CruzPro SAR-20 Smart Alternator Regulator

The SAR20 Smart Alternator Regulator turbo-charges your charging
system by swapping your fixed voltage regulator with a high
performance multi-step Smart Alternator Regulator (SAR).

P type alternators up to 160 amps (8 amp maximum field winding
current).

Fixed voltage regulators are inexpensive to manufacture but are
a poor trade-off between cost and performance for the boat owner.
The initial savings are soon offset by the requirement to run the
engine longer to achieve the same charge, battery life, noise, heat
and smell generated by the engine. A fixed voltage regulator will
also overcharge your batteries on longer runs – reducing their life
and requiring more frequent top-ups of water.

The CruzPro SAR20 enables you to safely fast charge your boat
batteries thereby greatly reducing engine run time.

The SAR20 is a multi-step charge controller that commands
maximum safe output from your alternator while monitoring battery
voltage and temperature. The SAR20 will deliver the bulk of the
battery charge at maximum alternator output allowing battery
voltage to rise until the inchabsorption voltageinch has been
reached. The SAR then lowers the alternator output to maintain a
constant battery voltage at the absorption point. The absorption
voltage is maintained for a period of time dependent SAR20 cuts
back the battery voltage to a safe inchfloatinch voltage.

The SAR20 will also enable you to desulfate your battery plates
by enabling an inchequalization cycleinch. During equalization the
SAR20 slowly raises battery voltage to an equalization level while
limiting the charge current to about 4-6% of your battery’s
amp-hour capacity. This safely dissolves the sulfates that form on
the battery plates during discharge and extends battery life.

The correct absorption, float and equalization voltages are
dependent upon temperature and battery chemistry. The higher the
temperature the lower values of absorption, float and equalization
voltages that must be used to optimize battery life. For this
reason a remote sensor is used by SAR20 to monitor battery
temperature and adjust the voltages accordingly. The SAR20 also has
some programming switches inside to tell it what type of battery
you are using and further adjust the charging voltages accordingly.
Your fixed voltage regulator knows nothing about battery
temperature and will almost always be charging to the wrong
value.

Another handy feature of the SAR20 is a trouble-shooting LED
that tells you what it’s doing. The LED will blink in various
combinations to tell you what stage the SAR20 is in (bulk,
absorption, float, equalization). The SAR20 can be set for either
12 and 24 volt alternators.

Specifications:

• Operating Voltage: 9.5 to 30.0 VDC, 0.02 amps nominal.
• Operating temperature: 0 to 50 deg Celsius ( 32 to 122 deg
  Fahrenheit).
• Size: 100 x 60 x 30 mm (4 x 2.4 x 1.2 inch).
• Built-in LED indicator blinks: Once/sec for bulk stage.
  Twice/sec for absorption stage. Three/sec for float stage.
  Continuously during equalization stage.
• Temperature compensation: Comes with remote temperature sensor
  that compensates all four stages for battery temperature.
• Accuracy: Remote battery voltage sensing compensates for line
  drops, line resistance, switch resistance, isolator diode drops,
  etc.
• Drive Capability: P type alternators up to 160 amps (8 amp
  maximum field winding current).

Connection Diagram:

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