Backup light batteries

[OneBrightGator]

My advise is to use alkalines and replace them every two years, need it or not or to use NiMH batteries and charge them right up to the moment you're about to go into the water. As to burn testing or leaving them on, switch them on and off and leave it at that ... that's why you carry two backups.

So you'd trust 23 month old alkalines that you've never actually used over NiMH rechargeables with a history of good burn times that have just been topped off?

 

[OneBrightGator]

LED or halogen bulb failures? Or do you mean flooding from turning them on?

The whole rechargable biz seems like an awfully convoluted way to avoid cheap alkalines. Just measure your voltage (1.5V per cell) before diving and go for it. Swap them out every couple years into a garage flashlight at home or after using a light. Simple, reliable, no recharging to deal with.

You'd have to have a really unreliable primary light to even start to make back the cost differences from the occasional replacement of alkalines. So what's the benefit of the rechargables?

Halogen failures from the initial jolt of power and failures such as unscrewing the bezel, water intrusion through a dirty or twisted o-ring, water intrusion when the bezel is not making good enough contact with the o-rings, etc. I've had quite a few backup lights come up flooded after not even touching them during the dive, good thing I didn't need them!

I'm not trying save money, I'm looking for something better. I've already listed some of the benefits I see, I think using the correct rechargeables is as safe or safer then alkalines.

 

[OneBrightGator]

Doesn't leaving them on during the dive defeat the purpose of a "backup?" If it's supposed to carry enough burn time to allow you to complete the dive, does it make sense to go on a 4-hr dive with a 4-hr burn time light...and turn it on so that if you're lucky you'll get exactly 4 hours of burn from it?

It doesn't make sense to go on a 4-hr dive with a 4-hr burn time light regardless of the batteries or whether it's on or off. That's just poor dive planning, you never plan a dive time equal to the burn time on your lights, backup or otherwise.

 

[OneBrightGator]

I wouldn´t turn on the backups until you need them for obvious reasons...

I think the "old reasons" against rechargeables aren´t valid anymore. One of my backups is currently serving as a bicycle-light as well and I´ve been toying with the idea of going rechargeable for it but...regular ones are so cheap that it still doesen´t make sense to go rechargeable...All my backups are LED so that may have something to do with my attitude...

My regular buddy has a LED as a primary that can be used with regular rechargeables and he´s been using it with those for well over a year without any issues so the only con of them is cost/hassle, IMO...

Like I said, I'm not looking for a cost savings, the increased cost of the batteries plus the charger will probably make it slightly more expensive, not less.

 

[OneBrightGator]

I use a lot of rechargeable NiMH batteries in my underwater camera-flash. Yes, the NiMH batteries are an improvement over the older rechargeable batteries. You might say my camera goes through NiMH batteries like **** through a goose.

My experience with NiMH does not inspire me to switch from alkaline to rechargeable NiMH for my backup lights. When I need a backup light I want it to work. I do NOT have that kind of confidence in rechargeable NiMH batteries.

In fact, I have thrown away all of my NiMH batteries. I switched to rechargeable lithium batteries for my camera and alkaline batteries for my flash.

I can understand your logic, but is it really a fair comparison? High drain devices such as digital cameras and flashes compared to a low drain device such as a LED backup light? I imagine that NiMH is the most widely used cannister light battery right now. Perhaps Li-Ion batteries would be even better in backup lights?

 

[OneBrightGator]

I wouldn't want to be the guy behind you.

I don't want you to be the guy behind me.

 

[Thalassamania]

So you'd trust 23 month old alkalines that you've never actually used over NiMH rechargeables with a history of good burn times that have just been topped off?

Carrying two backup lights I'd be perfectly happy with either solution, but the 23 month old alkaline would be a damn sight less trouble. Hasn't anyone built an LED enunciating, voltage detect circuit into a light? It's no big deal and you could flip on the light, look for the green LED and know that you're voltage was where it should be.

 

[rjack321]

I just check the voltage at the beginning of each dive day. And yes some 1.5+V alkalines might be 24ish months old. I trust them just fine.

I have had one backup flood (halycyon mini-scout) due to gunk in the Oring. That's my only backup light failure.

 

[Thalassamania]

The point is that every time you open and close a light you run a risk of flooding it when it goes in the water. If I'm going to open it and check the voltage for every dive, I'd start giving thought to NIMH. What I really want is a backup light that shows me that the voltage is good with an LED when I flip it on so that I don't have to open it to check the batteries. I's a rather simple circuit (you can buy a 12 volt one for your car for ten bucks).

 

[wjknobles]

as long as you maintain your gear properly you shouldn't have a problem ... if you have a history of having the lights fail due to flooding, perhaps you should clean/ check/ replace the o-rings on the light more often ... cheap fix to the problem

as for using rechargables, the cost of good disposables is so low that it is not worth the hassle of dealing with having to charge batteries for your back-up. put good batteries in your back-ups, check them before dives, and replace them after use ... even if you have some insane amount of burn time due to LED's ... better safe than without light.