FlexiBMS - 0.2 HW under work - Flexible configuration and charging BMS

Fully assembled!

I suppose it’s time to start testing and coding.

Boost converter noise performance is going to be under particular supervision, because the 0.1 had terrible ringing at it’s output, but the electrolytic capacitors have been optimized and a nice bunch of ceramic caps have been added to address the issue, but testing will confirm how it works.

PS. I’ll try to sort out the BOM finally and update it to the repo.

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Are you planning on making a production run of these? I imagine many would sign up to buy this beauty! :heart_eyes:

Once I have tested it and if it has passed with no major or critical flaws I might do a hand assembled small batch that I will ship out (maybe free or not) to couple willing beta testers who preferably are esk8 power users and familiar with electronics, so they can test it and give feedback.

I refer back to a post on this particular issue couple months back

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Nice piece of art Simos !!! And now good luck for the coding part ! I might be interested into particpating to the beta program :wink:

Now let’s hope it doesn’t stay just as an art piece.

the expression or application of human creative skill and imagination, typically in a visual form such as painting or sculpture, producing works to be appreciated primarily for their beauty or emotional power.

:smile: Now you’re done with the “beauty” part. Let’s dive into the “emotional power” one. :wink:

Repo has been updated with 0.2 HW finalized files with BOM now up-to-date and available in .csv and .pdf formats.

PROJECT LICENSE UPDATED Project license changed from GNU GENERAL PUBLIC LICENSE to Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International. This is because the project is more of a hardware one than a software one. If you have questions what this means in practice, or at least what I want it to achieve in practive, ask away.

I’ve also been doing some concept work on an open source remote with flexibility in it’s configuration called FlexiRemote (Imaginative, I know right?). It would be based on an arduino nano and Nordic semiconductors nRF24L01 modules and the idea would be to allow the user to 3D-print the case for either thumbwheel with dead man switch or trigger control with switch. I’m also going to put a place for a 0.91" 128x32 OLED display. Charging will be done via the arduino nano’s USB-mini connection.

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Why not go for a nodeMCU (or ESP8266 for that matter) - seems to be more performant and cheaper in the end.

Just to be clear to everyone, this license means you can use this design for free ONLY if you

A) Retain the original copyright notice B) Publish any changes you make

So you can use it to make BMS, but not sell them, but if you make changes to the design you legally must publish the changes you made or you are not legally permitted to use this design.

Frequently called “copyleft” in the software world. It’s property of the public at-large and you’re not allowed to steal it from the public.

more information

What about the non-commercial part though? “NonCommercial — You may not use the material for commercial purposes.”

I understood this part that by default under this license somebody else would be breaking the license if they were to send the design files from the github as they are to fabrication for the purpose of selling the boards? This if what I want to protect my work from.

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Must have missed that part. Edited. Thanks :slight_smile:

how do you plan on enforcing this against a company like maytech?

I would also be interested in participating in the beta program if it comes into being!

If there is a china seller that sees the potential of making money, I have little doubt that the license would actually stop them from copying the design as is and selling them, but at that point I could have a legal case against them, but I personally see the effectiveness of this being the same as trying to use your leaf blower to stop a tornado, it’s just going to at best case, change it’s course a little bit, but you’re most likely just going to lose more money in the court case than what you would be gaining.

There is actually a quite recent case where something like this happened:

Only effective measure I see is to actually remove the github page or make it private, so it is no longer directly available to the public. Thieves usually are after the easy gains. Problem with this, as the earlier statement said, the project would disappear from the public eye and would be only known for example through this forum. But this I say goes against the idea of at least sharing the idea of what you’re making and showing how it’s done. I personally have used a lot of open source projects to learn and study electronic circuits and feel somewhat obligated to give back to the community.

It is a tricky question and hard problem to solve.

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Hi @SimosMCmuffin, I read your schematics (FlexiBMS.pdf) and issued you few (not so valued) comments. :slight_smile:

Thanks for the sharing. I have some questions though :

  • Charge connectors has 3 pins. Is it in order to be able to bypass BoostDAC (e.g. in case of use of a standard CCCV charger) ? Is that not so “dangerous” if the user don’t connect to the right port ? Could it be a future improvement by adding a FET that bypass the whole BoostDAC thus letting only 2 pins on the charge connector ?
  • I can’t find the CAN chip although it’s present in the BOM.

I keep studying your schematics. Quite interesting work, a lot to learn again, thanks ! :slight_smile:

If you looked at the “FlexiBMS140418.pdf” or “FlexiBMS.pdf” they are dated on the 14.04.2018, so those are old schematics. I’ll add the up-to-date schematics .pdf of the current ones today.

@moderators Could it be possible to allow me to update the first post and the topic of this thread? They seem to have been time locked or locked by the mods.

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Ok, so I don’t go further till you upload the last version. :wink:

FlexiBMS.pdf schematic is now up-to-date

Preliminary Beta-tester sign-up opened! If you’re interested in joining the beta testing phase (if and when it might happen) you can officially list yourself in the following google sheet with some basic information.

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Done :slight_smile:

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Me too. :upside_down_face: Do you already have a cost estimate for the beta ? (could be announced by PM if you prefer).