C.E. Niehoff & Co. A2-149, A2-155 Regulator Installation

A2-149 & A2-155

Regulators

Installation Instructions

Table 1 – Voltage Select Switch Position

4 Voltage Setpoints (Fig. 1)

Position 1 14.0 V

Position 2 14.4 V

Position 3 14.8 V

Position 4 15.5 V

Note: On Group 31 batteries, if boiling or excessive gassing occurs with high voltage
setpoint (position 3), change to medium voltage setpoint (position 2).

1. Before installing, turn regulator over and select
appropriate voltage setpoint for battery type
(See Table 1 and Fig. 1).

2. Install new regulator as described below:

a. Mount new regulator on alternator in the

same position as the previous regulator.

b. Use screws and washers (if supplied).

Torque regulator mounting screws to

8.5 Nm/75 lb. in.

3. Plug the alternator-to-regulator harness into the
regulator.

4. A2-155 regulator connections:

Maintenance (D Category)

Maintenance-Free (Group 31)

Maintenance-Free (Group 31)

Battery Type

Battery Isolator setpoint

5. A2-149 regulator connections:

• D+ terminal provides 14 VDC voltage output
to multiplex controller. When connecting D+
terminal to controller through a relay, the
relay coil must be diode protected and rated
for proper voltage. Torque M5 terminal
nut on regulator to 4.5 Nm/40 lb. in.

• Connect R terminal to tachometer or relay.
R terminal taps AC voltage, typically half the
charge voltage. Torque M6 terminal nut
on regulator to 4.5 Nm/40 lb. in.

2

3

1

Figure 1 – 4 Voltage Setpoints

4

• Connect IGN terminal to ignition source
through existing switch. Torque M5 terminal
nut on regulator to 4.5 Nm/40 lb. in.

• Connect P terminal to tachometer or relay.
P terminal taps AC voltage, typically half
the charge voltage. Torque M6 terminal nut
on regulator to 4.5 Nm/40 lb. in.

C. E. Niehoff & Co. • 2021 Lee Street • Evanston, IL 60202 Tech Services Hotline [phone]

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