building a small pack to play around with. using battery hookups molicell medical pack 2200mah cells. i have about 50 mixed cells (LG, samsung) with similar capacity to the 50 pieces of identical molicell. i planned on mixing them together and matching capacity in each pack. looking at the molicell cutoff voltage kinda bummed me out. my mixed cells cutoff at 2.7 while molicell cutoff at 3.0. would i set my 100 cell pack to cutoff at 3.0? this would increase life span of my mixed cells but im guessing cutting off at 3.0 would reduce my total runtime. so hypothetically 100 mixed cells cutting off at 2.7 gives me 100ah. does this mean 100 molicell cutting off at 3.0 would give a reduced capacity battery of lets say ~75ah? id rather not tear apart another 75 of these packs to achieve the desired capacity. any advice is appreciated!
understanding low voltage cutoff vs. capacity
- Thread starter texfixdfw
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OffGridInTheCity
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If you look at the discharge curve - its almost vertical at 3.0v/2.7v. This means that there's no significant power at 3.0v or 2.7v - e.g. it just doesn't matter in the real world of powering anything. The low for 18650 lithium-ion is more 3.4v-3.5v - e.g. the 'knee' of the discharge curve.
I would not only make sure the packs have same ah count but that you also evenly distribute the different cell types among the packs and make sure IR is reasonable all around
I would not only make sure the packs have same ah count but that you also evenly distribute the different cell types among the packs and make sure IR is reasonable all around
oh the visual is amazing, and makes sense why i couldnt find any info on this. kinda moot to worry about any 18650 below 3.5v. so im understanding that the low cutoff recommendations are for purposes of not over discharging/degrading lifespan. usable voltage is same for both of my mixed and moli. thankyou sir!