Fireflies ROT66 dimmer than it used to be

I bought a first gen Fireflies ROT66 with the Nichia 219b leds over 2 years ago, thanks to all the useful reviews of it. It perfomed fine, even my mother in law liked the light from it and she isn't into torches, just appreciated the light quality and brightness.
However recently it has stopped doing turbo after double clicking, doesn't ramp up so high and the lights on the on off switch are currently 2 rather than 4.

So I was wondering if anyone had any idea what the problem is. Are the batteries getting a bit old? I have 2 sets and swap between them. Or did letting the teenagers take it outside and drop it in some mud late last year maybe do something to it?

I would test the voltage on the batteries after you charge them as either they aren't getting charged fully or maybe the batteries have developed high internal resistance.

I forgot to say, they were doing 4v when freshly charged, but I just have a normal multimeter and don't really know how to check much more than that. It's a while since I last read the forum much.

guthrie said:

I forgot to say, they were doing 4v when freshly charged, but I just have a normal multimeter and don't really know how to check much more than that. It's a while since I last read the forum much.

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If your meter is accurate then your charger seems to be working. Does the indicator on the light show full when you put freshly charged batteries in it and did you measure the voltage when it has 2 bars? It is possible that over time the batteries either got damaged and/or lost a lot of capacity and maybe even developed high internal resistance making the unable to deliver higher amounts of current. I once has a similar incident where I would charge a battery and put it in a light and when I tried it the light dimmed and when I checked the battery the voltage had dropped significantly way below "full" charge.

I'll try that at the weekend thanks. Maybe I do need new ones, off to the battery section....

guthrie said:

I'll try that at the weekend thanks. Maybe I do need new ones, off to the battery section....

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It is possible for sure. Me and many others here know that there is many variables in using rechargeable batteries that have them lasting a long time in use vs failing quicker than expected. You can have mediocre to bad chargers, low quality batteries, overdischarging batteries in use damaging them, excessively high current on batteries that are at the limit or beyond their specs and so on. I'm no expert on batteries but if I had a light that took 10A I would want to get a battery that was made to run at 20A for it as I think that would increase my battery life in years in service but may be at an expense in runtime perhaps. You could use an adequate battery and save a little money on cost perhaps and replace it more often that is a calculation I'm not up to.

WEll I have got a proper nitecore charger, but I do appreciate after a couple of years there is bound to be a fall off in the internal chemistry.