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DIY Lithium Battery Balancer and monitoring (BMS)

bms
powerwall
Tags: #<Tag:0x00007f10a4e8ed18> #<Tag:0x00007f10a4e8eb10>
(Jman Brosef) #854

Can I connect other devices the the i2c line?

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(stuart) #855

Its the same code, just change the device type in Arduino and upload!

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(Jman Brosef) #856

It doesnt compile for me. It can’t find userinterface.h

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(PetrN.) #857

5 weeks I’m waiting for 85V-10SU … :frowning: No more.
I made 15x DIYBMS with 85-20SU …
14x works as they should … :wink:

2 Likes

(PetrN.) #858

And the next day they’re working …:wink:

Thanks Stuart !!! Good job! :slight_smile:

Another 14x will follow when 85V-10SU arrives.
I compare how they work

5 Likes

(stuart) #859

Very neat install there - a lot of power!

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(Tim Nachbauer) #860

Hey, I recently finished all my seven BMS PCB modules and got them connected to the ESP. I can see the voltage of all the cells in the web interface and if I click “Above average balance” the BMS modules start to balance my battery. The only problem is, that the module connected to the pack with the highest voltage (the last time I tried it was 4.2V) doesn’t discharge them. Right after I click “Above average balance” the blue LED lights up, but after 2 or 3 seconds goes out with a surprising fade out. Did somebody have the same problem and knows how to solve it? Do I need to replace a specific electronical component of this board?

Thanks for any help
Tim

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(Johannes) #861

Hey guys,

I am very impressed about the process of this project. Some years ago I checked online for a solution for my batterys laying around. Found this but was still in the start. Thank you for that.

Is there a one layer pcb version? As I have access only for a CNC-Mill and not enough expertise/time to work with kicad or ordering pcbs. I was trying to find a simple one in the github rep. If someone has a file which is ready for CNC I would appreachiate.

I would like to build (but not to design) a single layer - “non smd/ as less as possible smd” - version.

thank you for now.

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(stuart) #862

Hi, there isn’t a 1 layer PCB version. Ordering PCBs from the China shops is so easy and low cost - its just not worth milling your own PCBs. The Gerber files are in GITHUB - no need to even open or install KiCAD on your PC!

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(Johannes) #863

Hey,

Am sorry to not answer your question, but I would like to ask if you could share the boardlayout with me. On the photo its look like a single layer layout which I am looking for.
Thank you.

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(Johannes) #864

wow stuart thank you very much for your fast response. Even if its not exactly what I wanted to hear. Its always impressive to have a contact with the brain behind the project. There is a user post with a photo just some posts away and its look like a single layer design, maybe he can share it. As it is also smd there would be still some modifications to do for me.

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(Thássio Lima) #865

Hi,
So this board was made with the Proteus program, there are some changes from the original circuit:

  1. The power supply part with the REG710 was replaced by a 3.3v linear regulator.
  2. The mosfet was replaced by an NTMFS4935N taken from motherboard.
  3. The isp connector has been removed.

comments:

  1. If the linear regulator is used it is necessary that each module has an isolated external power supply.
  2. There are three pins available on the board to add a 3.3v buck/boost module, this excludes linear regulator and external power.
  3. The module was made by thermal transfer method with paper.
  4. I do not know if Proteus exports files to cnc machine.
  5. I am no longer using these boards for lack of connectors and cables, I ended up ordering the stuart boards.

buck / boost converter module mentioned.

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(stuart) #866

Just a comment obviously this is not my design, and using a linear regulator will mean this module will stop working when the battery voltage drops to about 3.5v, so not a good choice for a BMS.

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(Thássio Lima) #867

Yes, as I said the regulator was placed until the buck/boost module arrived from china, the regulators were powered with 8v from an external source.

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(Brett) #868

Hi stuart
BMS is running great the past few mounts with out a problem.
Looking at adding a current sensor hall affect sensor in the system

50A/100A/150A/200A Bi/Uni AC/DC Current Sensor Module (arduino compatible)( eBay item number:111689533182)
been sitting on a wemos D1 + wifi waiting on my current sensor to come.

Is it possible to run the bms and current sensor via the wemosD1 + esp32 with some code modes?
As i know the D1 is much faster than any processor on the market.

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(stuart) #869

What current sensor is it? There are plenty of spare CPU cycles left in the old ESP8266 for monitoring things like this.

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(Brett) #870

i have the wemos D1 mini esp8266 not bad but has a tendency to not respond.
be great to add in to the charge status of batteries and voltage going to the cells along with bms balancing.

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(Andy) #871
Summary

Are the V3 boards still available, i not sure if it would be cheaper to buy new due to postage to Australia. How do i private message you.

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(Odysseas) #872

Hi Colin
Is there any way we could have a soldering paste stencil for the version 3 pcb because I cannot find the file anywhere.
Thank you

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(Brett) #873

Hi andy

I live in Brisbane Queensland and cost me around $35-+ for each module to build myself after a few boards failed.

If you need a solder paste screen printed let me know i have a 3d printer now wouldnt be a problem printing you one

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