I am also relatively new to all this, and have done a bunch of reading. I believe that you Silverfox have a lot more knowledge that you can share that would be beneficial to the lot of us. One sentence responses are helpful, but in many respects, are not much more than a tease.
I don't have a "dischargeable" charger. I bought a XTAR WP6II as recommeded by some on this forum. It will charge from AC or 12 volt DC from a car cigar lighter. I am not inclined to buy another charger that will also discharge, in retrospect, that might have been a better choice, maybe. I do however have a number of flashlights that will discharge batteries. So along with DrScum's line of thought... I have tested some batteries relative capacity buy putting them into the same flashlight and turning it on high then I checked the voltage of the battery each fifteen minutes or so, when it got too low, I stopped the test. I then logged THAT particular battery.
Tom,
Other than suggesting buying a hobby charger/discharger would you please make some other suggestions to the average Joe who may already have a charger? In addition, do you have a hobby charger/discharger that you would suggest to someone who is just starting this sport?
Silverfox has written BOOKS
on this stuff, I am not one to herass people with a "do a search" but at least check out the One stickey at the top
http://www.candlepowerforums.com/vb...ronics-Batteries-Included-Threads-of-Interest
In this thread the item is UNPROTECTED, a cheap hobby charger will do a discharge test, even any hobby charger that can STOP at a voltage that would keep the battery within specs. Otherwise the other methods are a total pain in the butt. keeping the cell from discharging low by checking manually is almost impossible. Why? because when the cell is "depleated" it tanks fast, it does not put out much current and under load the voltage Drops fast. so at this tiny area of criticality the cell can get damaged.
In respect for the cell
either protect it, buy protected cells, or a hobby charger (even cheap) is a very logical choice. I have all kinds of Stuff for working with batteries, and my stupid $39(type) china hobby charger is the best AND the cheapest way to do a discharge, when the cell is unprotected. for a few bucks the cell can be protected, and wrapped.
If you only have a charger:
With that said, and without a discharge testing to be SURE of what you have, testing the Self-Discharge of the cell is another possibility to see if the cell is in good shape or not. In Most situation (not all) a cell that is bad or going bad, will drop in voltage in a few days from its full charge state. Rest the cell after a charge, test the voltage, then test the voltage again in 2 days. the voltage should not change by more than .01 even.
Same basic thing, the charger should stop charging. on these cells that do not reach full charge, and discharge at the high end, it can be noticed when a charger will not stop putting power in, because the voltage did not get to the around 4.2v. if a light or a meter on the charger shows that the cell isnt finishing, it might be bad.
Li-ion cells have a high acceptance of the charge tossed at them, they should not get warm when charging properly let alone getting hot. In the usual chargers that were using at normal rates, Subtract the heat that the charger might have, and the cell should be cool. any unusual heating that occurs in the cell when charging can identify one that has internal shunting. it could have been damaged from low discharge, or just too old.
All the cells that are in all the consumer products are protected, even these Were protected originally by some sort of pack protection (if it worked right
, without that protection, ya pretty much gotta know the specs, and need some sort of equiptment, anything else is a usefull Learning process