Mastervolt MLI Ultra Series

The Mastervolt product warranty covers this product for the first two years after the
purchase date. The warranty is limited to the cost of repair and/or replacement of the
product. Costs of labor or shipping are not covered by this warranty.
Mastervolt cannot accept liability for damage due to the misuse of the product.
Warranty
EUROPE, MIDDLE EAST &
AFRICA
Snijdersbergweg 93
1105 AN AMSTERDAM
The Netherlands
+31 (0)20 34 22 100
info@mastervolt.com
ASIA/PACIFIC
42 Apollo Drive, Rosedale
AUCKLAND 0632
New Zealand
+ 64 9 415 7261
enquiries@bepmarine.com
AMERICAS & CARIBBEAN
N86 W12500 Westbrook Crossing
Menomonee Falls, WISCONSIN
53051
USA
+1 800 307 6702
tsusa@mastervolt.com
Contact your local waste disposal department
to properly dispose of the unit.
Correct Disposal
MLI Ultra Relay and Fuse Connect Kit
QuickStart Installation Guide
10000017403_00
Specifications
Product code:
Safety relay:
Compatible with:
Current rating:
Nominal voltage:
Dimensions:
Weight:
Operating temperature:
79007712
12V DC 500A
MLI Ultra 12-2750 & 12-5500
300A
48V
total height increases by 65 mm/2.5"
total weight increases by 2 kg/4.4 lb
–25 to 50ºC / –13 to 122ºF
79007724
24V DC 500A
MLI Ultra 24-5500
Carefully read the safety instructions that come with the used
products, before starting!
If you are not knowledgeable about electrical systems, have an
electrical professional install this kit.
WARNING
The T-fuse itself is not included in the kit
Model 24VModel 12V
If the current exceeds
300A, the busbar
conductor gets hot!
WARNING
Fuse
rating
Continuous
current
5 minutes
overload current
400A 300A 400A
350A 260A 350A
300A 225A 300A
250A 185A 250A
225A 170A 225A
Bracket holes
ML Switch
T-Fuse holder
Busbar conductor
Fuse cover

Mastervolt MLI Ultra Series Specifications

General

Series	MLI Ultra Series
Category	Relays
Protection	Overload, short circuit, over temperature
Weight	Varies by model
Current Rating	500 A
Operating Temperature	-20°C to +60°C
Humidity Range	5% to 95% non-condensing
Communication	MasterBus
Voltage Range	12 V, 24 V

Summary

Product Specifications

High Current Operation Warning

Warning that busbar conductor gets hot if current exceeds 300A.

Warranty Information

Correct Disposal Procedure

General Safety Instructions

Required Tools and Materials

Installation Steps

Step 1: Remove Battery Safety Connector

Remove the Battery Safety Connector and specific bolts from the MLI Ultra, then tilt the positive side handle.

Step 2: Secure Busbar Conductor

Place the bracket over the MLI Ultra, align holes, and tighten bolts to secure the busbar conductor to the positive terminal.

Step 3: Connect Main Cables

Run the main positive battery cable to the ML switch and connect the negative cable per the MLI Ultra manual.

Step 4: Configure Battery Safety Connector

Move the jumper wire on the Battery Safety Connector to pins 4 & 8 and connect ML Switch wires.

Step 5: Final Assembly and Checks

Reinstall the Battery Safety Connector, set ML Switch to 'LOCK OFF', and check all wiring and connections.

Step 6: Install Fuse

Remove fuse cover, install T-fuse, replace cover, and close side handle as much as possible.