Capacity Testing

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theDIYHobbyist

New member
Joined
Feb 10, 2017
Messages
3
Hey guys, I've got a newbie question that Ihope someonecan answer for me. I apologize if this has been discussed elsewhere, please link below if it has.

So my question is this. Should there be a difference between discharge mAh and charge mAh?

I am Cap Testing my cells with the Foxnovo F-4S (Opus is in the mail), and I've noticed there are differences in the two capacities. I set my good cells in the charger and I let them do their thing. Then I come back an hour or so later, while it's in its discharge, and see that some or all of the cells are sitting at 2100-2400 mAh. This pleases me, so I go back to doing whatever. A few more hours go by, *beeep beeep* *beeep beeep*. I walk over to the charger, Sharpie in hand, just to find out that the cell only charged to 1521 mAh.

Now in my head, I would think I would care more about the discharge capacity than the charge capacity, but that's me. I also know there is very little operational/reference literature on the current charger I'm using. Short of camping out at the charger, or installing a CCTV system to monitor the charger, is there a way to see the discharge capacity after the fact?

Any information would be appreciated and I thank everyone in advance.

Nick
 

daromer

Moderator
Joined
Oct 8, 2016
Messages
5,659
Hm You say you "come back when they sit in discharge"
Are the discharge cycle done or not? If not that value cannot be the discharge itself since its not done

In general a charge should be a couple of % higher than the discharge.
BUT
It all depends on the tester. How the algoritm is set to do the test and how its measure.

For instance it can be that end current on discharge is 100mA and at 3v meanwhile the charge ends at 4.2v and directly when it hits that 4.2v at 1A. If this scenario is true then you would get numbers like above since a stop when it hit top voltage will not charge it up more than to 75-80% at most!

Thing is i have not tested the Foxnovo myself so i cannot tell how that charger works. And i dont have the time to try to get a manual and read up on it either im afraid :)

If you leave above batteries to be for a couple of hours. What voltage does it settle at? It it goes way below 4.1 the battery isn't fully charged at all....

I hope someone else fills in on that particular charger or if they have more tips.
 
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