ArthurEld
Solar Wizard
I haven't charged anything yet. I'm slow. Slow and steady wins the race.
balancing strategies as they relate to BMS
- Thread starter John Frum
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John Frum
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Gazzo that is what this test rig is for.
Step 1 charge cells as a pack until one of them trips the bms.
step 2 charge indivdual cells until they trip the bms in turn.
Every seen the big Lebowski?
ArthurEld
Solar Wizard
Dude
Years ago. Maybe I should watch it again?
John Frum
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You wondered into the middle of a conversation.
I humbly suggest you read back a bit so that your contributions make more sense.
You are right and I did admit previously that maybe I didn't read back far enough. Call me the Wanderer.
Whatever Arthur is up to and for whatever reason I am totally interested. We both have the exact same power supply and cells....so I will be watching and responding. I am sure I will learn something new from his experience's.
Whatever Arthur is up to and for whatever reason I am totally interested. We both have the exact same power supply and cells....so I will be watching and responding. I am sure I will learn something new from his experience's.
John Frum
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If you are going to be top balancing, I have a bunch of methods to test.
Interested?
ArthurEld
Solar Wizard
I got every thing connected and turned on the BMS but I can't connect to the bluetooth so I still can't use the app.
Also, after my BMS turned on, I couldn't run the power supply anymore. Every time I turn on the charger it displays voltage rising then it turns off.
Tomorrow is another day.
Also, after my BMS turned on, I couldn't run the power supply anymore. Every time I turn on the charger it displays voltage rising then it turns off.
Tomorrow is another day.
ArthurEld
Solar Wizard
I contacted Michelle at Heltec and she messaged me a QR code and I downloaded a QR reader. Then I got to the Heltec site and downloaded a zip file. Then I downloaded a zip file extractor to extract an .APK file. I had to change a bunch of setting on my phone to make me a developer and allow me to use the APK to install an APP. What a pain in the butt.
I am connected.
edit- not only am I connected but I connected from my favorite seat in the house.
I am connected.
edit- not only am I connected but I connected from my favorite seat in the house.
Last edited:
John Frum
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can you post a screen cap?
ArthurEld
Solar Wizard
Here's what I set so far. I also turned off balancing. I couldn't' get it to save the calibrating current so that is set to 100.
John Frum
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looks like the battery chemistry is set to lto=lithium titanate.
Look for LFP=lithium iron phosphate.
My eyes are not good so I will probably miss something important.
The big idea is that commissioning parameters are different than the parameters for normal usage.
Will look some more later.
Look for LFP=lithium iron phosphate.
My eyes are not good so I will probably miss something important.
The big idea is that commissioning parameters are different than the parameters for normal usage.
Will look some more later.
John Frum
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power off voltage should be 2.5 volts for the capacity test.
max charge current should be whaterever you set your charger to plus a some wiggle rooom. Is that aggregate or per cell?
I can't really work from screen caps like that.
The trigger times should be very short
The resume times should be tuned to what is appropriate.
max charge current should be whaterever you set your charger to plus a some wiggle rooom. Is that aggregate or per cell?
I can't really work from screen caps like that.
The trigger times should be very short
The resume times should be tuned to what is appropriate.
ArthurEld
Solar Wizard
It's not fun taking pictures of my phone with my laptop.
I tried setting the charger to 53V and when the charger got to 53V the amps started reducing.
Now I have the BMS cell OVP set to 3.35V and the charger is set at 53.7V and 8A
I'll see if the BMS stops the charging when one of the cells get to 3.35V.
The cells have drifted from each other a little. The highest cell right now is 3.336V and the lowest is 3.326V.
So there is .01 difference.
I tried setting the charger to 53V and when the charger got to 53V the amps started reducing.
Now I have the BMS cell OVP set to 3.35V and the charger is set at 53.7V and 8A
I'll see if the BMS stops the charging when one of the cells get to 3.35V.
The cells have drifted from each other a little. The highest cell right now is 3.336V and the lowest is 3.326V.
So there is .01 difference.
ArthurEld
Solar Wizard
There is not a delay for OVP. There is a delay for OCP I set it to 5 seconds.
MisterSandals
Participation Medalist
Which of the 3 battery types is selected? I cannot see any indicator in your pic.
ArthurEld
Solar Wizard
When I picked LIFEPO4 it filled in all of the options. Then I changed some of them.
ArthurEld
Solar Wizard
One cell made it to 3.35 and the BMS over voltage limit shut down charging.
A while ago I changed the Charger amps to 12 and the BMS over current protection shut it down.
So, I changed the over current protection to 12.1
Now that I tested the BMS I will set the over voltage protection to 3.5V and charge until one cell hits the OVP limit.
edit- the lowest cell was 3.338V when the high cell hit the 3.35V limit. After about 10 min the cells are between 3.316V and 3.320V
A while ago I changed the Charger amps to 12 and the BMS over current protection shut it down.
So, I changed the over current protection to 12.1
Now that I tested the BMS I will set the over voltage protection to 3.5V and charge until one cell hits the OVP limit.
edit- the lowest cell was 3.338V when the high cell hit the 3.35V limit. After about 10 min the cells are between 3.316V and 3.320V
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