Electrical gremlin

[John Suter]

Hi David,

> I have a slight problem with my generator auto
> start feature. The auto start is controlled by a
> board called the Gencon, built by Westhaver
> Assoc. The gencon monitors the house batteries
> and the shore power and starts the generator
> when the house batteries dip below 11.4V or
> when the shore-power drops below 104V AC.

Let's start by eliminating:
If you have an incorrect AC adapter, the brownout
function will have the wrong threshold. Your '02
(actually Gencons made after 98) are typically
calibrated for the radio Shack AC adapter catalog
number 273-1764 and the Adapt-a-plug (Radio shack #
273-1708 attached so the plug tip is the positive.

> I have good shore power and my house batteries
> are charged, the dash "DC Volts Coach" gauge
> reads 14V and the trace inverters indicate 100%
> charge, nonetheless the gencon wants to start the
> generator.

A reading above 12.65V means the batteries are not
"at rest" (one hour or more without charging or
discharging) such that what is being "read" is likely
the float/maintenance, inverter/charging voltage
provided to the coach/house battery bank(sometimes
called the surface charge), and not necessarily that
of the battery bank itself.

> Here's the kicker, my dash "DC Volts Engine"
> gauge reads around 12.5V,

When the "Aux Battery" switch (sometimes called the
boost switch) is "off" and the engine ignition switch
also "off," an isolation solenoid separates the engine
battery bank from the coach/house battery bank. This
12.5V is the 12.65 or so, referred to previously as
the "resting voltage." Your 12.5v tends to indicate a
"good" battery bank. 12.0 would indicate discharged.
For the record, when the ignition switch is "on" the
solenoid is typically energized so the engine
alternator will charge all banks (note the green LED
at the dash switch).

> if I switch the dash
> "Aux Battery" switch to "on " (thereby connecting
> the house and the engine batteries), the gencon
> no longer wants to start the generator.
>
> I would think that the discharged

(Incorrect assumption about discharged)

engine batteries
> would put even more of a load on the house batteries
> prompting the gencon to start the generator, but the
> reverse happens, with the "Aux Battery" switch
> disabled the
> gencon wants to start the generator while enabling
> the "Aux Battery" switch prevents the gencon from
> starting the generator. It's almost as if my gencon
> is
> monitoring the engine batteries and not the house
> batteries...

It is possible an error was made or a change
somewhere along the way. How long has this been
happening and were there any changes made to the
batteries, inverter/charger, switches in the bays,
etc.?

Have you noticed the switch in the forward-most,
driver-side bin, labeled "No 110V A/C and Low 110V
A/c" or words to that effect?
That switch enables/disables the brown-out "shore
power" sensing. In "Low" mode the brown-out feature
is enabled. In the other position, nothing will
happen with no shore power unless the house bank is
also below 11.25V - PROVIDING, the selectable voltages
are properly set on the plug-in Radio Shack device
which you will find plugged into the 110V duplex
outlet high, in the bay.

> Thanks for your help,
> David Brady
> '02 LXi, Smokey
> Va

Let's start with the above and see where we can go
from here to solve the problem.

John Suter
2000LXi and prior PT40's


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