Using rechargeable batteries in a backup light?

[fmerkel]

I've read a lot of you postings on LED's, lights and batteries. I'd say you have a better grasp of this technology than the GUE administration probably does.

FWIW the UTD (Unified Team Diving-kind of a DIR/GUE organization) group is selling Ultrafire batteries on their website.
UTD X15 LiIon Battery Kit

I have one of those batteries I got with a cheap Chinese light. Claims to be 3000mA > it's 600 (tested). The 4400mA battery they have for their 35W LED canister light is a Tenergy pack. I've opened it up, I know. They want like $150. You can get it for under $50. It is a pretty ordinary 18650 pack. They use really lousy spade connections inside the pack, with crimps. I've had 2 come right off. Lousy workmanship. It's kind of pathetic for a light that is supposed to be that great and that expensive.

These people think they know what they are doing. They don't, or at least some of them don't.

 

[stuartv]

On the other hand, if you are not meticulous and doing advanced dives, then you have bigger problem than your backup light.



Bob

Ha ha! 10-4!

I've read a lot of you postings on LED's, lights and batteries. I'd say you have a better grasp of this technology than the GUE administration probably does.

FWIW the UTD (Unified Team Diving-kind of a DIR/GUE organization) group is selling Ultrafire batteries on their website.
UTD X15 LiIon Battery Kit

I have one of those batteries I got with a cheap Chinese light. Claims to be 3000mA > it's 600 (tested). The 4400mA battery they have for their 35W LED canister light is a Tenergy pack. I've opened it up, I know. They want like $150. You can get it for under $50. It is a pretty ordinary 18650 pack. They use really lousy spade connections inside the pack, with crimps. I've had 2 come right off. Lousy workmanship. It's kind of pathetic for a light that is supposed to be that great and that expensive.

These people think they know what they are doing. They don't, or at least some of them don't.

Thank you and understood!

Do you suppose it's possible that there are "real" Ultrafire batteries that are actually good and then knock-offs that are crap? So, possibly the Ultrafires from UTD are good and the one that came with your cheap Chinese light is just not the same thing? I'm not trying to suggest that that is the case. I know who/what UTD is and I'm certainly not trying to defend them or anything like that. I'm really just more curious how it seems to have come to be that "Ultrafire" is a brand that is marketed as if it's highly desirable yet I never hear anything about Ultrafire except "don't buy them".

 

[stuartv]

I watch my rechargeable batteries and move them from critical uses to non-critical uses, as the batteries loose their charge more quickly, and dispose of them on a regular basis.

As an aside, I'm not sure what you do to monitor or attempt to refresh yours, but I use an Opus BT-C3400 and have gotten really good results with a couple of batteries that had lost quite a bit of capacity by putting them through the Opus' Discharge/Refresh cycle. It brought them back to nearly-new capacity.

 

[fmerkel]

Are there 'real' Ultrafires? Yeah, I suppose. Even a stopped clock is right 2x/day.

I seriously doubt they know what they are doing or they wouldn't even put a product like that on their website. Frankly, it's appalling. They lose a lot of credibility that way.

The Ultrafire I know and love is a re-shrinkwrapper. They get whatever discarded junk they can, put an new shrinkwrap on it, labelled with some kind of outrageous claim and sell it for cheap to people that don't have a clue. It's a really effective sales model apparently.
Take a gander at this, you'll love it:
Disassembly of some UltraFire batteries

(Bookmark that guy, He's GREAT!!!!!)
http://lygte-info.dk/info/batteryDisassemblyUltraFire UK.html
Why even bother when there are known good cells like Panasonic, Sanyo, Samsung, etc?

Stuart, It's time to trust the Force. You are well on your way to knowing what you are doing in this area.

 

[stuartv]

Those UltraFires look awesome! ;-)

And, true. My "good" 18650s are Sanyo. My "good" 26650s are Soshine. Of course, when I say "good" I just mean that they test pretty darn close to their rated capacity. And, in the case of the Sanyos, I've had them for a while and they still seem fine. My Soshine batteries are pretty new.

 

[KeithG]

I never leave any batteries in my lights over night. If they went in a light, I put them in the charger that night. If they've been sitting for more than a couple of weeks, then I charge them all again before I leave to go diving.

You are in good shape. You have a process that positively verifies that your batteries are good before every dive - kind of like checking the pressure in your tank...

Modern Li-ion batteries combined with the proper dive light (one that will not suck your battery dead in a few days) are highly reliable. This is a much better option than hoping that your 6 month old (or year old?) non-rechargeable batteries will still last a dive. Hope is never a good plan.

Removing your batteries overnight is a little paranoid. My 18650 based dive lights can sit on the shelf for 6 months and the batteries still have a full enough charge that my charger signals they are good to go. BUT: I also had an elcheapo dive light that when turned off will suck a 18650 dead in about a week. That light is now landfill.

Modern times require modern solutions.

 

[stuartv]

Removing your batteries overnight is a little paranoid.

I don't do it because I'm worried that something bad will happen. It's just my process for ensuring that they get charged after I use them.

What I said before was actually not 100% correct. If I'm diving two or more days in a row and I take a light in the water on Day 1 and I never turn it on, then I will just leave the battery in there and use it again the next day without attempting to charge it again.

 

[fmerkel]

My routine is to use my lights, yank the batteries, and let them sit until the next dive. I charge them the night before.
If it's NiMh, I may charge them up, then top them off again if they've sat for awhile.
Li-on don't take well to being fully charged and left that way for LONG TERM life. That causes the internal resistance to go up. Better kept at ~50% charge. 30-90% is OK for short term storage.
I'm sure you already know about over charge and discharge problems.

Note - the LDS AA in my strobes may sit inside for 2-4 dives depending on how hard I've used them on any given dive.

 

[stuartv]

I like your process better than mine. I know it's not ideal to let them sit with a full charge. I haven't been doing it your way for the dumbest reason: Right now I only have one container to store my batteries. So I don't want to put them back in there until they are charged. I just need to get myself another container and mark them, to keep charged and uncharged batteries separated. One of those "little things" I keep failing to get around to...

 

[KeithG]

My routine is to use my lights, yank the batteries, and let them sit until the next dive. I charge them the night before.
If it's NiMh, I may charge them up, then top them off again if they've sat for awhile.
Li-on don't take well to being fully charged and left that way for LONG TERM life. That causes the internal resistance to go up. Better kept at ~50% charge. 30-90% is OK for short term storage.
I'm sure you already know about over charge and discharge problems.

Note - the LDS AA in my strobes may sit inside for 2-4 dives depending on how hard I've used them on any given dive.

How long is long term life?

My current set of 8 18650 batteries were scavenged from a discarded laptop battery pack. My laptop was down to about 1 1/2 hours of charge instead of 4+ hours. So I splurged $50 to get a new battery pack for my computer. Curiosity caused me to rip the old pack apart. I found 8 CGR18650CG batteries welded in place. I assumed these were raw unprotected batteries so ran 2 of them through a dozen overcharge / discharge cycles. No apparent effects. Maybe my charger is smart enough to not over charge? Maybe my dive light is smart enough to not over discharge?

Still have them over a year later.