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I'm at the point in my project where I can charge the batteries successfully, but I'm wondering if I could be using better values for the process...I'm using Leaf "Wolf" modules, a Thunderstruck charge controller, BMS, and TSM2500 charger.
My understanding from this thread is that the Leaf calls 4.1v "100%" and 3.6v as "0%". I believe the "real" numbers are more like 3.5v and 4.2v for these batteries, and that Nissan just fudges the numbers to prolong the life of the batteries without having consumers call and say "MY CAR ISN'T CHARGING TO FULL" all the time. Correct?
What's a good balancing current? What's a good voltage to set for it to kick in?
I currently have it set to 10mV below max voltage. For current, I tried 0.5A and it didn't seem to charge at all...I wound up at 3A and it seemed to do the trick. These numbers are pretty much arbitrary, though. The pack is already well-balanced, and in the end the standard deviation was .001, which seems pretty good. All cells are within 5mV of one another.
I'm wondering how this will fair when the cells are further out of sync from driving, charging, driving, charging...As soon as charging stops, the cells lose about 10mV.
Thunderstruck also has provisions for cutoff thresholds...Any value to them? In other words, if a cell hits the trigger voltage, it will stay triggered until it falls back down below a different voltage that you can set...I'm not sure I understand the value of this...
My understanding from this thread is that the Leaf calls 4.1v "100%" and 3.6v as "0%". I believe the "real" numbers are more like 3.5v and 4.2v for these batteries, and that Nissan just fudges the numbers to prolong the life of the batteries without having consumers call and say "MY CAR ISN'T CHARGING TO FULL" all the time. Correct?
What's a good balancing current? What's a good voltage to set for it to kick in?
I currently have it set to 10mV below max voltage. For current, I tried 0.5A and it didn't seem to charge at all...I wound up at 3A and it seemed to do the trick. These numbers are pretty much arbitrary, though. The pack is already well-balanced, and in the end the standard deviation was .001, which seems pretty good. All cells are within 5mV of one another.
I'm wondering how this will fair when the cells are further out of sync from driving, charging, driving, charging...As soon as charging stops, the cells lose about 10mV.
Thunderstruck also has provisions for cutoff thresholds...Any value to them? In other words, if a cell hits the trigger voltage, it will stay triggered until it falls back down below a different voltage that you can set...I'm not sure I understand the value of this...