MFJ MFJ-4275MV User Manual

MFJ-4275MVnstruction Manual
Thank you for purchasing the MFJ-4275MV Switching Power Supply.
The MFJ-4275MV is designed to deliver output current up to 75 Amps
intermittent or 70 Amps continuous at 13.8 Vdc.
Five types of output terminals are provided – 2 sets Anderson Powerpole ® , 2
sets of 5-way binding posts, 2 sets of quick connect terminals and a cigarette
lighter socket. The variable output control adjusts output from 4 Vdc to 16 Vdc.
Output control has a pre-set detent position, which sets the output at 13.8Vdc.
The battery charger provides charging current up to 20 Amps peak and 5 Amps
continuous.
The total combined output current for this power supply is 75 Amps intermittent
or 70 Amps continuous at 13.8 Vdc. Each output connection has its output
current limit as shown by the following chart. Do not draw current over the
rated limited.
Output Connections Maximum combined output current is 75
Amps, Intermittent
Gold 5-way binding posts 75 Amps
Black and Red binding Posts 40 Amps
Anderson Power Poles 35 Amps
Quick Connect Terminals 10 Amps
Cigarette Lighter Socket 10 Amps
Installation
Before plugging the MFJ-4275MV in an AC outlet make sure that the proper
input AC voltage is set to the correct AC voltage you are using. Select 115 for
100/110/120 AC operation or select 230 for 200/220/240 ac operation. 115V is
the default factory setting. Do not connect any device to the power supply yet.
Turn the power supply ON. Set the output voltage by adjusting the variable
output control in front of the power supply. The MFJ-4275MV has variable
output adjustment from 4 Vdc to 16 Vdc. The control will set the same output
voltage for all output connectors. The detent position on the output control sets
the output voltage at 13.8Vdc. Turn OFF the power supply after setting the
output voltage.
Connect the loads to the any of the output connectors. Positive to positive
terminal and negative to negative terminal. Reversed connection will damage
your equipment. For Anderson Powerpoles® connection, please refer to “the
assembly instruction” for detail assembly instructions. Connect the devices to
the power supply then turn ON the power supply.

MFJ MFJ-4275MV Specifications

General

Input Voltage	115/230 VAC
Output Voltage	13.8 VDC
Output Current (Continuous)	25 A
Output Current (Surge)	30 A
Cooling	Fan Cooled
Output Connector	Binding Posts
Metering	Analog meters for voltage and current

Summary

MFJ-4275MV Product Features and Specifications

Output Terminals and Current Limits

Lists the five types of output terminals and their respective current ratings.

Variable Output Voltage Control

Details the adjustable output voltage range from 4 Vdc to 16 Vdc with a detent at 13.8 Vdc.

Installation and Initial Setup

AC Input Voltage Selection

Instructions for setting the correct input AC voltage for operation (115V or 230V).

Setting Output Voltage

Steps to adjust and set the desired output voltage using the variable control.

Connecting Loads and Operation

Guidance on connecting devices to output connectors and initial power-on.

Protection and Battery Charging

Fault Protection Mechanisms

Explains protection against output shorts, overloads, over-voltage, and overheating.

Battery Charger Operation

Details the built-in battery charging circuit with fixed 13.8 Vdc output.

Powerpole® Connector Assembly

Connector Housing and Wire Preparation

Instructions for preparing connector housings and wires for assembly.

Terminal Crimping and Soldering

Guidance on properly crimping or soldering wires to terminals for reliable connections.

Terminal Insertion into Housing

Steps for correctly inserting the assembled terminals into the connector housing.

MFJ Limited 12-Month Warranty

Warranty Terms and Claim Procedures

Outlines requirements for retaining proof-of-purchase and submitting warranty claims.