Which Starter Kit Do I Get
The configurations of our products are very specific for each customer. Everyone wants something different, therefore, they choose the product which best suits their needs. We do not choose for you, we can only give you advice on what is available, but it your choice in the end.
Please remember that at least a rudimentary knowledge of electronic circuits and batteries are needed to build a battery pack and attach a BMS. I cannot tell you how many times perfectly good equipment has been damaged because of lack of knowledge.
The first thing needed is a Starter kit, then you will have the basics to begin your home pack. Below is a guide which will help you choose which starter kit suits you.
To decide which starter kit you require, you need to ask yourself a few questions:
1. Which cell monitor is best for me? - This depends on the battery you have chosen. All our cell monitors have equivalent specifications regarding measurements so the choice is really about ease of attachment. This article should help with the choice https://support.batrium.com/article/75-what-type-of-cell-monitor-should-i-choose Please note that if your battery has a shared loom then it is should not be used with WatchMon4.
WatchMonPlus was designed to be used with shared looms such as those used on Tesla batteries. WM5 is our 48V WatchMonPlus and WM7 is our 24V WatchMonPlus.
If using LTO batteries then WM5 is 24V and WM7 is 12V.
2. How many cell monitors do I need?
Each distributed cell monitor measures between 2.2 V and 5 V. People with LTO batteries should use WatchMonPlus. For 14 cells in series (14s system) you would need 14 cell monitors. If you are doing other configurations, you would need one (1) cell monitor for each cell in series. You do not require extra cell monitors for the cells in parallel, as they are measured as a unit. WM5 allows between 10s and 15s configurations and WM7 allows between 6s and 10s configurations.
Eg: 14s100p would require 14 cell monitors .
Eg: Two banks of 14s50p would require 28 cell monitors. (See multi string information below).
3. Do I need State of Charge?
Recommended but not essential unless planning to attach to an inverter via CAN. The SOC% sensor is like a fuel gauge.
4. Do I need the expansion board version or is WatchMon 4 Solo sufficient?
The purpose of the Expansion board is to connect to external devices such as a fan, heater, contactor or circuit breaker etc. The expansion board also contains both relays and mosfet digital outputs. Due to popular demand, WatchMon 4 was created with has two mosfet outputs and WatchMonPlus (WM5 and WM7) have these too, therefore the expansion board is only needed if customers specifically want to use relays or if more than two (2) outputs are required. You need to look at your own circumstance and to what you wish to connect, to decide if this is needed for you.
5. Are you connecting an inverter/charger via CANbus?
All our WatchMon are capable of CANbus messaging. Only some inverters or chargers can be hooked up via CANbus and share information. The interface is specific to the inverter and the amount of information able to be shared varies greatly depending on the complexity of the inverter. In all cases a SOC% sensor is required if connecting the inverter this way, the EnPower charger does not require SOC% for the interface.
If your inverter is capable of CANbus but not one that we have tested, please refer to What if my inverter isn't on your compatible list.