In the past months @jtag worked on a smart programmable bms capable of high current flow (check theoriginal threadfor specs). He shared every single step on github and he did it for free.
Unfortunately he doesn’t have time to carry on the production but he left all the necessary for someone else to do it. I didn’t want this project to be buried in the forum so I contacted several (tens) factories and came up with this:
Prices
In the spirit of the original project I will handle all the production, payments, shippings totally nonprofit. My calculations for a 20pcs batch are the following:
pcb factory+ pick and place robot labour+ metal stencil factory+ BOM+ shipping to my home+ 24% VAT and duties= from 90 to 110€ (this oscillates because of components prices) for a complete, fully assembled product.
I will ask you to make a “mandatory donation” of 10€/bms to @JTAG paypal link (if he wants to provide one ) .
Quality
PCBs: FR4; 2oz copper on inner and outer layers; gold immersion; “flying probe” testing.
Industrial metal stencil: laser etched; medium thickness stainless steel.
Automated assembly: lead-free; carried out by these machines: YS24, YS12, YV100XG, Heller reflow oven; AOI testing.
BOM: of course I will provide the factory with original components sourced in Europe (for ex. Wurth) and in China.
a little help on the firmware please…
To be honest I don’t have any idea on how to upload the firmware on the ICs. I would truly appreciate if somebody experienced could make a step by step video, so that me or a chinese guy at the factory can make the hardware working.
1 week for pcbs, 1-3 days for automated assemby, 5-10 days for shipping to me+ customs+repacking. BOM gathering is not predictable yet, probably less than 2 weeks (this can be done at the same time of pcb manufacturing).
I’m not jumping on this one because I’m pretty broke and don’t need a bms right now, but I can tell you that fedestanco works very well with these group buys/non or very little profit productions. I bought from him and he knows what he’s doing, if any of you is hesitant because of the recent problems happened on group buys, don’t worry about this one. Good luck, this is a great deal!
Few specs from the original thread: up to 12s (4,2*12= 50.4v); technically up to 140Amp, tested up to 100 if I am not wrong.
I dont loose or gain anything if this GB reaches the goal or not. However this is the “vesc of BMSs” so the winners will be the buyers and the community itself .
You can still make it yourself and have fun doing it! I am just bringing an “open source pro-manufacturing” probably for a lower price .
It uses STM32F303 microcontroller, you will need STLink ( programmer ) to upload the firmware.
You can use ST-Link V2 Utility ( software ) to upload the binaries and verify the contents of memory.
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