Xtar Dragon, which capacity?


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bbbbrass

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Jan 17, 2022
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Hello all, I've searched and haven't come up with the answer so I'm hoping there is some insight out there!

I have 3 Xtar Dragon 4 chargers, and also 1 VP8. The Dragons list both a charge and discharge capacity, the VP8 only lists a single number. would you use the charge or discharge capacity to record for your cell?

Charge is almost always the higher of the 2 numbers, and I check IR separately.
 

Korishan

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Jan 7, 2017
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Always use the discharge value. The charge value is generally useful for finding cells that are self-dischargers/heaters. If a cell gives off 10W of heat, then it will be very noticeable with the comparison between charge/discharge values.

However, when sorting cells based on capacity, always use the discharge value as it's more accurate.
 

bbbbrass

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Joined
Jan 17, 2022
Messages
51
Always use the discharge value. The charge value is generally useful for finding cells that are self-dischargers/heaters. If a cell gives off 10W of heat, then it will be very noticeable with the comparison between charge/discharge values.

However, when sorting cells based on capacity, always use the discharge value as it's more accurate.
Appreciated! That is what I was thinking. Of course, I wish I had thought of that before I recorded values of a few hundred cells.... Would you think if there is a significant delta between charge and discharge values that is a red flag? If so, what % difference would concern you?
 

Korishan

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If a cell is charge capacity of 2000mAh, and a discharge of 1800mAh, I would consider that too much of a difference, imho.

However, I have no real idea of what would be acceptable. The charge/discharge should be very close to each other on a good cell. I am guessing about 100mAh at the most.
This is where the IR would make a big difference and help out a lot.
 

bbbbrass

Member
Joined
Jan 17, 2022
Messages
51
If a cell is charge capacity of 2000mAh, and a discharge of 1800mAh, I would consider that too much of a difference, imho.

However, I have no real idea of what would be acceptable. The charge/discharge should be very close to each other on a good cell. I am guessing about 100mAh at the most.
This is where the IR would make a big difference and help out a lot.
Every cell for power wall is being measured with an RC3563 and checked against Wolf’s database. Only using cells with good IR and over 80% capacity. I’ll check my ones closer to the margins to be sure of discharge capacity.
 
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