Moving forward with BMS!

With the success of the VSR Alternator Regulator I am now moving onto companion projects.  One that I had hoped would come up in the Open Source community was a good BMS targeted for HOUSE BATTERY usage as opposed to the Electric Vehicle (EV) segment.  Sadly, despite some brave words - no action has happened.   Plus some of the popular BMS devices have been purchased and taken off the market.

So, with that I have been working on a BMS and here is a draft design:

A few key notes:

• It is designed using the STM32F072 CPU and will be programmed via the Keil IDE + CubeMX libs.   This is the standard development platform I am migrating to for better capability, and lower cost.  (However it is not as simple as the Arduino IDE to install and use...)
• Design is has some unique capability to support a best-practice LiFeP04 house battery.  Notable features include:
• Support for LiFeP04 main battery + small 'keeper' battery, typical an AGM starter battery.
• Independent Voltage and Temperature sensing circuits for main and keeper battery
• Support for battery disconnect of LiFeP04 (keeper battery remains connected)
• Support for optional cell-level devices for Voltage, Temperature and balancing.

And of course this can be used with other traditional battery technologies, FLA, AGM, etc.   Just like the Alternator Regulator.

The concept of a 'keeper' battery when deploying LiFeP04 house battery banks allows for better systems management, especially during long periods of rest.   And with this will be the introduction of Battery Scenarios, where how a battery is treated is different on its current usage.  A prime example again is the LiFeP04 technology which desired to be at a modest SOC during extended periods of disuses (Think Winter Moorage).  This is a KEY difference in house oriented BMS vs. one designed for EVs.


Much more to come on this, including the cell level boards.  But I am hopping to have working systems by the end of this summer.

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I was also challenged to make a KISS BatMon (Battery Monitor), and here is an idea:

About as simple as I can make it - 3x ICs, a PS chip and a LED.  In addition to is function as an RBM it can also act as a 'port extended' for the regulator.  Based on the Arduino IDE, but I have stripped the built-in USB port, one would need to purchase a USB to Serial dongle (under $2 on Ebay).  BOM + PCB comes in around $10 for this device, but then there is the problem of getting it assembled at a reasonable cost.  When looking at it one wonders if there is a need for both  the BMS and this BatMon..   So for now it just an exercise, but who knows what may happen in the future..