Tried to find this info and came up with nothing... If I have 2 unequally discharged 18650's can I put both of them in the DSD charger or should I charge them individually? Thought I read somewhere that they should be equally discharged, but I could be wrong.
DSD and Unequally Discharged 18650
- Thread starter ResQTech
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mdocod
Flashaholic
It's a single channel charger so anything you install in there together will be wired in parallel. A few tenths of a volt variations won't generally cause a major problem as they will just balance and charge up as they go. Large differences in state-of-charge (and cell voltage) could result in substantial current flow from one cell to another that could exceed the maximum safe charge rate.
mdocod
Flashaholic
If you run both in the eagletac for roughly the same amount of use, then the answer is yes, but if you use one till it's dead, and the other for 5 minutes, then the answer is no.
I've never personally tested at what point the "out of balance" condition of a pair of li-ion cells becomes a danger when they are wired in parallel. The best way to play it safe is just to pick up a DMM and check cell voltage when in doubt and only install pairs that are fairly similar in their state of charge. Or just try to plan to cycle your cells through the charger such that you usually have one cell in the flashlight and the other gets charged (remove after green for added safety, even though I have never had a DSD trickle charge personally it's never a bad idea to be extra careful).
I've never personally tested at what point the "out of balance" condition of a pair of li-ion cells becomes a danger when they are wired in parallel. The best way to play it safe is just to pick up a DMM and check cell voltage when in doubt and only install pairs that are fairly similar in their state of charge. Or just try to plan to cycle your cells through the charger such that you usually have one cell in the flashlight and the other gets charged (remove after green for added safety, even though I have never had a DSD trickle charge personally it's never a bad idea to be extra careful).
SilverFox
Flashaholic
Hello Eric,
I have found that the maximum voltage differential, with single Li-Ion cells connected in parallel, that I am comfortable with is 0.5 volts.
Tom
I have found that the maximum voltage differential, with single Li-Ion cells connected in parallel, that I am comfortable with is 0.5 volts.
Tom
The M2 is a 2-cell light, so they should be used the same length of time.
mdocod
Flashaholic
Hi Tom,
I think that's probably a pretty fair safety margin, provided the cells are of the same size.... an 18650 at 4.1V going into a charger with a 16340 at 3.6V would probably not be good for the 16340....
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Benson,
Totally missed that, excellent correction/point.
I think that's probably a pretty fair safety margin, provided the cells are of the same size.... an 18650 at 4.1V going into a charger with a 16340 at 3.6V would probably not be good for the 16340....
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Benson,
Totally missed that, excellent correction/point.
