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18350

Bubble-Man

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Hello
I have a Blue Laser from Sanwu lasers, and the 18350 batteries in it keep dying,
I bought batteries of different brands, they last a week or two, then suddenly they die,
I put them to charge on my Nitecore um20 , and showing error.
Has anyone else experienced this with these type of batteries or with Sanwu lasers? Any advice?
Many thanks!
 



ArcticDude

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Well which kind / brand batteries you have?
Since you're from EU area, I highly recommend to get Keeppower or Efest batteries from Akkuteile >>
 

Bubble-Man

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The ones that just died (Charger showing EE) are Efest, the previous ones that also dies were sent by Sanwu
 

Bubble-Man

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Could it be the laser mod that short-circuiting/destroying the batteries?
 

ArcticDude

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Can't say for sure.. Are they protected or unprotected ?

EDIT:
-Also, are they flat-tops or regular?
 

ArcticDude

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Yes, I forgot to mention that my Nitecore charger does that same error sometimes with Panasonic 900 mAH Eneloops, need to change to LOW mode. (while Nitecore says under 750 mAH batteries)

20180208153115_91246.gif
 
Last edited:

WizardG

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I'm thinking these aren't protected cells. The laser may be discharging them too far. Next time you manage to charge them (or a different set) use them as you usually would but when its time to recharge them do this test first: Turn the laser on for ~10 seconds then pull the batteries out and measure their voltage with a DMM. If they measure at under 3 volts the laser is overdischarging them.
 

Cyparagon

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I concur. Sanwu... Well, most manufacturers to be fair, don't seem too concerned with preventing overdischarge of lithium cells. It doesn't happen as often with single cell designed, but 2+cell designs get tricky since the driver doesn't know if the cells are matched.

The easiest fix is don't run the laser long between recharges. The second easiest fix is use protected cells in any 2+ cell device.
 

Philipnzw

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The replies here pretty much summarized it all. Either use protected cells or Recharge more often (try to guess when the batteries are going empty). I own a pair of unprotected, flat-top Efest 18350s and I always recharge em before they are fully empty. Usually keeping them between 3-4V, as I'm quite a cheapskate and want them to last forever.

As mentioned by cyparagon, most laser drivers can't tell when a battery is going empty. It's even harder to implement such a feature in 2 cell designs. (I think most laser drivers aren't designed with this in mind at all.) It's a bit troublesome for us, but as the replies here said, just take measures to make sure you don't accidentally discharge the battery too far down.

If there are any shorts (assuming to the host), usually the entire host will heat up like crazy, as the battery dumps all of it's energy into the host, and your will notice it immediately. (I'm not sure if it can short and discharge slowly, but it's a possibility.)

Batteries are weird stuff. Unfortunately battery technology isn't at a point where we can just ignore em and make it plug and play. There's a whole lot to learn about batteries (such as them degrading quickly when under or overcharged, proper charging currents, ideal charging temps etc etc). For now we just have to baby-sit them, until a new type of battery chemistry is discovered/ new battery tech is made available.
 

Unown (WILD)

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Hello
I have a Blue Laser from Sanwu lasers, and the 18350 batteries in it keep dying,
I bought batteries of different brands, they last a week or two, then suddenly they die,
I put them to charge on my Nitecore um20 , and showing error.
Has anyone else experienced this with these type of batteries or with Sanwu lasers? Any advice?
Many thanks!
Are you saying they last a week or two with use or by simply being unused for that amount of time?
 

gazer101

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My batteries have lasted for months, but I only ever squeeze 750 mAh from them at a time (they are rated for 900 mAh, but I assume some internal circuitry is limiting that)
 




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