It won’t work without the chip in the top left.
Is CANBUS only compatible with Victron? I have a SMA Sunny Island and would like to build another DIYBMS pack for this inverter but really need CANBUS integration to control charging.
Here is the data that Sunny Island is expecting from diyBMS. If I compare this to victron_canbus.cpp code, it seems to hit all of the required data, so I’m optimistic it would work.
The code has not been tested against the sma devices, but if you can try it, that would be excellent.
I only have the earlier version of the board without Canbus pins. I’ll start a new build. I’ll check back in with you in about a month or two and let you know how it goes. haha! 
i will test this with my sma sunny island, if i can manage to program the shunt pcb…
Hi, thank you for the detailed explanation. Can you send me the compiled firmware with the modification you mentioned?
Apparently it’s available in TSSOP and SOIC versions. You need TSSOP.
Greetings Everyone, looks like I am late to the party.
I initially discovered this project a year ago, in a “Great Scott” YouTube video. As I get closer to building my 18650 packs my choice of a BMS has to be addressed. So I have started following these great BMS efforts much closer.
I am planning on using this system for my 840 cell 14s10p set of 6 packs.
My current questions involve the github repository concerning the best branch and tag to use this day, May 2, 2022.
The “diyBMSv4” repository where the “MODULEV440” and “ControllerCircuit” reside, there are 2 branches, “master” and “Experimental_2022Feb”. There are also multiple Tags. What is the preferred branch and tag to order from JLCPCB?
The “diyBMS-CurrentShunt” repository where the CurrentShuntCircuit reside, there are 2 branches, “master” and “optoisolator-changes”. There are also multiple Tags. What is the preferred branch and tag to order from JLCPCB?
Thank you for reading this far.
Master is the currently supported version.
There are changes occuring all the time in some of the other branches, but they will get merged into master when they are ready.
V4.40 of the modules is the latest.
I have placed an order with JLCPCB. The Shunt order for 5 boards and assembly did not seem right. After my upload of gerber, bom and cpl, JCLPCB only lists the 3 components. Because I chose the top side not the bottom. Choosing the bottom side corrected the issue.
I apologize if this is the wrong place for this question. Disclaimer: I am a software engineer and e-bike enthusiast. I know just enough about hardware to make costly mistakes. I’m learning, though.
Here’s my situation: I have an e-bike of sorts (an Organic Transit ELF) that I have upgraded with a second motor. So, the original battery pack (with a 40A BMS) is insufficient. So, I built a Li-Ion 14sx4p battery pack consisting of 21700 cells that claim to be capable of 45A continuous discharge (Molicell INR-21700-P42A). So, at 4P, that’s a theoretical output of 180A.
I only need about 80A, and I can (and do) control this with the motor controllers and a regulating computer (Cycle Analyst). There is also a 120A fuse on the battery pack itself, as a failsafe (well short of the 180A that the pack can theoretically handle).
So, maybe this is all I really need to do to protect myself from an over-current discharge problem? I am just accustomed to having the BMS also protect against exceeding a set discharge current limit.
The Cycle Analyst (CA) is clever about this, though. The throttle input goes to the CA, which has a configurable max discharge current, and the CA sends translated throttle signals to the two motor controllers. So, as the load approaches the max discharge current, the CA dials back the throttle signal to the controllers to prevent exceeding the current limit.
And, with the 120A fuse, maybe this is OK, and I don’t need the BMS to be involved in limiting discharge current. Thoughts?
So, for my purposes, I would just need 14 monitoring modules and a controller. Yes?
Then, as I’m understanding things so far, I have some decisions to make with regards to resistors and MOSFETs? I’m just about a day or so into reading up on diyBMS, so am a little fuzzy on the details. Just looking for a basic sanity check to see that I am on the right track.
Cheers,
-B
Thank you for your quick reply. I need to adjust my battery design to your distributed BMS before I build my battery.
My battery design is for 48 Volts. I need to know if just ONE DiyBMS Monitor v4 can control 14 - 18650 Batteries connected in Series ? Peak voltage would be 58.8 Volts at 2.6 Amps. It looks like all examples I’ve seen show only 4.1 - 4.2 Volts for each Monitor. Any additional comments would be welcome.
Thanks again
What’s a “monitor”? diyBMS has modules (you need one per cell) and controllers (you need one per heap-of-batteries).
Hello,
thank you for your quick response. I am referring to the diyBMSv4/ModuleV440/.
I need to know if just ONE diyBMSv4/ModuleV440/ can control
14 - 18650 Batteries connected in Series ?
Another question
Can 2 or more diyBMSv4/ControllerCircuit/ be connected to manage 1 large battery? This would reduce the number of diyBMSv4/ModuleV440/ managed by a single ControllerCircuit ?
Please ask any additional questions to help me grasp the BMS system requirements.
Thanks again
Easy:
No.
Howard. You don´t understand the function of the BMS system of Steward.
The controller board gets datas from the cell boards.
The controller tells the cell boards when they have to discharge current.
The cell board measures the voltage of the battery cell.
( It does not measure the whole battery. )
The battery voltage has to be that from a liion cell.
This is depending on the cell up to a max of 4.2V.
You cant control a line of 14 cells with one board.
You could control a parallel pack of 14 cells with a unique voltage up to 4.2
For a line of 14 cells you need 14 V4.40 cell boards.
You only need one monitor board. V4 of the small one or 4.2 of the 32 board.
The monitor can handle datas of up to 100 cell boards.
The cell boards are connected in a row.
At the beginning and the end of the row is the monitor. Its a circle.
Please checkout Stewards youtube videos…
Thank you for your response.
If you would look at the youtube video of :
“DIYBMS V4 Introduction” at “DIYBMS V4 Introduction - YouTube” at the time of 6:25.
The individual settings of the module are briefly discussed here. I don’t understand what the maximum voltage that could be entered. I do understand what you are saying and I agree.
Although, I thought I should mention my thought, even if it was not well founded.
BTW, Who is Steward ? Are you referring to Mr. Stuart Pittaway, the developer of the diyBMS ?