Expected battery output - Spelotechnics 'Nickel?

[underground]

Since my FX-Ion 14 led light has started seeming a little less bright than it was, I put a multimeter on it to test the Voltage (at least that's what I think i did - set the dial to the '20' position on what I think is the AC voltage section) and it reads 3.85 (this is after a couple of short - i.e. 2 hour - trips). I recall when i last did this with the old li-ion battery it read more around the 10.8 mark (but I don't know if the reading is the one I need, elctronics and physics were never good subjects for me).

Does anyone know that this would be the reason for the dimness on LEDs (I know they can get dimmer as the cell discharges).

Also can anyone suggest any additional uses of the multimeter to give any useful info on the state of the battery?

 

[ianball11]

Have you contacted Speleo people?

 

[underground]

More times than I care to remember. I'd like some impartial info.  :

 

[rhychydwr1]

Also can anyone suggest any additional uses of the multimeter to give any useful info on the state of the battery?

Yes, try DC volts, on the voltage section.

Also check the voltage with the light on and the light off.

 

[SamT]

yep - you want DC, not AC.

other than that, its hard to perform any kind of electronic 'capacity' testing without much geekyness.

 

[underground]

Thanks Tony... I'll try again!

OK, I have the red wire attached to the 10A DC socket on the machine. And the knob turned to the '20' setting in a section labelled 'V' with one solid and one dotted line next to it. I So I think it's on DC although I'm not sure what the solid / dotted lines denote.

An identical machine on the 'net with different labels has the same section labelled DCV. So hopefully I had it right in the first place

So, the 6V battery looks to be giving 3.85V. Would this have any effect on the LED array brightness, then? That's what I wanted to know really. ST have told me to expect a drop in current along with discharge, but i don't know how current and Voltage relate, even...

In fact if anyone knows a good website to teach electronics eejits like myself some fundamentals, I'm all ears.

 

[SamT]

google ohms law.

its the start of it all.

V=IR

 

[Chocolate fireguard]

Also can anyone suggest any additional uses of the multimeter to give any useful info on the state of the battery?

The only reliable test for a battery is to charge it and then discharge it through its normal load (your lamp) measuring the current/time behaviour until it is flat and comparing the calculated capacity in amp*hours with the manufacturer`s figure. This is not easy to set up and anyway life`s too short.
If it were my lamp (and my analogue meter) I would set the meter to the 10 Amp range (if it has one) and momentarily discharge the battery through it. Be sure you find the battery terminals to do this as any electronics caught up in this may not survive! A healthy battery will cause the needle to kick right to the end of the scale. From what you have said so far your battery sounds to be unhealthy. If you do not want to risk this the measurement of voltage on and off load mentioned earlier seems the best bet. I wouldn`t expect a healthy freshly-charged battery to show a difference of more than a fraction of a volt.

 

[ChrisJC]

In fact if anyone knows a good website to teach electronics eejits like myself some fundamentals, I'm all ears.

It took me four years of full time study to become proficient in electronics, so on that basis, I'd recommend you find a friendly local electronics person to look at it for you!

Chris.

 

[underground]

Thanks for the replies everyone - and ChrisJC - thanks, I don't feel so bad now  '

 

[potholer]

If a 14LED unit was seeming dim, I'd wonder first whether that's because you're comparing it to brighter lamps than previously, and second, whether it's at least partly down to the LEDs just getting old and tired. Those 5mm LEDs don't last forever, especially if they're run near their rated current in an unregulated light.

I'd suggest measuring the DC voltage inside the headset when the light is turned on, and when it's turned off. (red lead in normal meter socket, not the 10A one).
If the on-load voltage on a part-discharged (not freshly-charged) battery pack is somewhere in the 3.65V-3.85V range, and the LEDs still look dim at that kind of drive voltage, I'd suspect the LEDs, since somewhere around 3.75V is where a 3xNiMH pack is likely to be for most of its discharge.

 

[underground]

If a 14LED unit was seeming dim, I'd wonder first whether that's because you're comparing it to brighter lamps than previously, and second, whether it's at least partly down to the LEDs just getting old and tired. Those 5mm LEDs don't last forever, especially if they're run near their rated current in an unregulated light.

I'd suggest measuring the DC voltage inside the headset when the light is turned on, and when it's turned off. (red lead in normal meter socket, not the 10A one).
If the on-load voltage on a part-discharged (not freshly-charged) battery pack is somewhere in the 3.65V-3.85V range, and the LEDs still look dim at that kind of drive voltage, I'd suspect the LEDs, since somewhere around 3.75V is where a 3xNiMH pack is likely to be for most of its discharge.

Sorry for the delay in responding - thanks potholer, that was really helpful. The Nickel pack was putting out 3.85v once I tested it correctly this morning as per your suggestion, so I'm guessing issues with the LEDs.

I'm now trying to decide whether to take a huge lap and attempt to build something myself, buy a drop in conversion (Bisun or retro2), or an 14 LED Petzl Duo - which on first impressions seems a nice package etc. but a little flickery when switching, on the one I borrowed to try out.

If anyone has any ideas on a relatively low cost way of putting some posh LEDs inside an Oldham headset (i.e  emitter and driver combinations) that I don't have to buy special batteries and charger to run, I'd be really keen to hear some ideas.

Thanks to all. Sorry for being so clueless on this particular issue 

 

[rsch]

I'm now trying to decide whether to take a huge leap and attempt to build something myself, buy a drop in conversion (Bisun or retro2), or an 14 LED Petzl Duo - which on first impressions seems a nice package etc. but a little flickery when switching, on the one I borrowed to try out.

If anyone has any ideas on a relatively low cost way of putting some posh LEDs inside an Oldham headset (i.e  emitter and driver combinations) that I don't have to buy special batteries and charger to run, I'd be really keen to hear some ideas.

One happy Bisun customer here, unconnected except by commercial transaction. Happy to recommend that as a thoroughly satisfactory option in my experience.

 

[Geoff R]

Were the LED's found to be at fault  :-\

If its any help, my own Spelio 14 x LED lamp started to go slightly faint; a noticeable difference when connected not to its normal Spelio ?nickel-cadmium? battery with its ?green top?  but to a standard non-rechargeable cell pack.

I took absolutely no notice of this minor degrade until one day on an SRT pitch my light suddenly failed ? the battery pack had given up completely after some 4+ years of use.

Solving the problem I chose to split the Spelio pack apart and replace the 3 x  Ni-Cd?s inside with new high-charge capable Nickel-metal hydrides (NiMh). The 3 new batteries were kindly tabbed together by the UK mail order retailer AND heat shrunk packed all ready to drop straight into the old Spelio battery case with a bit of silicon sealant. 

 

[Agrophobic]

Hi. my own experience of spelio "nickel" packs is that the contacts where the cable plugs in corrode, this reduces the current through the leds. if your contacts are green or brown rather than shiny brass then give em a GOOD clean out.
the same goes for the switch contacts inside the head, they go green over time too.
If you want to upgrade but dont know electronics too well, i'd go for the retro2.

 

[underground]

I got a bit fed up of wondering, and fed up of dimness, so for now invested in a Duo. I was worried about spending quite a bit of money and ending up with a bodge job or needing loads of new batteries / chargers.

Happy with the change, particularly weight-wise. I suppose it doesn't have this mega lighting power that a retro2 would have had but it does the job.

 

[mulucaver]

shrunk packed all ready to drop straight into the old Spelio battery case with a bit of silicon sealant. 

A bit of silicone sealant is OK but be careful. I've heard of people totally sealing things in silcone sealant to protect them from water and, apparently it gives off acetic acid while curing thus causing all the bits inside to corrode.

 

[Geoff R]

Thanks     I only used a bit of silicon onto the plastic shrink wrap and around the edges ... and drilled a small hole in advance to let out air as I assembled the two halves together and for silicon drying. It did smell a bit for a couple of weeks; then I sealed the final small drill hole.