Victron Smart BMS 12/200 connections

This is a 12 V BMS for Victron Lithium Battery Smart, including its battery-to-BMS communication chain. Lithium NG batteries use a different BMS family. The bidirectional System+ path carries 200 A continuously; the alternator input is separately limited to at most 100 A. The published 400 A system peak has no duration, so it cannot establish a starter-motor duty rating. See electrical specifications, PDF p. 13.

Battery+ connects to battery positive, System+ to the protected house system, and Alternator+ to the starter/alternator supply. GND is the BMS reference connection; the main negative return does not pass through the BMS. Tighten the M8 power connections to 10 Nm. Load-disconnect and charge-disconnect are permission signals rated to source 10 mA each; pre-alarm can source 1 A and is not short-circuit protected. None powers the controlled equipment directly.

Select the alternator fuse and configure its matching current limit in VictronConnect. The table gives 100 A charging with a 125 A fuse and 90 A with a 100 A fuse; lower options are available. These are coupled settings, not interchangeable ratings. The supplied GND lead also needs the manual’s calculated fuse, 300 mA–1.3 A depending on the connected control outputs; it is not an unfused main return. Protect battery-fed wiring and size the main system fuse for its conductor and actual load; 200 A is a BMS rating, not a universal fuse instruction. See installation and fuse table, PDF p. 10.

Remove the remote connector while wiring. Establish the negative connections, battery communication loop and permitted source/load controls before enabling the remote L/H circuit. Verify that a charge-disable request stops every charger and a load-disable request removes the intended loads. The catalog keeps alternator and system paths separate: treating all three positive studs as a busbar bypasses the limiting and protection that make this device useful.