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Ian – I believe
that Jeff sees support so we should see a response shortly. Can anyone other than Jeff give an
update on this? Any idea when CE
will be available. This will be a
certification issue. We must get
to a point where software is stable and not undergoing these constant changes if
we ever expect to have products certified. Larry J. Dix -----Original
Message----- See below. -----Original
Message----- Johnson County, KS has received 6 AVTS
units for demonstration purposes. One of the units says Low for
the Battery Status instead of Charging, this unit has been plugged in
since they received it, over a week now. Does this mean that the
battery is bad, or that the indication of the battery does not work??? Windows CE 2.12 has a bug where it always
reports the Main Backup Battery as a "Low" Status. This is
apparently corrected in Windows CE 3.0. A PIC microcontroller is
used to control battery charging/discharging and power distribution. The
PIC monitors the battery and reports a percentage of the battery's charge
capacity to WinCE, but at this time, the BallotStation software doesn't
use the Battery Charge Capacity Percentage, only the status word (i.e.,
good, low, very low.) And WinCE 2.12 is stuck on "low". I
don't know the outlook for implementing WinCE 3.0. Jeff Dean would be the
person to make an inquiry to on that matter. They are in the planning stages of their
warehouse, and would like to know what our recommendations are for charging of
the AVTS units. Do the AVTS units need to be plugged in continously??? No, they don't need to be
plugged in continuously. However, they can if they wish. It
won't harm the unit. Can the AVTS units need to
be charged on a rotation schedule??? If it is
logistically more feasible for the warehouse staff to use a rotation schedule,
then they can do that. The battery charging circuit only needs AC
power attached to charge the battery. With the unit turned off and
AC applied, the system will be in slow charge mode and will only draw a small
amount of AC power (0.1A @ 110VAC). At that small of a current
consumption, quite a few units can be attached to a single circuit. NOTE: Sealed lead
acid batteries lose approximately 3% of their charge per month just sitting on
the shelf. If left unused, they should be recharged a minimum of
once a year. Preferable would be once every six months.
Obviously, if they have more frequent elections cycles, and the units are
charged before and after each cycle, this minimum wouldn't be a concern.
But if they have spare units that are always held in reserve and never used,
then they should meet the minimum charging requirements. Do the AVTS units need to be
charged only 24 hours before an election??? On slow charge, a
discharged battery will be charged in 12 hours. With AC applied and the
unit is turned on and operational, the charging circuit switches into fast
charge mode. This mode will bring a discharged battery to 85% of
full charge within 3 hours. This is done by applying the
manufacturer's maximum recommended charge current into the battery. The
system will switch to slow charge after reaching the 85% point. Fast
charging past that point can reduce the battery's life expectancy. The
purpose behind the fast charge mode is to maximum charge time in a rolling
blackout situation. When the unit is using
fast charge mode, it will consume more AC power ( 0.3A @ 110VAC). NOTE: The ballot
station operation takes priority over the charging of the battery. If the
ballot station operation needs to draw power that nears the capacity of the
power supply (e.g, someone plugs in an unapproved PCMCIA device that sucks the
power down), then the battery charging circuit will either reduce to slow
charge mode or stop charging in favor of the ballot station load
requirements.. I will be going down to Johnson County,
KS on Tuesday for an all paper election, and they would like to know the
answers to these questions. Currently, an idle
system will take 5-1/2 hours to discharge a fully charged battery. This
is with the LCD panel displaying constantly. If the software is
developed with a sleep mode for the LCD panel, this discharge time could be
considerably longer. The LCD panel and its backlighting draw the most
power. The tested configuration
for the 5-1/2 hour discharge time used a 32MB flash memory card as the
only PCMCIA device. Other PCMCIA devices would draw additional power and
therefore shorten the discharge time. Printing a paper tape on
battery power draws considerable power, but that is cyclical and not a concern
for overall discharge time. Unless, of course, it is done continuously. On discharge, when the
monitored battery voltage reaches 10.5V, the system will automatically
shutdown. This is the 0% capacity point. Some components in the
system require a minimum of 10.2V for operation and the life expectancy of a
sealed lead acid battery will be reduced if it is used below 10.5V.
Life expectancy on sealed lead acid batteries is 5 years. I hope that answers your
questions on battery charging (and discharging). Let me know if you
need anything further. Ian |