Hybrid Operation. Emerson M820B, M820D

User Instructions

Spec No. 1M820BNA (Model M820B)

UM1M820BNA

Issue AH, March 4, 2013

Spec No. 1M820DNA (Model M820D)

Fixed Daily Time based operation is intended to be used with a combination of AC powered active cooling (air conditioners) and DC powered cooling (heat exchangers, etc). The cycle period is synchronized to the 24hr day-night cycle. It makes optimum use of the different temperature conditions during the day and the night in order to facilitate Hybrid fuel saving operation.

Capacity Discharge based operation is intended for sites utilizing only DC powered cooling (heat exchangers, etc). The cycle period is determined by User selectable depth of discharge (DOD) of the batteries per cycle and associated recharge time. It provides optimum Hybrid fuel saving operation.

Operation from Grid Power is performed with both Fixed Daily Time and Capacity Discharge modes of operation. Grid power is always given priority when available.

As the two types of control are specific to the hardware configuration of the site, the Fixed Daily Time or

Capacity Discharge is a User selectable option on installation.

Hybrid Operation

Generator Control: Potential free relay contact output from the ACU+ interface board controls the start and stop of the diesel generator. The signal is generated by the ACU+ Controller and operates according to the Hybrid software mode of operation. The control logic is as follows:

Energized output relay

– Generator OFF.

De-energized output relay

– Generator ON.

This is a fail-safe logic to ensure generator operation in all cases where power or control to the relay is lost.

Further to that, the type of signal to the generator can be selected as N/O (Normally Open) or N/C

(Normally Closed) by selecting the relevant output pins of the control relay.

Number of Generator Control Outputs: The ACU+ Hybrid software can control one or two generators.

Each generator control is designated as DG1 or DG2 output. A User selectable menu will allow selecting

DG1, DG2, or DG1 and DG2. When both are selected they will be alternatively used (two generator operation).

Diesel Fail Alarm: A diesel fail alarm will be generated if the Diesel Generator ON signal fails to bring the generator to operation and provide the system with AC power. Alarm will be triggered after 60 seconds

(default value, settable) from ON signal. If two generator operations are selected simultaneously with the alarm, the second Diesel Generator ON signal will be activated.

Battery Fuse Trip Alarm: In the event of a Battery Fuse trip condition an alarm will be generated.

Under Voltage Alarms:

Under Voltage Alarm 1: An Under Voltage Alarm 1 is set. If voltage decreases below this setting, an alarm is raised.

Under Voltage Alarm 2: An Under Voltage Alarm 2 is set. If voltage decreases below this setting, the

Diesel Generator is started and an alarm is raised.

LVD 1: Normal loads are disconnected.

LVD 2: Priority loads are disconnected.

Charge Voltage:

Refer to Figure 6.

Chapter 1. Introduction 11

This document is property of Emerson Network Power, Energy Systems, North America, Inc. and contains confidential and proprietary information owned by Emerson Network Power, Energy

Systems, North America, Inc. Any copying, use, or disclosure of it without the written permission of Emerson Network Power, Energy Systems, North America, Inc. is strictly prohibited.

UM1M820BNA

Issue AH, March 4, 2013

User Instructions

Spec No. 1M820BNA (Model M820B)

Spec No. 1M820DNA (Model M820D)

Figure 6

Charge Voltage

Equalize Charge: The battery will be recharged at equalize voltage. This is the voltage set in the initial

phase of battery recharge. See Figure 6.

As the voltage limit is reached, the charge current is gradually reduced

– effect known as current tail.

When the current tail falls below a set of threshold levels, additional equalize charge time is added.

The equalize charge current tail threshold is settable from 0.01 to 0.05. Default setting is 0.02 (2A per

100Ah). The additional equalize charge time is settable from 0 hours to 7 hours (settable in minutes from

0 to 720), default setting is 4 hours. The duration of the equalize charge is determined as the time from the start of the recharge to the end of the additional time. (Maximum charge time, determined from the time charge starts, is settable in the range of 5-24h.)

The end of recharge is determined by a three (3) step approach:

Step1 - calculated battery capacity exceeds 90%. Calculation is performed by measurement of battery current and time, in Ah.

Step 2 - charge current tail threshold is reached.

Step 3 - additional charge time is added.

Float Charge: Default float voltage is 54.0V at 20°C with a temperature compensation of -72mV per °C.

If battery temperature exceeds 38°C, the charge voltage is reduced to 51V to reduce gassing and prevent thermal runaway. The same is applicable as well for equalizing charge.

Equalizing Charge: As the cyclic use does not ensure complete battery recharge after every cycle, an equalizing charge cycle is added. The equalizing cycle will occur up to four times a month, settable for every 7 to 60 days intervals. Start date and time is settable. Equalizing charge time is 20 hours independent of discharge time setting. Equalizing charge is performed at equalize voltage until end of

additional equalize time and thereafter at float voltage for the remaining time. Also see Figure 6.

Equalize charge independently settable 0-720 min (already set in equalize charge).

12 Chapter 1. Introduction

This document is property of Emerson Network Power, Energy Systems, North America, Inc. and contains confidential and proprietary information owned by Emerson Network Power, Energy

Systems, North America, Inc. Any copying, use, or disclosure of it without the written permission of Emerson Network Power, Energy Systems, North America, Inc. is strictly prohibited.