alternator is shot. How do I tell? Any tests to run? Also could I have ruined anything by my method to get here?

Thanks
Ben

[DaveVA78Chieftain]

Hi Ben,
Sorry to hear your not having a fun time.  Anyway, here is the scoop:

If you have a DUAL/NORM/MOM switch, the DUAL position does the same thing as the MOM position with the key ON.  After starting, just set to DUAL rather than holding it in MOM.  All it does is energize a constant voltage relay that cross connects the house and chassis battery so that the engine alternator can charge the house battery while charging the chassis battery.  MOM is for using the house battery assist the chassis battery for starting.

Unless you have upgraded your converter or have a seperate battery charger, the charger portion portion of the original converter is only around 6 amps so it is going to take a few days on either shore power or generator to try and charge a severly depleted battery using the original converter.  Let me say that again,  It is going to take a few days to recharge the battery using stock house setup.  Many do not understand that.

It is obvious that the chassis battery is completly depleted.  While batteries can sometimes be recovered they do not react well to being completly discharged and then sit the way for an extended period of time.  My first guess is going to be the chassis battery is toast.  If you have multiple house batteries, you could disconnect the current chassis battery and move one of the house batteries into it's place. A dead battery can harm the other batteries if left connected to the good batteries (DUAL/NORM/MOM switch).

The alternator will be putting out 13.8 - 14.5 volts at the battery when the engine is running.  If your trying to measue that with the original chassis battery in the system then make sure the switch is in DUAL and the generator is off.  You do not want to mistake the converter charger output for alternator output.  If the battery is toast, the alternator will not recharge it.  If you get a bad battery out of the system then the alternator can charge both the chassis and house system but with bad in the system it WILL drag the good batteries down with it.  If you do use a house battery as a temp solution, then use it only as a temp solution.  House battery is not made for starting applications (current draw to high).  Additionally, with known good batteries, start the engine and make sure the alternator is putting out 13.8 - 14.5 volts.  If not the the charging system also has problems.  Alternator or regulator (mounted to plate at rear of engine).

Also look at my charging section here:
http://dave78chieftain.zxq.net/

Dave

[Madathlon]

Only one small thing that you may missed, the reason you have the dieing at stop and not at hiway speeds is the Alt drops off line when you are at idle. THIS is common on older set up. Newer Computer run care have a aways on Alt, but older ones like the RV have a alt that shuts down at below 1000rpms, this is so it can cool better at low speeds due to the lack of air flow. Replace your starting batt and you be ok. of you like a always on alt you can use a older ford one or get a newer model once from a 85 or newer car/truck. this will give you a full time alt that will charge at idle RPMs

[tmackx]

Check your  battery connections for the chassis battery.  You can test this by grounding a test light on the neg terminal of the chassis battery.  Then check for voltage in the middle of the positive post vs the clamp around the post.  If you have a bad connection then you will get light from the test light in the middle of the post and nothing on the clamp.  Keep in mind it could be the neg connection too.