PN# 500-10100
Page 2
Rev. D, 06/11
FIG. 1 BATTERY PACK SELECTION
MIN
1 HR
2 HR
4 HR
8 HR
16 HR
24 HR
48 HR
72 HR
UL STD.
150 MA
300 MA
500 MA
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
4 AH
8 AH
8 AH
8 AH
12 AH
12 AH
8 AH
8 AH
12 AH
12 AH
16 AH
16 AH
N/A
BACKUP TIME DESIRED
"MIN" TIME REFERS TO FACILITY USING EMERGENCY GENERATOR WHERE THE
BATTERIES ARE ONLY REQUIRED TO OPERATE THE SYSTEM
FOR UNDER 3 MINUTES UNTIL THE GENERATOR TAKES OVER
U.L. STANDARD REQUIRES 4 HOURS OF BATTERY OPERATION FOLLOWED BY
A 24 HOUR RECHARGE PERIOD AND THEN A SECOND 4 HOURS OF OPERATION
BATTERIES MUST BE SEALED LEAD ACID OR GEL CELL TYPES.
DRY CELLS WILL NOT RECHARGE AND WILL BE DAMAGED.
THIS CHART IS ONLY VALID IF BATTERIES ARE OPERATED
AT ROOM TEMPERATURE. IN A COLD ENVIRONMENT, CAPACITY IS REDUCED.
BATTERIES SHOULD BE REPLACED AFTER 5 YEARS OF USE.
750 MA
12 AH
16 AH
20 AH
CUR
RENT
DR
A
W
N
CHART TO DETERMINE SIZE OF BATTERY PACK
N/A
N/A
N/A
N/A
The components utilized on the unit for battery charging function for battery packs up to 20 amp
hours in capacity whether 12 or 24 volts. Note that certain long backup times are not
achievable with the maximum size of the battery packs (“N/A” appears in the chart). Consult
the battery pack chart to calculate the correct battery pack based on desired backup time and
the current drawn by the load. Note that for proper battery charging the power supply
must be set at 27 volts in the case of a 24 volt system, and 13.5 volts in the case of a 12
volt system. Securitron power supplies are capable of this adjustment and if it is not made,
the batteries will not hold their full capacity nor their normal operating life, and may be
damaged. Also note that batteries must be replaced at least every 5 years as that is
their maximum operating life.
3.4 CIRCUIT POLYSWITCHES AND FUSING
A 1 Amp AC fuse is on the board together with a 2.5 Amp DC Polyswitch for the BPS series.
The AC fuse is on the hot 120 VAC input and protects against a transformer internal short. A
short in the DC load will not blow the AC fuse as the power supply is short-circuit protected. If
more than its rated output is attempted to be drawn, it will shut off.
A DC short, therefore, cannot damage the power supply but still will cause problems as the load
will be shut off. Additionally, if batteries are used, they will switch into the short when the
power supply shuts down and will supply a tremendous amount of current into a short which is
easily capable of melting wire insulation. To protect against a short circuit when batteries are
being employed, a 2.5 Amp DC Polyswitch breaker is provided. The Polyswitch functions as
an automatic circuit breaker. If it receives an overload, it rapidly cuts the current down to a
small leakage current (about 100 mA). If this happens there is a reset procedure. All
current must be removed from the Polyswitch for a period of 10 seconds. You do this by
simply disconnecting the wire from the “+” or “-” terminal. If, for example, a short circuit
appeared which tripped the Polyswitch and you corrected the short but did not disconnect the
wire from the “-” terminal, the Polyswitch would “see” the normal load and would continue to
block current flow until reset in the manner just described.
