LED lights and rechargeable battries

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rob dixon 2
18/10/2006 at 13:35
Does anyone have any experience in using high capacity NiMh batteries in LED lights?

Is the reduced voltage offset by their greater capacity?

I am aware that light output from LEDs reduces quickly in the initial phase but then hangs on for ages afterwards. I presume that somewhere in the graph showing light output against time for the two battery types, the two curves would cross, brightness being greater from the NiMhs later on. The question is, where? Are NiMhs worth using?
Steve I
18/10/2006 at 15:26
Can't much see the point in using rechargeables in LED lights. For one thing, rechargeables tend to run out quickly with little warning unlike alkaline batteries which go dimmer much more progresively (means carrying spares). Alkaline batteries seem to last for a very long time in LED lights. My front bike light is still on its original batteries and they're five years old, admittedly, I don't commute, but I do ride in the dark in winter (it's still really bright).

I just use alkalines in my LED headtorches and bike lights. Rechargeables are great for high energy gadgets such as GPS, digtal cameras, mp3 players etc.
Jord
18/10/2006 at 16:08
I use rechargeables with an LED tourch - but I agree with Steve I comments. I use a lot of NiMi batteries with my camera flash so have a few spares lying about.

If you have NiMi lying about I'd use them - there as cheap to purchase as Alkelines anyway.

The power can drop quickly and I always re charge before a weekend away or similar.
Ddyrchafedig Gyrrwr (Beic Modur)
18/10/2006 at 16:43
My main caving lamp is a specialised helmet mounted rechargable LED unit, but my back up lights that I carry in my bag are the cheap and chearful led headlights. I use alkaline in those and they last for ages. Like others have said, they are so cheap these days that I doubt that it is any more economical to buy and recharge NiMis, besides which, it can sometimes be inconvenient to recharge them, if you remember to that is!
DandyMountainMan
18/10/2006 at 17:01
This thread talked about rechargeables.

The main advantage of NiMh over alkaline is better performance in the cold. But they tend to discharge even when not in use. So not much use as a backup set. However now you can get the Sanjo Eneloop and Uniross Hybrio rechargeables that keep their charge for ages. I've been using the Hybrio's and they seem pretty good so far.
John MacEwan
18/10/2006 at 18:31
I have been using rechargeable in a Princton Tec Apex headtorch and been happy with their performance. No difference to the performance of alkalines in terms of output. Alkalines lasting a bit longer(2-3 runs rather than 1-2 runs with the rechargeables - a run being 2 or 3 hours).

The Apex has regulated circuitry so you get a good output from the start that stays constant, may be a reason why?

Steve, what kind of batteries you got in the bike light? Cannot believe there is anything left in them after 5 years! How much have you actually used them over those years?
Edited: 18/10/2006 at 18:32
Steve I
18/10/2006 at 19:19
John,

The batteries came with the bike light, a Cateye LED (can't remember the model but something like EL 200). I use it in flashing mode only. I suppose it only gets used about 20 times a year for an hour or two at a time. The batteries are branded "Sunrise Alkaline". It's got 4 AA's and that's probably why they've lasted so long. Juat checked the voltage of 1 battery and it reads 1.28 volts which is far from completely flat.
Jamie @ www.trekkingbritain.com
19/10/2006 at 00:01
I've been using rechargable NIMH batteries for the past 3 years for my camera and my LED head lamp a Tikka and now Tikka XP and they work brilliantly and would never use anything else. One advantage this time of year is that alkaline tend not to perform in coldest weather yet NiMh will carry on performing.

The most obvious advantage however has to be that there rechargable!! Why pay out for batteries and keep disposing of them when you can use the same for years!

My head torch lasts longer with the NiMh batteries and my camera lasts 4 times longer with them.
Ben Bloggs
19/10/2006 at 01:06
I've only recently started using rechargable batteries and so far I find them rubbish in my camera. They seem to make it operate far more slowly compared to regular alkaline batteries.
Barking Mad
19/10/2006 at 11:58
AFAIK NiMH batteries are typically better than alkaline - i.e. speed of output etc. - so surprised you find them slower?

Or are you using NiCd not NiMH?

Always find the high capacity 2500mah+ NiMH and a good charger have worked well compared to alkalines.

Although I would still use alkaline in a headtorch if you only use it infrequently as NiMH do discharge over time.
Ben Bloggs
19/10/2006 at 12:05
They are 2100mAh NiMH, jessops own brand. They are on their first charge, so maybe thats it.
druidh
19/10/2006 at 12:16
Depends how much you use them. Alkalines will keep a charge for ages, so are handy in a headtorch that perhaps is only brought out in emergencies. I've a little Tikka that has had the same batteries for over two years (I know they still work - I was using them on Saturday evening.

If you're using the torch regularly, NIMH makes more financial (and environmental) sense.
Barking Mad
19/10/2006 at 12:19
Give them a few cycles - plus never been a fan of own brand batteries...
Ben Bloggs
19/10/2006 at 12:45
I just went for the cheap ones as a trade off between saving my money and saving the planet.
Ddyrchafedig Gyrrwr (Beic Modur)
19/10/2006 at 23:55
LOL Ben !!!!


I like your style !



:))


Barking Mad
20/10/2006 at 09:00
... not if they are cr@p and you end up buying decent ones anyway! ;)
rob dixon 2
24/10/2006 at 14:07
Many thanks to all. For info, I used some new, almost fully charged AAAs (Ansmann 1000s) in my PT Aurora last Wed on a SAR exercise. They had had about half an hour's use beforehand. Using my search torch for the main work and the headtorch just for map reading and minor casualty handling, the batteries were so poor that I could not properly read the map by the end of the eve. Subsequent test at home on 'main beam' resulted in virtally no light after only 12 hrs. Useless! But was I sold duffs? My Ansmann AA 2600s are brilliant in my camera. Any comments???
Parky Again
24/10/2006 at 17:34
rob, how long do alkaline batteries last?

rob dixon 2
24/10/2006 at 18:02
Parky - I don't know! It's more the case of when I feel the slowly dimishing light is not worth bothering with, but I'm guessing it's at least five times longer than the above. If using itlargely for cooking and reading etc in a tent or bothy, it lasts so long one loses track of time. I'm going to test the NiMh in a conventional torch later (where alkalines last about 3 - 4 hours), to see if these are duds. Could be they're not genuine Ansmanns, or the charger is not suitable (it's a Jessops AA/AAA one - absolutely fine for AAs).
You might wonder why I went for NiMh's in view of the above. It's because of the rapid decline in brightness with LEDs - I wanted/hoped to be able to hang on to more of the initial, brighter stage. So far, what a waste of money!
Does anyone know why Petzl stopped making the Myo 5? I liked the idea of the voltage regulator and am waiting for that to be brought out in the XP or similar. What chance?
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