Part of a three part poll on Speleotechnics see posts in Equipment/lighting

Humph. I had the pleasure of caving entirely on my Mini Q40 on Saturday after my 14 LED FX-Ion packed up (again) before i'd even got off the ladder down Garlands.

:cuss:

I've not used a Speleotechnics lamp since the FX2 came out (early-mid 80's). That lasted for years and I only stopped using it as my main light when I switched to carbide. In fact it still worked last year when I charged it up - for 5 hours or so anyway. Not bad.

By the way, Phil Brown (Caving Supplies) was saying the other day that these units you can buy to take duracell "flat" 4.5v batteries for the FX Headlite will soon knacker the LEDS (if you have the 7 or 14 array) as they are rated at a voltage which is less than the Headlite battery of FX3 and using 4.5v is bad for them He has ahad a few returns.

thats interesting, quite a few people in know (including myself) have put a 7 led reflector in an oldham cap lamp with a petzl zoom 4.5 v battery pack mounted on the back of the helmet. Not heard of any probs yet. I dont use it that regularly - only on trips that I know are going to be knarly and tight. Many people are using them on expeditions either as a back up for their carbide or where you cant get power to recharge lamps (a pack of 5 or ten flat pack batteries would easily last a month).

In what way would the LED's be 'knackered'

LED's can be pretty easily knackered by too high a voltage, but its not hard to use resisitors and voltage invertors (if such a thing exists) to regulate the voltage is it? Several people i know use oldham with 7LEDS and 4.5 V battery and have no probs.

The issue is that NiCad and Lithium-Ion cells are 1.2v each, FX Headlight, FX Ion and FX3's all have 3 cells = 3.6v. I dont know what voltage the 7 LED arrays are designed to run at, but if it is 3.6v, then using a 4.5 volt flatpack or 4.4 volt Oldham (lead acid =2.2v per cell) will over-run them by 0.8-0.9v. I have heard that over-running LED's shortens thier life but I do not know how much you have to over-run them to have a significant effect.
If you are worried about it you can fit an adapter into the battery pack, petzle do one, and use three AA NiCad's. This will shorten run time, each AA NiCad rechargable cell is normally 300mAh x3=0.9Ah, 1amp bulb will run for 0.9 hours, 0.5 amp bulb will run for 1.8 hours. A way around this is to use more industrial NiCad's with a greater duration.

When all is said and done a little it of thought and fiddling with Oldham headsets, LED's and battery packs gets you a well tough useable light solution and is better than spending £100, £170, for a badly made Headlight or FXIon.

Not that tough though





:injured:

SamT said:

In what way would the LED's be 'knackered'

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As in "don't work anymore"! At least that's what Phil Brown said.

Huw Groucutt said:

LEDs can be pretty easily knackered by too high a voltage, but its not hard to use resisitors and voltage invertors (if such a thing exists) to regulate the voltage is it? Several people i know use oldham with 7LEDS and 4.5 V battery and have no probs.

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People who make/sell lamps and people who know about electronics constantly tell us that driving these LED clusters from 4.5V flatpacks will shorten their lives or blow them. However, stacks of people across the country are doing it every weekend and and have been doing for a few years now - I've not heard of any failures. Theoretically it may well be a bad thing to do, but in practice it seems to work fine.

Rhys

Rhys said:

People who make/sell lamps and people who know about electronics constantly tell us that driving these LED clusters from 4.5V flatpacks will shorten their lives or blow them. However, stacks of people across the country are doing it every weekend and and have been doing for a few years now - I've not heard of any failures. Theoretically it may well be a bad thing to do, but in practice it seems to work fine.
Rhys

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Fair enough - I am only passing the message on.

You've not heard of failures, but if you sell the damn things (as did Phil Brown) and irate people are knocking on your door demanding their money back waving dead LEDs under your nose, you tend to have a different perspective and believe that there might actually be a chance that there are some failures...

underground said:

Humph. I had the pleasure of caving entirely on my Mini Q40 on Saturday after my 14 LED FX-Ion packed up (again) before i'd even got off the ladder down Garlands.

:cuss:

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Out with underground last night - following his incident in Giants - he took the lamp back to Hitch and Hike and Shaun had a fiddle (with his lamp) and got it working agian. Went out last night - then lamp was flickering in the car, then before we'd even got in the bloody cave it had gone out again.

Speleotechnics nice ideas - but absolute shite quality.

Not that tough though

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I dont think it looks too bad considering its been hit by a rock that had 40m to reach full velocity :fart:

I was a bit pissed off at having to buy a new one though, still, at least it wasn't me head.