DIY Lithium Battery Balancer and monitoring (BMS)

Yeah that looks fine to me. Im not sure if there is a different between attiny85 10su and attiny85 20su.

If you are located in the U.S I can send you some parts for cheap. I bought 500 of each resistor. Don’t think I’ll ever use all of them lol. Also have some of the other componets such as leds and capacitors.

@Jman_brosef thank you for the answer. Sorry, I live in another country. I need to get parts from AliExpress. I will tell you the current situation. If there’s a place you can help, I’d love to share your information.

I ordered pcb from lcpcb.com.
I will buy your aliexpress list and I will combine them.
attiny85 10su I know it’s appropriate for operation at low voltage levels.
Have you completed this project? Did you use the parts on the list?
I would like to use arduino yun instead of wemos mini. How difficult is it to make this change in software?

thanks in advance…

I bought some of my parts from mouser and the others from aliexpress and ebay. The parts list you posted is Joeys part list which is a better list than mine. I have completed this project.

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Again hello developers;
I’m trying to find the pieces. I just need to get it from AliExpress. I made a list below. I’m not sure I picked the right parts. are you able to check and confirm the correctness? And there are deficiencies, I can not find. Could you help me and give me the missing parts’ aliexpress links? I am very grateful to you…

Part list aliexpress;

Seems like R3 has been changed from 20k to 68k in the latest version of the github repo.

If you use an Arduino you’ll need to add a wifi or ethernet shield to get the view of the cells and do any balancing.

And I doubt the Arduino has enough RAM to do all that - additionally you are on your own with the code as you would have to start from scratch.

With the cost of a ESP it’s just not worth the effort!

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@stuart, @Colin_Hickey I `m talking about this
https://store.arduino.cc/usa/arduino-yun working on linux.

Hi everyone,

I’ve begun putting together some boards and I’m looking for a sanity check on my voltage across the ATTiny reset pin.

Measuring the voltage divider (TH1+R3 (10k + 68k) and R4 (10k)) I’m seeing 1.58V / 1.8V, which seems about right based on the resistor values, what voltage ranges will keep the tiny out of reset mode?

I should mention the voltage across C2 and C5 is both 3.3V.

Cheers!

JC

I was wondering the same, is it correct though ??

You need the voltage to be ABOVE half of VCC to avoid reset, so over 1.65V would be fine.

@stuart what do you plan to do for battery balancing?

I thought I’d just post a quick update now that I’ve successfully got three modules configured and reporting to emoncms. @stuart’s code works really well without any modification. As an experiment I tried using the Texas Instruments ISO1540QDRQ1 as a drop in replacement to the ADUM1250ARZ and that is also working well - so are the much cheaper eBay ADUMs I purchased. :grin:

I’ve documented my parts lists, some tools and notes I’ve collected along the way as a gist here: DiyBMS PartsList / Bill of Materials · GitHub

Here’s a shot of the test setup I have on my desk, without any load resistors.

Thanks for the clarification earlier @stuart and thanks for the great work so far.

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Quick update: A bunch of my parts showed up today. Not enough to get any testing done, but it’s getting close. Can’t wait!

what box is that? I like it!!

I’m hoping some of you folks will start doing some code!

What I could do with is knowing how you expect the balancing to work - manually, automatically, at top or bottom voltage etc?

@stuart I’m trying to figure out your codes right now. My specialty is php. I will do something using php. I was wondering. Where do we get the data from attiny85, which variables? I’m trying to find them. If I can get the data, I’ll start :slight_smile:

@stuart Hey stuart. Is there any difference in using the attiny85 10su vs 20su?