Review: Manzanita MK3 BMS, Part 4- The Board

The heart of the BMS is the board, and, although I’m sure various boards range from “Things of Beauty” to nightmares for people who actually know what they’re looking at, I’m not one of those people.  The important things to me are size, ease of mounting, ease of making necessary connections, stuff like that.

(All that said, my Headway BMS has a strip on the board that’s obviously built up with solder, either as a preemptive strike against a really weak circuit, or a fix of one that has already failed.  Lame, and bush-league…)

The Manzanita board is rock-solid.  It’s thin, compact, (The 8-cell MK3x8 unit is 2.37″ x 7″ x 0.938″) and has a layout that includes standard pin connections that are easily accessible.  The documentation gives you part names as well as suppliers and their part numbers for the connectors.  The main heat sink mounting bar is that L-shaped aluminum bracket you see in the photo above, foreground, and it’s set up to be easily accessible and pretty much universally adaptable to your choice of a heatsink arrangement.

The connections are pretty straightforward.  The sensor-side of the board needs connections to both sides of each cell to monitor voltage, and that’s accomplished with a Molex 10-pin connector (part number 43025-1600) and simply connects to the positive and negative terminals of each cell.  You have a temperature sensor set, shown here, that connects with a 16-pin Molex connection, and you connect a fan with a 2-pin molex plug.  You then have the Regbus I/O RJ Connections- the connectors that allow the data to be accessed by the Rodman Bus Display, the SOC head and your PC.

All the documentation, by the way, has the same detailed section on how to construct the RJ cable and connections, this being a crucial part of the assembly.

On the board itself you have 12 LED indicators (for the MK3x8):

8 Green LEDs – “Regulation Indicators”- The eight green LEDs indicate that the BMS unit is regulating. Each of the eight LEDs in the middle of the board correspond to their own independent dissipation channels. They come on when the cell they are attached to is above the regulation set point and the reg load is activated.

Yellow LED – “Undervoltage Real-time”- The yellow LED indicates that one or more of the cells in the string is/are currently below the undervoltage set point.

Red LED – “Undervoltage Latch” -The red LED indicates that one or more of the cells attached to that reg has/have gone below the undervoltage set point at some point since it was last brought to a full charge.

Blue LED– “Communication Indicator”- The blue LED indicates when the regulator is communicating on the Rudman Bus.

Here are the features:

• Real time voltage monitoring of 4 to 8 lithium cells
• Real time temperature sensing of up to 8 external temp sensors
• Additional temperature sensor included on BMS module’s heat sink
• Small size is less than 1 inch thick and 7 inches long by 2.4 inches wide
• Quick automatic cell equalization and balancing with high and low voltage on
board indicators and outputs to the charger
• Two high speed real-time warning lines which can be relay buffered for external
• All BMS modules connect together using readily available RJ cable
• BMS easily connects to a PC using the included USB adapter
• Includes free Windows based scanner and command software
• All commands are easily entered and read in simple ASCII text
• Easy user adjustable min and max voltage parameters allow flexibility for various
types of lithium cells from 1.75 to 5.5 volts per cell
• Each BMS board can bypass up to 2.5 amps per cell channel (20A total)
equating to fast charging and equalization of unbalanced cells
• Dual RJ reg bus ports for easy connection to the charger or other BMS units in a
simple daisy chain fashion
• Self regulating thermal protection and feedback to Manzanita Micro Chargers
• Built-in active variable speed 12V DC fan control output on each BMS unit. The
fan settings can be viewed and changed using the included software
• Large heat spreader is totally isolated from the cells and is already threaded for
easy mounting to a larger heat sink.
• Each unit can dissipate up to 110 watts

The full documentation can be found on the Manzanita site, in the Battery Management Downloads page.

Read more:
Review: Manzanita MK3 BMS, Part 1
Manzanita MK3 BMS, Part 2- Intro and Documentation
Manzanita MK3 BMS, Part 3- The Display
Manzanita MK3 BMS, Part 4- The Board
Manzanita MK3 BMS, Part 5- the SOC Head
Manzanita MK3 BMS, Part 6- Component Matrix
Manzanita MK3 BMS- Conclusions

Manzanita Micro site here.



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