my 18650 battery doesn't last long in dereelight?

[picard]

how come my 18650 battery doesn't last long in my deerlight? I have the tenergy battery. I put in fresh battery a day earlier but I never turn on the light. when I took my dog for a walk for 15min, my dereelight last only 10min on high. it shuts off.

I have to turn it on again. Does anyone have similar problem?

 

[VegasF6]

Well Picard, the first questions that come to mind is how does the battery work in other lights? What are you charging it with, how old is it? Voltages before and after? Which module is it exactly and what is the current draw at the tailcap?

I ain't beating up on you or anything, but I don't see how anyone can help without more info

 

[picard]

Well Picard, the first questions that come to mind is how does the battery work in other lights? What are you charging it with, how old is it? Voltages before and after? Which module is it exactly and what is the current draw at the tailcap?

I ain't beating up on you or anything, but I don't see how anyone can help without more info

I have the DBS V2 black color. the batteries are fresh. I bought them only 5months ago.

 

[mdocod]

VegasF6 is right, the only way we can offer any solutions or ideas or explanation is with more information. We need to know what voltage the cell is coming off the charger, what charger you are using, ideally what module you have in your DBS, and ideally also what voltage the cell is when you take it out of the flashlight after is has "gone dead."



Eric

PS: you mentioned you bought the batteries 5 months ago... have you used them since you got them for anything? did you charge them when you received them? did you use them in a flashlight after receiving them, discharging them, and then leave them sit for 5 months? There are all sorts of reasons your runtime could be suffering.... answers to any of these questions will help lead to some more answers to your problems

 

[yellow]

while they are "new", they could have been produced some time ago.
Being used or not, Li-Ions are considered to give a useful life of 5 years, no matter on charging cycles.

Could also be the runtime accumulated in this long time is not remembered correct
(just happend to me)

--> charge it and try runtime again,
compare both

I have to turn it on again.

Sorry, I missed that.
Do You mean it works then? For the runtime it should?

 

[VidPro]

also . . .
check for heating when charging, and check for self discharge, IF those things are happening , then that is very bad.
Like . . .
check it when its charging, on most chargers there should be little to no heat comming from the battery, BECAUSE a good li-ion converts most of its charge to storage instead of wasting it as heat. also because it is not allowed gas pressure and heat for end-of-charge cutoff, it should not be getting hot at all, like a ni-?? might.

to check QUICKLY for self discharge, without wasting a lot of time. after charging, let it sit for 30min to 1hr, then put a simple voltmeter on it, and see if the voltage droops down when checking. most Meters dont put much load on the battery, if its visually going down in voltage after charge (and rest), then it could very well be very bad. If your meter puts some load on the battery, then check it in 15-30min intervals instead, and see if the voltage is going down.

a light with (only) electronic switching, can potentially discharge a battery, but that takes more like a MONTH.
i had One cheap light , that the electronic switching curcuit failed over TIME, and it began to discharge the battery faster and faster.
i spotted THAT problem, by putting the light (without the battery) on the bench power supply, which showed how much drain there was when connected like a battery.
You could also check that same thing, by putting a Ampmeter between the tailcap connections and the battery (depending on the light) making the last connection with the ampmeter, then when your sure its not reading AMPS switch to the miliamp or pico amp scale, and see what the draw is on the battery when in the light without the light on.