
Specifications
Product code:
Safety relay:
Compatible with:
Dimensions:
Weight:
Operating temperature:
Maximum voltage:
Current rating:
Fuse included:
Model 24VModel 12V
79007712
12V DC 500A
MLI Ultra 12-2750 & 12-5500
total height MLI Ultra increases by 65 mm/2.5"
total weight MLI Ultra increases by 2 kg/4.4 lb
–25 to 50ºC / –13 to 122ºF
64V
300A
NO
79007724
24V DC 500A
MLI Ultra 24-5500
MLI Ultra Relay and Fuse Connect Kit
QuickStart Installation Guide
Fuse
rating
400A 300A 400A
350A 260A 350A
300A 225A 300A
250A 185A 250A
225A 170A 225A
Continuous
current
5 minutes
overload current
WARNING
If the current exceeds
300A, the busbar
conductor gets hot!
Warranty
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.
Correct Disposal
Contact your local waste disposal department
to properly dispose of the unit.
Fuse cover
ML Switch
T-Fuse holder
Busbar conductor
Bracket holes
EUROPE, MIDDLE EAST &
AFRICA
Snijdersbergweg 93
1105 AN AMSTERDAM
The Netherlands
+31 (0)20 34 22 100
info@mastervolt.com
10000017403_00
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
WARNING
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.
The T-fuse itself is not included in the kit

Required tools & material
- 13mm / ¹⁄2" socket wrench;
- 2mm / ¹⁄16" flatblade
screwdriver.
- size 3 allen key;
- Torque wrench;
- T-Fuse;
use a fuse that matches the
applied wire size.
Always dimension cables
according to the application and
local rules and regulations.
15.5 Nm max
(140 In.Lbs)
From the MLI Ultra, remove the
Battery Safety Connector (
1) and
on either side the bolt closest to
the positive terminal (2). Tilt the
positive (right) side handle (3).
3.5 Nm max
(31 In.Lbs)
MLI Ultra 5500
MLI Ultra 2750
Place the bracket over the MLI
1), aligning the bracket holes
Ultra (
with the holes of the bolts.
Tighten the bolts back in place (2).
14.7 to 19.6 Nm
(130 to 170 In.Lbs)
Secure the busbar conductor on
the bracket to the positive terminal
of the MLI Ultra.
Run the main positive battery cable
from the charger side of the system
to the B (right) side terminal of the
ML switch.
Connect the negative cable as
described in the user manual of the
MLI Ultra.
Single/paralell
connection
On the Battery Safety Connector,
move the jumper wire to pins 4 & 8.
Connect the ML Switch wires to the
Battery Safety Connector according
to the detailed figures in the user
manual of the MLI Ultra.
Put the Battery Safety Connector
back in place (
1).
On the ML Switch, set the safety
relay knob to “LOCK OFF” (2).
Check all wiring and connections.
CAUTION: Make sure all
bolts are secure (including
the bolts in the connect kit)
according to the specified
torqs.
Remove the clear fuse cover and
install the T-fuse (
1). Place the
cover back on the fuse holder.
Close the side handle as much as
possible (2). It will not close
completely.