Auto Battery problems....

[kzener40]

I continue to have a problem with keeping my auto battery fully charged on my 1984 310 MH, even though it's new and has been checked to make sure it's not the problem. For some reason I can't seem to keep my auto battery in the fully charged range. After just a few days of sitting my control panel shows the battery is "fair to weak". In my manual it refers to a switch located in my glove box that will connect all 3 batteries when starting the MH. Here's what it says,"a manual push button switch provided in the glove box will close the solenoid when depressed and allow you to start the vehicle from the coach batteries" I have scoured the glove box and no such switch exists. Most MH mechanics tell me there has to be such a switch somewhere but can't find it.

Does anyone have any ideas on what may be draining my main battery? How about that elusive switch?

Thanks
Ken

[thenewkid64]

I have this problem on my MH and I belive it is form a PO installed electric step. If I leave the MH with the batteries connected then I have a problem maintaining a charge on the starter batttery. The house battery seem fine. The only draw I can come up with is the step. I have rewired the batteries and installed cutout switches. If I disconnect the starting battery the only coach option that does not work is the step. I have not been able to figure out a way, even with the wiring diagram from kwikee, how to disconnect the step fully from the starting battery. My reccomendation is to dissconect the starting battery and see what stops working. You may also want to test your battery isolator as it could have gone bad and be draining the battery.

Good luck, and be careful. 12V is just as dangerous as 120V.

[ALANSD]

My motorhome has a dash mounted swithch that reads "starter assist" and will connect the batteries together in the event the auto one is too weak.
I also noticed that I get a fair or poor reading on the AS panel gauge (light) when I am plugged in to shore power or generator is on, then it reads good when disconnected from those a/c sources.
You might start up the motor, and put your volt meter on the various poles of the battery isolator, and check the readings. At times mine read the sum of the 3 batteries together, as if the alternator was not putting out correctly, then when I repaired a wire, and replaced the alternator (which might not have been bad after all), the readings were correct. The numbers ranged from 14- 28 or higher volts before until I replaced that starter ignition wire that was mostly burnt. It was amazing what that one bad connection would do. It was burnt at the end right near the solenoid. Hanging on by a thin thread .
Does your coach not want to start from the auto battery alone? I would also check that starter ignition wire near the solenoid, as mine was doing the very same thing, ocasionally not wanting to start at all. Just a shot....

[Paul Daugherty]

You might want to check the reverse current diode on the generator. If it is open it will drain your start battery. Now, don't ask me how to check it, I just remember reading that when working on my generator. Also, if you know where your ground is for the engine make sure its clean tight and pure.
Hope that helps
Paul....

[thenewkid64]

Finding it is the going to be the hardest part. Testing it should be easy. If I remeber my electronics, a diode only works 1 way. Using a ohm meter you should only get continuity one way. if you switch the probes you should not have continuity in both directions. This assumes that the diode is not installed in the system and is loose. If it is installed and is designed to stop the generator form draining th battery is should have 12 volts on only 1 side of the diode. Now that I have competely confused everone I will try to test mine and tell you what I find.

[Pick]

You could disconnect the charge line from the alternator for a few days, that would isolate it.

[Paul Daugherty]

You are right about the one direction of current flow. But when you check it the resistance should be zero right? If you check one end of a wire to the other the probe should read zero because you are not losing anything. I would send you a copy of my book that has a wiring schematic for the generator but it is with the generator at the moment.

Paul...

[thenewkid64]

Paul,

Depending on the polarity of the probes on the meter you should have an open one way and continuity the other. This assumes the meter uses enough voltage to cause the diode to close/open.

I have not gotten out to the MH to check it, My better half asked me to build some furniture and sent me to the lumber yard. I hate it when she asks me to use my power tools.

[winner]

With reference to discharging battery, I have the same problem on my MH. We finally traced the problem to the Electric Step.
Mine is a Kwikee, and according to them, parts are not available for it - If I want to fix the problem, there is a conversion kit available, but at $320 - it iwas easier for my mechanic to install a very simple switch on the battery cable that I turn off, along with the kill switch when I leave the coach. The problem is in the electronic control unit of the step - there is a diode that goes to ground.

[Paul Daugherty]

Hey Brett,

Sorry you have to use your power tools

Paul..

[Larry Brown]

In later model delco remy alts with internal voltage regulators thare 3 rectifirers that act as diodes. these are known to go bad if some one gets the booster cables wrong during a jump start are if the rigs touch bumpers during jumps. if one blows it will cause the battery to drain.(bleed back the other way). So if your couch checks out ok. have the alt tested because it can still charge under this condition. you can buy just the regulator and its not to bad to change. I f you look on the back of the alt at the top by the main power terminal the is a small hole and you can use a tooth pick to hold the brushes during dissasembly and assemby.