On Tue, 14 Jun 2005 18:11:11 -0700, ContestID67 wrote:

2) Use two batteries with an A/B switch. This requires the recorder to
be able to survive the failure until you flip the switch. Some can
handle short power outages, others cannot. I have no test data to
suggest how long of an outage they can handle while a good battery is
switched in.

We installed two batteries with changeover switches, so we have a warning
when one battery is flat (like a the reserve tap on a motorbike fuel tank).

But our Volkslogger runs off a separate circuit which is connected to both
batteries via low voltage drop electronic diodes. It draws current from
which ever battery has the highest voltage.

I have tested it and cannot reset the Volkslogger without unplugging both
batteries. (But I can measure the battery voltage on any one battery with
the VL battery test function simply by unplugging the other. The voltage
reading is that after the diode loss, slightly less than what the rest of
the panel sees - unfortunately I can only do this on the ground)


Ian