Q about backup lights

[battles2a5]

So I'm entertaining the idea of doing DIR-F then following the GUE route for cave training. Haven't decided yet, but the option is open. My rig is pretty-much DIR compliant. The only question I have is around my back-up lights. I have 2 dive rite "tec" back-ups. They use 4 "AA" batteries instead of 3 "C" cells. Everything else about the light is comliant; non-rechargeable, no switches, turns on/off by rotating the bezel, etc. Is this going to be an issue in DIR-F? I can't imagine that it would be an issue but you never know. Thanks for the advice.

Thanks,
Ryan

 

[Bismark]

Best bet is to email your future GUE F instructor and ask him or her. All the other advice you get here on SB is second hand. Go straight to the source.

 

[Sloth]

All of my lights are the taboo Salvo lights. One was the rat jr with the little CR-123 batteries. The instructor never batted an eye at it. You should be ok.

 

[pengwe]

slight hijack - what's the issue with rechargeable batteries?

 

[Jason B]

So I'm entertaining the idea of doing DIR-F then following the GUE route for cave training.

Hey Ryan. I think the idea you are entertaining is a good one. Glad to hear you are at least giving it thought. You should try and get over our way one weekend for some diving with us. We'd love to have you come join us and see how we do things.

 

[jjones9527]

slight hijack - what's the issue with rechargeable batteries?

NiCads don't have the same voltage per cell as Alkaline, and develop a memory effect, drastically reducing the max capacity and burn time. As well rather than gradually fading out, they will fade much quicker. Its common practice that once you use a back up light, the batteries are changed (as well as being done when the clocks change). By using rechargeables, you could end up with cells that are beyond their life cycle. I guess you could mitigate this by using newer technology rechargeables, and regularly burn testing and cycling them, but why bother for a couple bucks in batteries a year.

 

[Doc Intrepid]

Ryan,

Your fundies instructor doesn't care about your lights. Fundies isn't about lights. Take the course without them, as far as that is concerned. OTOH, you may wish to discuss them with your instructor vis a vis follow-on training....but I'd also discuss them with your cave instructor before you put any money into replacements.

FWIW. YMMV.

 

[deepstops]

slight hijack - what's the issue with rechargeable batteries?

NiCads and NiMH batteries tend to lose some percentage of their charge every day (there are some new NiMHs that don't) but the purpose of your back-up light(s) is/are to be there when needed. Using rechargeable batteries in your back-up isn't a good idea since they may work when you test them and die shortly afterward. And as already pointed out, when they die, they fast rather than gradually. Additionally, most back-ups like the Scout are driving a 6vdc bulb with 4.5vdc (under-driven) to increase the filament's reliability. Using rechargeable batteries would further drop the voltage to 3.6vdc.

All that being said and getting back to the OP's question, I've know some folks that did DIR-F using Tec 40s as their back-up light.

 

[rainman_02]

Additionally, most back-ups like the Scout are driving a 6vdc bulb with 4.5vdc (under-driven) to increase the filament's reliability. Using rechargeable batteries would further drop the voltage to 3.6vdc.

I thought the SL4 bulb was a 4.5V that UK was over-driving to 6V? That way the Scout light was providing the correct amount of voltage so as to not sacrifice reliability/burn time for brightness...

But I've been known to be wrong before.

 

[pengwe]

I see. Thanks for the answers.