High Side Current Sensor
Installation and Operating Instructions

HSCS-12V and HSCS-24V October 10, 2001
Copyright ©1994 through 2001. All Rights Reserved - Ample Technology


The High Side Current Sensor, HSCS, is used in conjunction with the Energy Monitor, H1A to measure current in the positive rail, (high side) of the system. It can be used with alternators, battery chargers, solar panels and wind generators.

Models are available for 12 or 24 Volt systems.


The HSCS consists of a manganin shunt assembly that contains an embedded printed circuit board. The circuit consists of precision electronic parts connected in a novel manner to permit highly accurate and stable measurements of current in the positive rail. The measured signal is amplified and translated to an output signal that is referenced to the ground side of the power system.

Typical input is a differential 50 millivolts floating on the positive rail which results in an output of 2.5 Volts relative to the ground lead.

There are no adjustments necessary.

The circuit is potted in epoxy to protect the components from environmental insults. The circuit is very robust and can tolerate short term transients to 50 Volts.

Output Rating

The output should not be loaded other than that of the Energy Monitor, H1A. Any additional load will affect accuracy.

Signal Names and Functions

NOTE: There are three wires on the HSCS, Yellow, Black and Red. The Red wire is attached at the shunt assembly. The Yellow and Black wires must be connected to the Energy Monitor, H1A. Normally #16 AWG wire is sufficient for these wires.

Wiring Information

$\bullet$ Use pre-tinned wire :: Over time, corrosion attacks even the best connections. The use of pre-tinned wire will delay the onset of corrosion and is worth the slight price differential.

$\bullet$ Wire Size :: Wire gauge callouts on the drawings is only for reference. Always consult a wire table to determine what size is appropriate for your specific system. A wire table can be found in The Ample Power Primer, which can be ordered from an Ample Power dealer, or downloaded from the Ample Power website, http://www.amplepower.com.

$\bullet$ Wire Ground First :: Wire the Black first.

$\bullet$ Fuse at the Batteries :: Fuses are designed to prevent meltdown of wiring. To be effective, they must be located close to the power, whether that is battery positive, or positive distribution.

$\bullet$ Prevent Chafe :: Avoid running wires near metal objects, if possible. Always secure wires so that they cannot chafe with vibration.

Wiring Diagram


Troubleshooting Information

$\bullet$ Voltage to Operate :: A positive voltage is required on the HSCS Red wire to function. Note that the Black wire must be grounded.

Installation and Warranty Support

For questions regarding installation, operation, or warranty service contact PowerTap, Inc. who is the authorized warranty service agent for all Ample Power products. Their phone number is 206-789-4743, and their fax is 206-789-9003.

Email support is available from support@amplepower.com. See also the following websites for more troubleshooting suggestions.


Ample Power products are manufactured by Ample Technology, 2442 NW Market St., #43, Seattle, WA 98107 - USA


Visit http://www.amplepower.com