Answer
Sep 04, 2025 - 07:46 AM
2/0 cables are actually not that large for the MultiPlus 12/3000. The recommended fuse size is 400 amps and since the fuse is to protect the wire it means that you must use 4/0 wire to meet that requirement. Its also possible that you have loose connections along the way. Your wiring presumably goes through a battery switch and fuse so including the battery and inverter terminals as well as the fuse and switch terminals you have a minimum of 8 connections in the circuit. You should examine each connection in turn, make sure you have the correct sequence of nut, lock washer, washer and stud to make a proper connection and have torqued the nuts to the approved settings. The MultiPlus instruction manual includes torque settings for its bolts. You can check the efficiency of your connections when under load by measuring their temperature with an infra red laser thermometer, a hot reading under load indicates a bad connection.
Your MultiPlus also has a dedicated terminal to use for voltage measurement. Use of this cable is optional but it does provide a way of measuring voltage directly at the battery terminals along a wire that carries no current. Here is a link to that part in the MultiPlus-II manual, there is an equivalent one in the original MultiPlus. If you dont install the reference wire then you need to compare what the multiplus reports with a reading as measured at the multiplus battery terminals so you are comparing like with like.
The default temp compensation for a 12 volt battery is -16.20mV/°C, since there are 6 cells in a 12 volt battery that is -2.7mV/°C per cell. Trojans recommendations are very conservative and back off charging at higher temperatures more than other manufacturers. I was able to see the compensation to -30.00mV/°C by scrolling through all the values. It wont let you type in the number directly. It stopped scrolling at 29.99mV/°C but once I clicked OK it changed to -30.00mV/°C
Your MultiPlus also has a dedicated terminal to use for voltage measurement. Use of this cable is optional but it does provide a way of measuring voltage directly at the battery terminals along a wire that carries no current. Here is a link to that part in the MultiPlus-II manual, there is an equivalent one in the original MultiPlus. If you dont install the reference wire then you need to compare what the multiplus reports with a reading as measured at the multiplus battery terminals so you are comparing like with like.
The default temp compensation for a 12 volt battery is -16.20mV/°C, since there are 6 cells in a 12 volt battery that is -2.7mV/°C per cell. Trojans recommendations are very conservative and back off charging at higher temperatures more than other manufacturers. I was able to see the compensation to -30.00mV/°C by scrolling through all the values. It wont let you type in the number directly. It stopped scrolling at 29.99mV/°C but once I clicked OK it changed to -30.00mV/°C
