Installation and Operating Instructions

EM-RELAY-12V and EM-RELAY-24V October 31, 2001
Copyright ©1994 through 2001. All Rights Reserved - Ample Technology


The EM-Relay is used in conjunction with the Energy Monitor to control solar panels or wind generators. The Energy Monitor opens and closes the relay in accordance with the user programmable setpoints.

NOTE: A separate EM-Relay is required for solar and wind generators.

Models are available for 12 or 24 Volt systems.

EM-Relays can also be used to buffer the alarm and start/stop signals, providing a contact closure for an alarm, or run condition.

Input Control

Control is achieved using an optical coupler. The coupler isolates current from the Energy Monitor and high currents being switched on and off by the relay, eliminating noise transients. The input is buffered with a MOSFET to permit control with minimal current demand from the Energy Monitor.

Output Contact Rating

The EM-Relay contacts are rated for 40 Amps with solar panels and 30 Amps with wind generators.

Signal Names and Functions

NOTE: There are two terminal blocks on the EM-RElay, TB1, and TB2. TB1 refers to the 4-pin terminal block and TB2 refers to the 3-pin terminal block.

Orient the terminal blocks so that Pin 1 is at the left.

NOTE: The negative outputs from the solar panel or wind generator must be wired to ground, although they may be connected through a shunt to ground.

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 TB1-2 and TB1-4 first. Use separate wires as shown on the diagram ...combining any of these wires may reduce stability.

$\bullet$ Twisted, Shielded Pair :: Always use a twisted, shielded pair for the shunt sense wires. Terminate the shield lead at the shunt.

$\bullet$ 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 Diagrams





Troubleshooting Information

$\bullet$ Signal to close :: A positive voltage is required on TB1-1 for the relay to be actuated and a negative voltage at TB1-2.

$\bullet$ Voltage to close relay:: A positive voltage is required on TB1-3 for the relay to be actuated. Note that TB1-4 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