Jim Altman has been asking a slight negative charge condition when he drives
with his headlights on.
Both of my TR4's act in this manner. I have noticed that if you run the
lights for extended periods (four or more hours) that the gauge will come back
to the neutral position. I had always assumed that this condition was normal
untill I refurbished and adjusted my control box exactly as the repair manual
indicates. Now it varies very little from the neutral position once the
battery has had a chance to recharge from starting. It will discharge
momentarily when any electrical accessory is activated but I think that this
is due to the fact that it takes a split second for the control box to react
the increased load. It will discharge at idle when the lights are on as the
generator needs at least 2,000 engine rpm's to reach its rated capacity.
My feeling is that the system runs at a slightly higher voltage under minimal
load. This brings the battery to to a slightly higher voltage. When the
system is under load it runs at a slightly lower voltage and the battery will
slowly discharge till it reaches the system voltage.. With the control box
exactly to spec this difference is very slight and is just noticable. I ran
with the system showing 1 or 2 amps discharge with the lights on for about 20
years and never had a proplem so I do not think that I would worry too much
about it.
One note, if you do adjust the control box use a analog voltage meter as a
digital one will give you false readings. DO NOT USE SANDPAPER TO CLEAN THE
CONTACTS. I wound up with a micro grain of sand embedded in the contacts that
caused all sorts of stange conditions till I figured it out.
John Hamer
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