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Rechargeable flashlight battery question??

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I have three Fenix PD35’s 1000 Lumens, and a Streamlight ProTac HL 5-X USB 3500 lumens. All use 18650 rechargeable batteries. I use the PD35’s all the time, I have one on me and the others laying around. I charge them every couple on months and have never had one go dead. The Streamlight rarely get used unless I need to light up my whole yard, so I haven’t charged it as much.

Two months ago I went on a camping trip and charged them all. The Streamlight was dead, but I didn’t think much about it because it hadn’t been charged in probably three or four months. Yesterday I went to use it and it was dead again, hadn’t hardly been used in two months. I put the batteries on the charger and they showed 60-80%. I thought the light might be faulty, but I charged them overnight and it worked fine when I put them back in.

So I wonder what’s going on? Could it be that with 3500 lumens it requires nearly a full charge to even light the light? Or could the light be defective?

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A chemical battery will develop a chemical bubble, the old NiCad batteries were notorious for it. If you did not completely discharge and then completely recharge would develop a chemical bubble and would only use that much of the battery. I am sure all chemical batteries have the same function lithium-ion is not near as susceptible to the chemical bubble but it does happen.

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  • 2 months later...

Like all batteries even the rechargeable type, and I've got a Fenix with a battery that charges with a USB port, and another Fenix that uses a charger. The one that uses a charger is probably 5yrs old and I recently had to buy one battery for it about 2 months ago. I don't use it as much as the other smaller one so I think that batteries shelf life just ran out. At least that's what I think.

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  • 3 months later...

I use to manufacture lights for a few of the major brands the best practice when storing lights for long term is to fully charge the battery and turn the tail cap half a turn so the light will not function. 95% of the flashlights on the market still draw current like your cell phone when it's off.

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  • 4 weeks later...
Posted (edited)

I have the HL-5 X also but I have not experienced the the battery problem.  It mostly sits charged up. Every once in a while I click it on and it lights up light like the sun.  
I keep the streamlight 18650 in a cheap Chinese eBay light and no issues with that one either. It gets used a little more often but it doesn’t seem to have any issues maintaining a charge. 

I have an old surefire G2 with a Malkoff led in it and another streamlight 18650 use it fairly often and it maintains a charge too.  

I wonder if you have a couple bad 18650s?

Edited by kentmck
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