Thread: Low cost BMS
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Old 11-30-2014, 07:14 PM   #125 (permalink)
Astro
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Quote:
Originally Posted by 4Springs View Post
I have posted details of my component purchases on the Sourceforge website (look under Files -> Components). Modules were about $4 each, Master about $50. These prices are parts only without the board itself and without the PIC microprocessors.
I managed to do my cell top modules for AUD$3.66 each (including PCB, components, PIC micro and all shipping to Australia).
I used Diygsm they made very nice boards and shipped via DHL with a tracking number. They double checked the files i sent them and let me know when something wasn't quite right.

I don't have the figures for my master boards but i would estimate less than AUD$10 each. The masters PIC chip was USD$1.72 compared to the cell tops AUD$1.32 PIC chip.
The master PCBs were AUD$2.40 compared to cell tops AUD$0.98 per module.
The only other significant difference would be the voltage conversion chip and the LCD.
I can't remember what the voltage conversion chip cost but it wasn't much and the 16x2 line LCD was AUD$2.25 from eBay. I upgraded my LCD to the 20x4 line version which costs AUD$7.23.

There are other expenses like solder paste that i haven't included.
Mainly because i made over 50 cell top modules and 3 master modules and still have heaps of paste left in the syringe. So it will be a shared expense over many projects.

So i think the BMS really does live up to the threads title of "Low cost BMS".
When i was shopping around for a BMS system i was seeing commercial cell top prices around $14 with the master module with display around $250.

Commercial 48 cell system = $922
Low cost BMS 48 cell systems = $185

It all depends on how you value your time, if you are comfortable with DIY and how much satisfaction you get from knowing you did it better and cheaper yourself.
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