Asus A636N PDA and Gomadic power adapter/holder crashes PDA

Hi,

This is sort of GPS related so I thought I'd give it a shot:

Last year I bought a Gomadic powered PDA holder for use with my Asus
A636N PDA/GPS unit, it worked great all last summer in my Triumph TR3.

This spring I used it again and after an hour (5 minutes into return
trip) the Asus unit shut down, restart it and it would either shutdown
again or Windows mobile 6 would crash after only a couple of
minutes. I've the same combination in another car (briefly) and with
the Asus cig adapter in a 3rd car and it works fine.

The Triumph is 12v positive ground but I've reversed the connections
to the cig lighter and confirmed with a multi-meter that I have the
right polarity at the lighter. However the car does have a generator
instead of a modern alternator, that means a) the voltage fluctuates
more then a modern car (I observed as high as 16.5 volts) and b) it
might have more noise/interference etc.. coming to the lighter.

Gomadic assures me that the voltage shouldn't be a problem for their
unit but they can't comment on what the noise may or may not do to the
charging circuitry of the PDA. A buddy suggested a noise filter for
the cig power circuit from a car audio store.

Anybody here old enough to comment on generators and modern
electronics ;)

Thanks,

Art