The photograph on the previous page shows a bench unit for testing 25-cell 7AH battery packs.
Other arrangements are available to order, this case size will allow up to 35 cells to be tested and charged.
The cycling charger operates by discharging the battery on test down to 1.00V per cell,
then recharging the battery to full capacity in a timed recharge. The CD44 uses this cycle
twice, once to ensure that the battery on test is fully charged, followed by a second
cycle which first checks the battery capacity under constant current discharge conditions,
and then recharges the battery ready for use. The display shows the removed capacity as
the battery discharges, the reading being held at the end of the test, to enable logging
of data to take place if required.
The module illustrated uses our own bench case, with connection to the battery by flying lead.
Lead-Acid batteries can be cycled on the system in the same way as Nickel-Cadmium types.
No special arrangements are required, but as the rated capacity of most lead-acid
batteries is at the 20 hour rate, the total cycle time could become very extended.
© Prepair Ltd 1990-2005 E&OE
TECHNICAL DESCRIPTION.
The CD44 system comprises a cycling true constant-current nickel-cadmium charger, a
control logic section, a load resistance and a digital display, which can be of the LED or LCD type.
CYCLE TIMING
The system typically requires a time of 15-20 hours for the complete cycle. This is
calculated for a fully charged battery being put on test. A fully discharged battery would
not go through the initial discharge portion of the first cycle, but would go straight to
the first recharge. The discharge current and timing is based upon the standard 5 hour
rating of sealed Nickel-Cadmium batteries, the recharge time is usually in the order of 4-
5 hours, with a cooling period available between the first recharge and the start of
testing if required. At the end of the cycle, the battery is put on trickle charge.
CONSTRUCTION
The system is built around three printed circuit boards, the charger board, logic board and
either of two display boards, CD44 LED and CD44 LCD. The display boards are panel mounting
and are interchangeable without adjustment. All PCB's are high quality double sided plated
through hole types, with heavy duty connectors for all signal and power connections. All
PCB's and transformers are designed, manufactured and assembled by Prepair.
POWER SUPPLY
The charger has its own built in power supply, the unit runs from standard AC mains voltages,
with adjustable input available to suit 110/220/240V 50/60Hz.
BATTERY TYPES AND CAPACITIES
The CD44 system is configurable to suit most battery types and voltages. There are practical
limits to the size of battery that can be tested, but most batteries used for
telecommunications, portable equipment etc can be tested. The CD44 is not multi-range,ie
it will not test more than one type, it is configured for one battery voltage and capacity
only.
TEST RESULTS.
The CD44 produces capacity figures in the form of a digital display. The results obtained
from the unit can be interpreted by trend, to show battery performance and capacity over a
period. Battery faults such as failed cells, broken internal links etc can be shown up
immediately in the test results. By logging the results, battery life can be checked to
show deterioration and under-performance. Automatic data logging is not available at
present, but is being considered as a future upgrade. Data loggers are used on the newer
rail battery tester, also in this section of the website.
TYPICAL USERS
The CD44 is used in telecommunications, mobile 'phone and walkie-talkie servicing
establishments, portable electronic equipment manufacturers and where accurate battery
capacity information is essential.
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