jbd / overkill bms - state of charge

smoothJoey

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Since I only charge to 3.41 volts the current accounting never resets.
It drifts lower by ~1.5ah per charge cycle.
Not a problem because I have an hall effect sensor based battery monitor which is accurate enough for my application.
 
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squowse

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Since I only charge to 3.41 volts the current accounting never resets.
It drifts lower by ~1.5ah per charge cycle.
Not a problem because I have an hall effect sensor based battery monitor which is accurate enough for my application.
Id be happy enough if it reset at the top or bottom. It's just resetting itself in the middle. I'm going to leave it alone and see what it does. When the parameters are changed it resets and uses voltage estimation.
 

smoothJoey

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Id be happy enough if it reset at the top or bottom. It's just resetting itself in the middle. I'm going to leave it alone and see what it does. When the parameters are changed it resets and uses voltage estimation.
Have you manually reset it at the top?
 

MrM1

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Yeah I like some of the features of the IOS version. Like you can calibrate the cell voltages to a meter, you can not do this with the Android app, but not sure if can do the reset of the amp hour / % of charge or not. Im going to take mine home here in a few and check it out
 

curiouscarbon

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anecdotally, the JBD 120A 4S BMS i use only seems to report 0.0A or 0.5A but rarely anything in between.

this quantization error surely causes some amount of the drift in coulomb counting mode.
 

MrM1

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Unless the "reset" button in the middle of the page does it, it looks like you'll need the pro version of the ios app
 

MrM1

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Just got them pro version. I am definitely not as good impressed with the ios version
 

MrM1

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The android version has this setting that resets the battery percent used to what ever the amp hour used is based on your capacity.

It's handy to sync the capacity when the amp hours are full.

Capture+_2021-10-27-22-04-15.png

Capture+_2021-10-27-22-04-39.png

Capture+_2021-10-27-22-04-54.png
 

Isaac-1

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This all leads to the question of what is the proper way to do a charge cycle on these batteries to get them to switch to method 2?
 

squowse

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This all leads to the question of what is the proper way to do a charge cycle on these batteries to get them to switch to method 2?
Did you read the pdf? It seems to be saying that a complete charge, complete discharge followed by a complete charge should do it.
I still struggling 🤣
 
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