Instruction Manual

33
Before beginning to record you may wish to erase all the data recorded in the past using (Program
number P45), although it is not necessary to do this in order to “make space” for the data. When the
memory is full new data is still recorded by overwriting the oldest data.
Size of memory: Data will be recorded until the memory is filled--after which the oldest data will
gradually be overwritten with new data. To estimate the number of data points in the memory use the
formula:
First compute 61[3 + (2  p)].
where p=# of items measured at each measurement time. (1-8)
Keep only the integer part. (throw away the fraction). Then multiply by 116. This tells how many times
all the data can be recorded before the oldest data will begin to be overwritten. If only one item is
being recorded you can record 1392 times. If all 8 are being recorded you can record 348. Divide by
the number of measurements per day to determine number of days.
6.C.2: Battery discharge profile Logged Data:
Program Modes affecting data: P14, P15, P32, P33, P43, P46 .
This function is intended to provide data that can show if the battery system is losing capacity. It does
so by recording (filtered) “volts” and “amps” as the battery is gradually discharged or charged. It
records these every time the discharge “state of charge” drops by 5% (or 10% if you so choose).
Typically, starting from fully charged, as a good battery discharges, the “volts” will drop only slowly at
first. At some level of % discharge however, this voltage will begin to drop more rapidly as the
batteries begin to exhaust their energy. As the battery ages, or if possibly a cell or battery connection
becomes weak, this voltage decline will occur at higher percentage of charge. (This level of voltage
will also be influenced somewhat by the current draw—which is why “Amps” are simultaneously
recorded.) If voltage begins to drop more rapidly at an unexpectedly high “state of charge”, this could
alert you to a battery bank that may soon fail. Typically one would observe the voltage data for
successive charge/discharge cycles, particularly observing when the battery is at lowest state of
charge. If over successive charge/discharge cycles this minimum voltage begins to drop (for a given %
of charge) that could anticipate a battery system failure.
To record this data you must set up Program Mode 43 which allows you to choose whether the
data is collected for every 5% or 10% change in “state of charge” as indicated by AD 22, AD23
(Battery Percent full). You may choose to record from battery bank 1, or bank 2, or both. Other
program modes affecting the data are P14 and P15 (Battery capacity). This specifies the “reference”
100% full capacity, and so thus calibrates the amount of “amp hours” represented by each 5%
additional discharge. You can determine the number of “amp hours” each 5% interval represents by
multiplying the value in P14 (or P15) by 5%.
Before beginning you may wish to erase all the data recorded in the past using (Program P46). This
is not necessary to “make space”, however. When full the oldest data in memory will be gradually be
overwritten by the newest.
To view the data using the PentaMetric Display unit, use the “Battery discharge profile display mode
(“BH”). See section 4.A.3. This data may be particularly useful using the computer interface, because
it is easier to use the computer to graph (and analyze) the data, comparing it with past discharge
profiles to identify a trend that would point to future capacity failure. In addition, the computer will show
the days (but not the time) when the data was recorded.
Size of memory: It records a maximum of 744 data points, after which it will write over the oldest data
first. For example, if the batteries go through one cycle per day, and go from 100% to 48% each day,
and if data is collected every 5%, the system would record usually 11 events while being discharged,
and 11 events while being charged, for a total of 22 per day. (This number could be higher if during
discharge the batteries are partially charged again, causing an extra “5%” boundary point to be
crossed again, after which further discharge occurs.) If one battery is being monitored it would monitor
about 33 days before overwriting the old data.