Couldn't figure out a good search for this question. Simply, how long will an 18650 hold a charge? I want to keep it in a dry sack in a boat for an extended period of time. I wanted a light that used primaries; DX sent me the wrong light. Before I send it back, I wanted to consider getting some 18650s. I would assume there is also a difference in maintaining charge depending on the manufacturer....since AW's have the best reputation, are they likely to hold a charge longer than the Ultrafire batteries that DX sells? Is the WF-139 the standard reasonably priced charger? They have offered me a discount on another order to make up for their mistake....
18650 newbie...possibly. Charge questions.
- Thread starter davidra
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DM51
Flashaholic
The quick answer is that if you store a Li-Ion cell cool and dry, charged to no more than 4.0V, it should keep its charge for a year.
It is better for them to be stored at a lower charge than that, and worse at a higher charge. 4.0V represents ~80% of capacity, so it is a useful amount of charge ready for use.
Please do not waste your money on Ultrafire cells - see this thread.
It is better for them to be stored at a lower charge than that, and worse at a higher charge. 4.0V represents ~80% of capacity, so it is a useful amount of charge ready for use.
Please do not waste your money on Ultrafire cells - see this thread.
cdosrun
Enlightened
Sorry, I don't mean to hijack this thread but I wondered how the discharge time would compare with unprotected cells, as they have a higher capacity and no protection circuit to power, I imagine they will last longer. I have just stripped about 15 cells from some broken laptop battery packs and am interested in the longevity of such cells compared to the protected AW for instance.
Andrew
Andrew
DM51
Flashaholic
There will be no difference. The protection circuit does not affect this at all. It just stops over-charging and over-discharging, and prevents high current drain.
The capacity of a cell is a figure put on it by the manufacturer, and some are more honest with their figures than others. For example, capacity measured at a very low discharge rate will appear higher than if it is measured at a realistic rate.
Some very cheap cells claim capacities which are totally unrealistic - for example, R123s claiming 1,000 mAh. It is not possible to make a R123 with that capacity. 750 mAh is the max possible obtainable from any R123 Li-Ion cell, and it is usually more like 600 mAh under load.
For 18650s, as here, realistic figures for capacity would be in the range 2,200 - 2,400 mAh.
The capacity of a cell is a figure put on it by the manufacturer, and some are more honest with their figures than others. For example, capacity measured at a very low discharge rate will appear higher than if it is measured at a realistic rate.
Some very cheap cells claim capacities which are totally unrealistic - for example, R123s claiming 1,000 mAh. It is not possible to make a R123 with that capacity. 750 mAh is the max possible obtainable from any R123 Li-Ion cell, and it is usually more like 600 mAh under load.
For 18650s, as here, realistic figures for capacity would be in the range 2,200 - 2,400 mAh.
