SUNWAYMAN V20C 18650 battery question (safety related)

acs55812 · Oct 15, 2011

Some 18650's have flat/smooth ends---others have a "normal" raised end for the positive side, which I think these may have some safety circuitry built in also.

My question is for this light---is the safety circuit built into the light or does it need to be built into the battery itself

The reason I ask is I have an ample supply of the flat style non-protected 18650's from laptop batteries that I would like to use---however I also don't want to blow anything up!!! (like my leg when this is in my pants pocket!)

Kilted · Oct 15, 2011

I also have a good supply of unprotected 18650's, I would like to know also. In the past when the light no longer goes into highest brightness I would just change out/charge the 18650. Like Surefire U2, when level 6 was gone I knew it was time to change the battery.

=D~~ Kilted

jh333233 · Oct 16, 2011

Non-protected cell are safe from overdischarge for 1 cell light since there would be an obvious dim when the battery cant give out enough current, then you should charge it

candle lamp · Oct 16, 2011

I know there is no safety circuit in V20C to protect 18650 from over-discharge. But you can just charge the battery when the light become dim.

Lou Minescence · Oct 16, 2011

The safety circuit needs to be built into the battery.

The battery 'safety circuit' will protect in 2 ways, Over discharge and short circuit of the battery. It is built into a 'protected' battery.
If an unprotected battery with no safety circuit is run down below a flashlights operating voltage range, the light will dim or act strange. At that point you should stop using the battery to avoid further discharge or damage to the battery. There will be no short circuit protection.

2100 · Oct 16, 2011

In very rare cases where the drivers fail (MOSFETs die due to high temps after cycles and cycles of high temperatures), it would cause a dead short. In that scenario, the PCB would protect your cells from venting. However some good unprotected cells would not vent even in a "short" of maybe what 10-20A? The tailcap spring provides some sort of resistance.

Panasonic NCR18650A
http://www.youtube.com/watch?feature=player_embedded&v=ErKyND4_Gf4

BTW, those are 14 awg wires, so pretty beefy. And the best thing is, the NCR18650A still work as if nothing has happened.... (the cell is used in Redilast/AW)

jh333233 · Oct 16, 2011

2100 said:
In very rare cases where the drivers fail (MOSFETs die due to high temps after cycles and cycles of high temperatures), it would cause a dead short. In that scenario, the PCB would protect your cells from venting. However some good unprotected cells would not vent even in a "short" of maybe what 10-20A? The tailcap spring provides some sort of resistance.

Panasonic NCR18650A
http://www.youtube.com/watch?feature=player_embedded&v=ErKyND4_Gf4

BTW, those are 14 awg wires, so pretty beefy. And the best thing is, the NCR18650A still work as if nothing has happened.... (the cell is used in Redilast/AW)

1hr and still 3.7v??

SUNWAYMAN V20C 18650 battery question (safety related)

acs55812

Newly Enlightened

Kilted

Enlightened

jh333233

Flashlight Enthusiast

candle lamp

Flashlight Enthusiast

Lou Minescence

Flashlight Enthusiast

2100

Enlightened

jh333233

Flashlight Enthusiast

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