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Sentinel 150 Series Battery Chargers

The Sentinel 150 line are highly efficient, high performance battery chargers, designed for continuous float charge and standby power applications. Switch mode technology provides major advances in power supply and battery charger design, giving a compact and lightweight construction, improved efficiency and low heat dissipation, wide supply voltage tolerance and low output ripple.

murphy sentinel 150 battery charger


The chargers are configured for fast, accurate charging, to give optimum battery life and reliability. The very smooth output (< 1% ripple) allows charging of sealed or vented batteries – e.g. Nickel Cadmium (NiCd), Lead Acid sealed (VRLA), vented and Planté cells – or use as a stand-alone power supply. Factory calibration is optimized for each specific battery type. All models features an intelligent, multi-stage charge regime: during charge recovery mode, the Sentinel gives a constant (maximum) current output; as the battery approaches peak charge, the output reverts to float charge mode, maintaining an optimum cell voltage and supplying additional standing load current up to the rated maximum. Output current is always limited to the rated maximum, even during high load (e.g. engine cranking), short-circuit or reverse polarity connection.

Standard Sentinel 150 Charging Features:

•  Switch mode power supply technology: light and compact, power efficient with low heat dissipation
•  High rate, low ripple float charging: 5 or 10A@ 12 VDC, 5A @ 24 VDC
•  AutoBoost and temperature compensation
•  For stationary engine, genset and standby power applications
•  UL, CSA and CE compliant
•  High quality stainless steel case
•  NFPA model with alarms for AC failure, charge fail, high battery volts, low battery volts


Power supply
Operating voltage:  95 – 250 VAC
Operating frequency:  47 – 63 Hz.

DC Charge Output
Nominal voltage:  programmable 12 or 24 VDC
Float/boost voltage:  programmable (see panel 5: "Output Calibration")
Maximum current limit:  5 A (12 and 24V models) or 10 A (12V models)
Voltage ripple:  < 1%
Line regulation:  < 2%
Load regulation:  < 2%

Alarm outputs
Charge fail, mains AC fail:  1 x solid state relay, + DC during normal charge, open circuit during fault
High and low battery voltage (ESNTLUL1501210xx NFPA only):  2 x solid state relays, dry/volt-free contacts, closed on fault
Current rating (all relay outputs): 250mA max @ 30 VDC (resistive load), UL class 2

Operating temperature:  -40° to +140°F / -20° to +60°C
Humidity:  20% to 90% RH
Dimensions:  see panels 3 & 4 "Dimensions"
Weight:  see panels 3 & 4 "Dimensions"
Electrical safety:  2006/95/EC
Electromagnetic compatibility:  2004/108/EC, (EN 61000-6-2, EN 61000-6-4)

UL approvals
All standard (E)SNTLUL150 models:  BBGQ: UL1236, CSA22.2 no. 107.2
ESNTLUL1501210xxNFPA models only:  BBHH: UL1236 SE

murphy sentinel 150 electrical diagram

1) AC input fusing (F1). All UL-approved 150 models include a replaceable, circuit-board mount TR5 fuse package. See charger label for fuse rating.
2) DC fusing (F2): all UL 150 models include an internal, electronic (self-resetting) output fuse.
3) battery output is isolated from chassis.
4) charge fail / mains AC fail alarm relay shown in de-energized (powered down) state.
5) high and low battery voltage alarm outputs (enclosed NFPA version only) not shown
6) on all UL 150 models, AC supply input ground/earth connection is by M4 chassis stud marked FG (frame ground).

Open-frame SNTLUL150xx

murphy sentinel 150 dimensional diagram

Optional clip for DIN rail mounting (2 required for each charger), Part # 045-0001

W     4.33 in. / 110 mm
H      5.31 in. / 135 mm
D      3.07 in. / 78 mm

Fixing holes:
X      3.94 in. / 100 mm
Y1    4.53 in. / 115 mm
Y2    2.26 in. / 57.5 mm

1.2 lb. / 0.55 kg

Dimensions for reference only. Use actual product for mounting template. For safe heat dissipation, mount product in orientation shown, with minimum air-gap clearance of 1.5 in./40mm above/below and 1.0 in./25mm at each side.

ESNTLUL150xx models

murphy sentinel 150 dimensional diagram

W       4.72 in. / 120 mm
H1      10.51 in. / 267 mm
H2      2.76 in. / 70 mm
D1      3.74 in. / 95 mm
D2      5.12 in. / 130 mm

Fixing holes:
X      2.50 in. / 63.5 mm
Y      10.04 in. / 255 mm

2.8 lb. / 1.25 kg

ESNTLUL150xx NFPA models

murphy sentinel 150 dimensional diagram

W       6.50 in. / 165mm
H1      11.81 in. / 300 mm
H2      3.15 in. / 80 mm
D1      4.92 in. / 125 mm
D2      5.12 in. / 130 mm

Fixing holes:
X      2.50 in. / 63.5 mm
Y      11.25 in. / 285.5 mm

5.0 lb. / 2.25 kg

Dimensions for reference only. Use actual product for mounting template. For safe heat dissipation, mount product in orientation shown, with minimum air-gap clearance of 1.5 in./40mm above/below and 1.0 in./25mm at each side.

murphy sentinel 150 output calibration diagram

Calibration figures at 20°C. If temperature compensation is enabled, and remote SNTL-RTC temperature sensor connected, output voltage automatically varies by 3mV per cell per 1°C deviation from 20°C, within the range –10° to +50°C. Increasing temperatures give decreasing outputs; decreasing temperatures give increasing outputs.

murphy sentinel 150 how to order diagram



AutoBoost provides a temporary increase in output voltage, equalising the charge between cells and maximising battery life and capacity. AutoBoost is triggered automatically when the battery falls below a preset voltage, or can be initiated manually through a momentary switch input. At the end of the AutoBoost cycle, Sentinel automatically reverts to normal float charge mode, preventing battery over-charge and gassing.

Temperature Compensation

The optimum charge voltage for lead acid and NiCd batteries varies with ambient temperature. Sentinel can be configured to sense battery temperature from a remote sensor and automatically compensate the output charge voltage.

Installation and Connection

UL-recognized SNTLUL150 model use an open-frame circuit board and base/heatsink with protective cover, for surface or DIN rail mounting in an existing control panel. UL-listed ESNTLUL150 models use a stainless-steel, wall-mounted case. Electrical connection is by screw-terminal blocks. Connection and cable access on ESNTL models is by a hinged front plate and knock-out sections in the enclosure side.


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