On Feb 19, 10:56*pm, GeoLane at PTD dot NET GeoLane at PTD dot NET
wrote:
On Fri, 18 Feb 2011 08:24:41 -0800 (PST), Jim Wilkins

wrote:
Yup. With the engine off, the battery reads something like 13.6V
freshly charged, and once the engine's running the voltage across the
battery terminals is 16+V
...
RWL

Try a known-good battery.

The battery is brand new and I charged it before attaching it to the
generator.

RWL

Give the freshly charged battery a day's rest for the surface charge
to dissipate, then it should measure 12.6 to 12.8V. You could
discharge it to 12.0V and then check the charging voltage.

I opened a Harbor Freight $3 multimeter with a blown 0.5A current fuse
and found a calibration pot, so I set up an adjustable 12.000V
reference and calibrated some meters. The pot is quite sensitive but
can be set so the meter alternates between 11.99 and 12.00 within
about 5mV of 12.000V. I marked the pots before turning them and can
barely see a difference. So far the worst one was off by 0.05V before
adjustment.

One yellow meter reads the same with a fresh or discharged 9V battery.
The battery connectors are too flimsy to risk testing all of them

jsw