Community
OpenEnergyMonitor

Community

DIY Lithium Battery Balancer and monitoring (BMS)

bms
powerwall
Tags: #<Tag:0x00007f1be5d995b0> #<Tag:0x00007f1be5d99470>

(Brett) #771

Hi chance

what windows are you running as im running windows 10 and didn’t have any success with AVR ISP programmer
iv have one that takes the program but dosn’t communicate with the rest
my uno works with out a problem.


(stuart) #772

Yes!

Did you also “burn bootloader” - this changes the fuse settings in the ATTINY chip to make it run correctly.

Did you also select all the correct options in Arduino IDE (like chip type, speed etc.)


(stuart) #773

You may run into problems in very cold environments - resistor R4 increased in value to 20K.

If you do run into cold problems (and the BMS unit goes off line) a simple “fix” is to twist the thermistor legs together to short it out. You won’t get temperature readings then, but you can untwist it when the weather warms up!


(Brett) #774

i have one module that is about 4c lower than all the others and when sending command to that module it drops out all together taking out the hole string.
this one module is the one that is creating problems with making the ESP8266 d1 mini to drop out.

But if there is no battery power to this module the communication still pass through to the hole string of modules.

D4 just flashes like its in reset or waiting for a command is this normal but now the module not showing in the string have replaced the thermister 3 times still the same thing led just blinks like its in waiting mode or something.

thing is we are in 27c to 45c here and not even in winter coldest i get would be 6c but we are in summer now.
Haven’t got to fully test my bank yet till all the bugs are sorted out.

Unless i have a bad ADUM1250 on the 12module which wouldnt surprise me being from china but the module 2 with the temp and nolonger working but flashing module got me stumped


(Dirk Walde) #775

I also had three defective or problematic NTC just install a new one and solder it cleanly to the top of the board !!!

My default setting for the NTC is at Attiny 1.00 not 1.08 for the values.
I changed that directly in the attiny code (.ino)


(Chance Schraeder) #776

Brett:
what windows are you running as im running windows 10 and didn’t have any success with AVR ISP programmer
iv have one that takes the program but dosn’t communicate with the rest
my uno works with out a problem.

I used MacOS, I saw that Windows has issue. Now that I think about it, I believe it was your post that warned me of this. haha!

stuart:
Yes!

Did you also “burn bootloader” - this changes the fuse settings in the ATTINY chip to make it run correctly.

Did you also select all the correct options in Arduino IDE (like chip type, speed etc.)

Yes, I believe so. Well at least I tried a few times with the Uno and it confirmed. I recall trying on the USBasp as well and outside of clock frequency warnings everything appears to have worked correctly. I read that Chinese asp’s tend to say that and to ignore it.

I set all the parameters you defined in the sketch such as 8MHz internal clock etc.

So that makes me happy to know that I didn’t mess everything up. This is my first attempt at soldering and programming micro controllers.
Next up is to finish the programming the sketch on the boards and get these pull up resisters soldered to the WiFi thingy. :stuck_out_tongue:


(cfreak) #777

i can’t convince myself to give the pan soldering a shot, so i’m wondering if anyone cares to sell me 12 complete boards :slight_smile:


(Brett) #778

if you have gas or electric element, i do say gas is more easier to control on a frying pan


(Vela Nautica) #779

it is not that hard with the pan. do one at a time on a sheet of aluminium foil.
after 60 sec the solder paste starts to melt, eventually you need to push some components in their final position at that time.
the worst part was to dose the smalest amount possible of solder paste…
:grin:


(stuart) #780

You can still hand solder - my demo was purely for educational purposes!


(Dirk Walde) #781

Would it be possible to use DS18B20 temperature sensors on the Attiny85 board or on the ESP8266 instead of the NTC 10Ohm. Without much effort.


(stuart) #782

No, theres no PINs left on the ATTINY - possible on the ESP but a reasonable amount of effort.


(Chance Schraeder) #783

Sweet success! First module provisioned.
Big thanks to everyone here contributing to this project.


(Qing Miao) #784

Hello, I just watched every video from Colin, and read the git, however, I am still wondering, will the system function as a capacity monitor? I understand, it can measure the voltage, and hour, but with balancer, the output of each battery may differ. Is that right? is there any formular from the sensor readings lead to the measurement of mAH of each cell in every discharge loop. Thx


(Dirk Walde) #785

You have a R1 2ohm witch Fuse du you use ? 2A or 3A


(Chance Schraeder) #787

I lied 2amp :frowning:


(Chance Schraeder) #788

What are your guys thoughts on installed small 30-40mm 5v fans in parallel with the discharge resistors?


(stuart) #789

No it cannot measure capacity as it doesn’t know about the power drawn from the battery pack.


(stuart) #790

Don’t forget fuses are optional - you could use a piece of wire and bypass it - although obviously be careful if you do this. Any problems will then destroy the board/copper traces


(Joey Poortman) #791

Depending on the space the whole system is in it couldn’t hurt, but i think a good 12v fan would be better. Even at 4v they displace more air!