Congratulations on your new purchase, this article in intended to help you get started with the installation and commissioning of your new system.  The original article is from August 2020 and it will be updated frequently until it is complete, so please check back again later to see if more information has been added.


Lithium batteries contain a lot of energy.  They are shipped with approximately a 50% charge.  As soon as you open the box please tape over the terminals and don't untape them until you are ready for programing and commissioning.  If you drop a wrench on the terminals during installation you will be very sorry.  In the completed installation the battery terminals need to have rubber boots for the same reason.

Batteries need to be tied down securely.  If you are installing these in a boat imagine what would happen if it rolled over.  If you are installing these in a vehicle imagine what would happen in an accident.

In a motor vehicle the start battery and the auxiliary battery must both be grounded to the chassis.  If you have an inverter or shore power the AC ground must also be bonded to the chassis.   In a boat the AC ground gets connected to the engine block.


Make sure you read all the instructions before you start.  This article is just an introduction.  Here are the links to the main instruction manuals.  Every system is different so if something in your system is not included please read its manual too.  Note that the instruction manuals are updated constantly, if you find a broken link here please let me know.

Victron have an index of instruction manuals, datasheets, system schematics, and technical information on their site.  There are also instruction manuals available for some of the minor components, like the inverting remote on off cable and the non inverting remote on off cable.  The wiring diagrams I have given you are outlines only and for clarity they don't show all the small connections.  They are intended to be read in conjunction with the wiring diagrams in the instruction manuals.


At the very end I am going to ask you to make a record of your system and save a list of the items you installed, together with serial numbers and any program files, screenshots and all the other information on a computer somewhere so you can refer to it in the future.  A year from now there may be a question and you are not going to remember any of it.  Ideally put it in a dropbox or some other shareable file.  Take photos of the serial numbers of all your equipment.  They are required if there is a warranty issue.  If you take a photo now you wont have to unscrew the item or take it apart to get its serial number.  Here is a link to my article about testing which includes notes about keeping records.  


You can check on the status of your batteries before you even open the box.  Just open the Victron Connect app and connect to them one at a time.  Often you will need to update the firmware in the battery before you even start, this is all done with the aid of prompts in the app and only takes a minute or two.  The Victron Connect app gets updated frequently so you should keep your app up to date and then it will automatically keep your equipment up to date every time you connect to it.  The batteries are identified by their serial number.  You should save a screenshot of each battery as it arrived.  It will look a bit like this:

Battery Screenshot

The cells will be somewhere between their low voltage shut off of 2.8 volts and their high voltage shutoff of 4 volts.  You may see a slight variation of voltage between the cells as is shown here.      

The program will prompt you to add a Bluetooth password to the batteries, and for every other device you connect to.  For those of you in the RV world we recommend you do this because on busy campsites you will find a lot of Victron gear to connect to and it would be possible for someone to accidentally or maliciously change your settings or even turn off the Bluetooth in the batteries.  If you turn off the Bluetooth in the batteries there is not way to turn it back on again.  There is also a way to name your devices which makes it easy to find your own ones if a lot show up on the screen.

If you have multiple batteries in your system you might need to charge them individually to get them to the same state of charge.  For batteries in parallel this is only necessary if there is a substantial difference of voltage between them, but for batteries that are in series they need to be charged to full which is 14.2 volts.  This first charge needs to be done slowly and with a charger that you know will stop at 14.2 volts.  Since there will be no BMS connected for this first charge you need to be the human BMS and keep an eye on the cells.  When the battery is at 14.2 volts each cell will be approximately at 3.55 volts.  Anyone buying a system from PKYS with batteries in series will have had the opportunity to buy a small low power charger that is suitable for this first charge.

Attention should be paid to mounting the batteries in a secure way.  Batteries need to be adequately restrained, for motor vehicles that means protecting them in the event of an accident, for boats it means restraining them in the event of a capsize.  If you have multiple batteries in the system you also need to allow a minimum 20 mm air gap between each one. (see manual for details)


We already mentioned that the batteries contain a lot of energy.  The circuit protection is required to be sure that the energy doesn't get released in an inappropriate way.  Each system will have a primary fuse which will be a Class T type.  This is designed to blow in the event of a catastrophic short circuit.  In addition if you have multiple batteries or strings of batteries in parallel each battery or string of batteries gets its own fuse.  This is to protect from a battery fault that might cause one battery to dump into another battery.   The Class T fuse is to go as close to the battery as practical because it only protects which comes after,

Since the Class T main fuse is the largest in the system each device that you connect then gets its own fuse that is appropriate to the size of wire you are using to connect it.  The Ampacity Table shows what size fuse goes with what size wire.  Dont forget that any exposed positive connections need to be covered to avoid accidental short circuit.

Here, taken from the ampacity table, is a summary of what wire size goes with what fuse.  This is the minimum wire size, there is nothing to stop you having a bigger wire and it DC systems it will give you reduced voltage drop.

  • 400 Amp fuse – 4/0 awg cable
  • 350 Amp fuse – 2/0 awg cable
  • 300 Amp fuse -1/0 awg cable
  • 250 Amp fuse - 1 awg cable 
  • 200 Amp fuse – 2 awg cable
  • 150 Amp fuse – 4 awg cable
  • 120 Amp fuse – 6 awg cable
  • 100 Amp fuse – 8 awg cable


We are building an externally managed battery system.  The BMS is in charge of deciding if a charge source is allowed to charge the battery or if a load is allowed to discharge the battery.  Your job is to connect up the system in a way that this happens automatically.  You have to test it to make sure it works as it is supposed to as you go through the installation and again when you are finished   Don't connect anything in to the system until you are sure that you understand how this is going to be accomplished.  I am going to go through the typical parts of a system and talk about each device one at a time.  If there is some other device in your system that isn't mentioned here then you have to satisfy yourself that you have figured out how it is controlled and programmed and then test it out when you are done.

There are two black data cables that go to each battery.  In a one battery system the two ends connect directly to the BMS.  In a multiple battery installation they daisy chain from one battery to the next and the two outer ends connect to the BMS.  When the data cables are connected and all the cells in the battery are between 2.8 volts and 4 volts the BMS will be on.  If you disconnect one of the data cables the BMS will turn off and should turn off all the devices in the system.  This is the simple way that you can test each device that you connect to the battery.  

I wrote my own installation and operation manual for the Smart BMS CL 12-100 

This part of the article explains how devices are managed.  In another section further down I will discuss other programming settings.  In reality both parts of the programming would be done at the same time but I have separated them for clarity.


If you have a VE Bus BMS in your system the MultiPlus connects to the BMS using a VE Bus cable. There is a device called a mains detector that is supplied with the BMS and it goes in the line between the BMS and the MultiPlus.  Details are in the instruction manual for the VE Bus BMS.   Then the MultiPlus gets programmed with the VE Bus Assistant.  You have to use the VE configure program to do this and it requires a PC and a Mk3 USB interface.  The process for doing this is in described in part three of my article about programming the MultiPlus.  You might want to reads parts one and two first.  When you are done test it out as previously described.

MULTIPLUS with Smart BMS CL 12/100

If you have a MultiPlus (other than a MultiPlus Compact)  it gets connected with a pair of Inverting Remote On-Off Cables.  The Multi gets programmed with the "Two Wire BMS Support Assistant"     You get to decide in the programming menu where you are going to connect the remote on off cables.
There is a simpler connection for the MultiPlus Compact that doesn't involve any programming, it is described in the Smart BMS CL 12/100 manual
When you are done test it out.


DC loads are turned off using the Smart BatteryProtect.  You have to program the BatteryProtect to program "C" Lithium Battery.  You have to remove the little black jumper in the green remote plug that otherwise would keep it on all the time.   The Load Disconnect output of the BMS goes to terminal H of the BatteryProtect.  The BatteryProtect is a one way device so for this particular application the battery gets connected to the IN terminal and the load gets connected to the OUT terminal. You must connect the negative terminal of the BatteryProtect for it to work.  See further down for more detailed programming information. When you are done test it out.


If you have a Venus GX device in the system the MPPT charge controllers VE Direct port is not available and so you have to use a BatteryProtect between the MPPT and the battery.  In this case the IN of the BatteryProtect is the MPPT the the OUT is the battery.  Remember this is a one way device and in this case it is for charging the battery.  It needs to get programmed for program "C" Lithium Battery as described above but in this case it is the Charge Disconnect terminal of the BMS that gets connect to terminal H. When you are done test it out.


If there is no Venus GX device in the system then the VE Direct port is available for direct control using the non-inverting remote on-off cable.  It goes from the VE Direct port of the MPPT to the charge disconnect terminal of the BMS.  When you are done test it out.


This is an automatic combiner that goes between the start battery and the lithium battery.  Don't mix up which terminal goes to which battery, they are labelled.  The red control wire goes to the BMS Charge Disconnect, the black goes to battery negative.  Test it out.


We haven't had the opportunity to try these out yet but there is a remote terminal.  You need to remove the jumper of the remote terminal otherwise it would be on all the time.  Then the Charge Disconnect terminal from the BMS goes to the H terminal.  Double test this out since we haven't had the opportunity to try it out ourselves.


The functions of the green and purple wires can be set up in the program.  Set up one to be an On-Off signal and connect it to the Charge Disconnect of the BMS


Usually with other devices we use a Battery Protect in some way.  Remember the battery protect is a one way device so be aware of what it is doing.   For example if you have a a battery charger you can put a BatteryProtect between it and the battery and connect the remote terminal to the Charge Disconnect of the BMS
If you have an alternator charging the lithium battery direct you can use a BatteryProtect on the power supply to the regulator to turn off the regulator when the battery is full.  The in of the BatteryProtect would be the battery, the out would be the regulator,  The remote terminal would go to the BMS charge disconnect.


The simple test of disconnecting the data cable of the battery justs tests that the device is being controlled by the BMS.  It doesn't test if you are doing the right action for the circumstance.  Don't mix up the functions of charge disconnect and load disconnect.  At the very end I suggest you do a real system test and let the battery run all the way down.  This is covered more fully in my article on testing out your system


The list above just covers programming the devices to turn off when they are supposed to.  There are other aspects of programming too and these would all be done at the same time, I just split the two sections apart to illustrate the point that the most important programming action is to make sure the devices are controlled by the BMS.  Everything else can be tweaked later but if you let your battery run flat then it might be ruined so we don't want that to happen.  I will go through the list again for each item:


Programming the MultiPlus is described in detail in my set of articles.starting here with Programming your MultiPlus Part 1   When it comes to battery charging there is a pre-programmed setting for Lithium Batteries so that is all you have to do there.  In those articles I made some suggestions about setting the low voltage shutdown to happen before the battery shuts down.  

Here are some suggested settings for the inverter page designed to make it shut down before the battery gets totally down.  I have unchecked the Power Assist and using it might require you to fit bigger wires on the output side.

Clicking the Lithium Preset on the charger page automatically gives you these settings:

And on the Assistants page you have to select either the VE Bus BMS Assistant or the Two Wire BMS Assistant depending on which BMS you are using


The Battery Protects need to be programmed for setting C, Lithium mode as shown below.

Don't forget to remove the jumper


Here are the recommended settings:

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