Low volts and amps; was alternator

[Jeff Miller]

Hindsight is 20/20 isn't it?

Granted the dash in your early '82 FC could have benefitted from the
addition of a few load-reduction relays: headlamps, ignition, A/C
switches for example. Fortunately BlueBird figured that out many
years ago also and made production changes.

Your alternator and wiring also ended in late '82, all of the 3208Ta
engines had the Leece-Neville alternator with internal regulator as
original equipment. The external voltage sense was retained, through
at least the late '90s S-60 powered WLWB coaches, and was intended to
maintain proper voltage at the power buss regardless of voltage drop
over the wiring run. Many alternator folks don't understand this
wiring and I usually see it mis-wired by now.

Although the charger wiring is long, 1AWG is probably considered
adequate for the original 90a peak charging current over perhaps 25'.
Some of the battery wiring was upsized in mid-CY-1982 with the
addition of the battery isolator next to the slide-out battery tray.

I'm not sure that 4/0 battery cables for the 18" from battery to
junction would be practical (or necessary). Perhaps a jump to 1/0
would be more manageable? Trying to use the slide-out battery tray
with 4/0 wires would be difficult and other than starting current
there isn't anything that normally will cause significant voltage
drop in that wiring.

- Jeff Miller


--- In WanderlodgeForum@yahoogroups.com, Tom Warner
wrote:
> FC models are saddled with two engineering design problems. The
first is
> that to much current is running thru the dash and the second is the
very
> long cables between the chargers, the alternator and the batteries.
The
> more current you can divert from the dash, such as using Bosch
relays for
> the lights, relays to get the A/C current(driver and passenger
sides) out
> of the dash, etc. Change the battery cables to 4/0 although not the
best
> fix nor the optimal condition, it does seem easier then to change
the
> chargers to the passenger front bin. One more problem is that the
FC models
> were designed to use the motorola alternator and an external
regulator that
> senses the voltage directly across the batteries. Most people have
changed
> that out to the Leece_Neville with the internal regulators which
cause a
> problem.
>
> Tom
> 1982 FC35
> Vernon Center,NY