generator battery not holding or being charged?

[krminyl@...]

John,

This is what I sent to John Ely a few days ago about some problems he was
having with his genset battery not charging....the only thing I'll add
additionally is that there is a solenoid (starter type) underneath the coach's
air
step, left side, mounted on the fenderwell to the front of the curbside front
wheel. This is the solenoid that, when the "aux battery" dash switch is
pressed, ties the coach's house batteries and the getset battery together. I
burned my solenoid up messing with the system. This particular solenoid works
off the "power to ground" principal (my term I think), meaning that the
solenoid activates by completing the circuitry by grounding the circuit, not by
applying +12V power (similar to a horn relay circuit). Took me a while to
figure
that one out.

I'd replace the diode (described below in the other email I sent...if your
model coach has one), then the aux batt solenoid, Make sure you have a good,
charged genset battery once the repairs are completed. A final
recommendation...make sure your batteries are disconnected when you start
screwing with
the solenoids...lots of amperage (albeit 12v), but it can quickly arc a wrench
or screwdriver to a terminal or frame part rather quickly and with a lot of
sparks and noise (unfortunately, learned from experience). Not a good thing
when working in close quarters, upside down, if you catch my drift.

Best of luck....

Kevin McKeown
Yorba Linda, CA
1986 38' PT

What I sent to John Ely......

Hi John,

I chased the same gremlin for a few years before I finally fixed the
problem. Prior to fixing it, I used to put a little 110v battery charger on
the
genset battery while camping, and that took care of the problem temporarily.

To fix mine, I replaced most of the "guts" inside the compartment where your
battery chargers are. I believe the real culprit was a large diode,
Bluebird's engineering at that time, to keep the current flowing TO the genset
battery not from it. The diode is a stud mounted component, with a heavy
(maybe 8
or 10 ga) wire in each end. One end of the diode has a stud with an eye in
the end, and the wire soldered to it. The other end is insulated, and
accepts a wire lug. It has a threaded shaft, and is typically screwed in a
aluminum plate inside the compartment. I also replaced the little self-reset
breakers, the solenoids, and some of the old wiring that came with the bus (in
the
battery charger compartment).

Keep in mind that the genset battery will charge slightly at a lower voltage
than the house batteries...this is due to the minor voltage drop caused by
the rectifier (diode) ...about a half a volt. Mine reads around 13.6v when
the genset is running, and the house batteries around 14v or so. My
recommendation is to change the diode first, and see it that fixes the
problem...it's
about a $10 part.

Let us know if it fixes it...I think it will. If you need some pictures,
let me know.

Kevin McKeown
Yorba Linda, CA
1986 38' PT



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