Batteries for Dive Lights: Alkaline, NiMH, Lithium Ion, Manganese or Iron Phosphate?

[whitenoise]

Sorry everyone if I keep asking stupid questions but you people know all this stuff and I don't have a clue!

In my search through the various off-the-shelf dive lights that are available, there appears to be a difference of opinion in regards to what the best battery source is. Some dive lights use AA's or C cells, some use NiMh, some Lithium Ions, others Lithium Manganese or Lithium Iron. Which ones would you think would be the best ones to use?

I'm bound to be corrected here (which is good!) but this is my limited understanding, so please excuse any wrong terminology! The NiMh has a good capacity, are cheap but high self-discharge. Now the Li-ion have good power, relatively cheap, low self-discharge and but can be unstable and shouldn't be used in dive torches. The Manganese version is much more stable, very low self-discharge but doesn't hold as much and can be damaged if left with a certain amount of low charge? The LiFe batteries seem the best as they are very stable, good power, don't have the storage issues, have very low self-discharge but are expensive and difficult to find?

What do you people power your LED torches on, have I been sucked in by the marketing hype?

Thanks! =)

 

[Egsise]

Re: Batteries: Alkaline, NiMH, Lithium Ion, Manganese or Iron Phosphate?

My choice is AA NiMH.
Search Sanyo Eneloop, GP ReCyko, ROV Hybrid etc, those are low self discharge NiMH batteries.

 

[DM51]

Re: Batteries: Alkaline, NiMH, Lithium Ion, Manganese or Iron Phosphate?

You'll find Li-Ion (LiCo), NiMH and LiMn in good dive lights, although some manufacturers are wary of LiCo as it has an (unjustifiably) poor reputation for safety.

Weight/size is not an issue with dive lights that have an umbilical lead from the battery canister to the head. Most dive-lights will be chunkier and larger than regular lights anyway, partly due to the obvious need for them to be completely water-tight.

Self-discharge is not really an issue either, as typically a dive-light will be largely or completely discharged during a day's diving, then recharged for the following day. NiMH is therefore a popular choice with some manufacturers.

I mentioned the safety issue with LiCo. If LiCo cells are treated properly, they are just as safe as any other type. There is no reason at all not to use LiCo cells where the cells can be removed and individually recharged, rather than series charged. Some people rely on protection circuits to prevent individual cells from overcharging, but this is unwise - and it will not prevent cells from going out of balance.

LiMn is used in some high-end lights, by such manufacturers as Hartenberger, who make some of the the best dive-lights available. They have models in both NiMH and LiMn. LiMn does not have the high capacity/size ratio as LiCo, but at ~2/3 it is perfectly adequate, and the added robustness of the chemistry makes it a very safe and reliable choice.

Alkaline is not a good choice at all, although many smaller/cheaper back-up lights are made to take the widely-available AA cells. If you buy a light designed for alkaline cells, you will do better to use NiMH cells instead.

 

[jspeybro]

Hi,

regarding the safety of these LiCo batteries, in what situation are they not safe besides puncturing them or throwing them in a fire?
can they withstand a situation where your light is flooded by seawater for example? (I don't care if the battery is dead, but I wouldn't want to have a fireball in my hand while underwater...:thinking I tried searching for this answer, but can't find it. On youtube there are plenty of video's showing the dangers of lithium and water, but those are all damaged batteries. Can I assume that as long as my battery is intact, it wont explode?
Or will the battery 'collapse under the pressure and cause the lithium to be exposed to the water? I don't even know if a battery is hermetically sealed or not...

I read that TillyTec switched to LiFePO4 batteries, probably due to safety and fast recharge times. When I look for such batteries, they seem to have less capacity though. Would that be a problem for example when using them to power a high power led (cree Q5 or something like that)?

 

[DM51]

regarding the safety of these LiCo batteries, in what situation are they not safe besides puncturing them or throwing them in a fire?

Most problems are caused when they are over-discharged and then recharged incorrectly. In such circumstances they can vent with flame (blow), although given their ubiquity in modern electronics this is surprisingly rare.

can they withstand a situation where your light is flooded by seawater for example?

With a protected LiCo cell, the protection circuit may operate to cut off the current, but I personally wouldn't bank on the cell's insulation being able to prevent seawater from bypassing the circuit. No battery will withstand being directly immersed in seawater, which is a good electrical conductor. In every case there will be a dead short, causing a total and rapid discharge of the cell. That is not to say that it will turn into an underwater bomb and blow your hand off – that won't happen. The worst you are likely to notice would be some gas bubbles coming out of the light.

 

[alpg88]

i,d go with li ion, my laptop uses them, cell phone..ect none blew up, or cought on fire.
while li ion expencive ones they do offer high capacity-longer runtime.
if god forbid your light starts takin on water, shorted batterys would be the least of your consearn, salt water would kill you circits, so if it starts filling with water, might as well let it go and wave good bye to it.

 

[whitenoise]

Re: Batteries in Dive Lights: Alk, NiMH, Lithium Ion, Manganese or Iron Phosphate?

Thanks everyone for their advice! I did look at the low self-discharge batteries like Eneloop and ReCyko, but these seem to be only in AA or AAA size? Don't they make these type of batteries in sizes like C?

DM51 you seem confident about the safety of LiCo, so is the whole perception that its unsafe especially for a dive light is just scare tactics? There appear to be few dive light manufacturers who use these, as while they might not explode in your hand, they probably don't want to take that risk!

I've seen the models by Hartenberger and they do look good, is that a general consensus that their torches are well made? The LiMN does have the advantages of the more stable chemistry as you mentioned, but I've read that it has problems with storage? Something about it has to be stored with a certain % left in the cell otherwise it can cause permanent damage? Wouldn't want to buy an expensive light using these cells if this was the case!

I've also noticed like you jspeybro, that TillyTec are now selling all their torches with only LiFePO4 (Lithium Iron Phosphate) batteries, which according to them, is the best battery chemistry out. They claim that these 'new' cells don't have the unstable issues like LiCo, but also don't have storage issues of LiMn. While they do apparently offer less capacity than LiCo, they can also be fully charged in about an hour, with no worries about deep discharge or usage in cold/warm temps. It seems odd they are the only people to use these types of batteries, do you think that's for a reason? Greenforce still seem to be using NiMh which seems almost two 'generations' older than LiFePO4?

 

[DM51]

Re: Batteries in Dive Lights: Alk, NiMH, Lithium Ion, Manganese or Iron Phosphate?

If you think about it, a dive light is essentially no different from any other light except for its enhanced ability to remain water-tight. There's no reason why Li-Ion (LiCo) batteries should not be used. Nothing is going to happen to the cells during use unless the light floods, in which case the entire unit will most likely be a write-off (certainly the cells will be, whatever chemistry they are).

As to Hartenberger, I have 2 of them: a Maxi Compact LCD, and a Nano Compact. Both are superb quality units. Both use LiMn cells, which should be stored with ~60% capacity. That's not difficult - fully charge them and then run the light (in a bath of water) for 40% of the stated run-time. Then you can store them for months and no damage or degradation will occur.

 

[H20doctor]

i only use 18650 ultra-fires in my lights to power them.. Li-ion

 

[whitenoise]

Thanks to all once again!

 

[Barbarin]

After thousands of lights being sold, near 90% of them using Li-ION 18650 batteries, we just know off one incident, and it was in our own factory while testing a poor quality battery with a poor quality charger.

Some of our lights are certified and used for firefighting, and have undergone very demanding and stressing test including temperature shocks.

You can feel safe to use Li-ION, in case of good Li-IONs, good chargers and good lights from serious companies.

Regards,

Javier

 

[jspeybro]

the dealextremes, are they any good? or are that such poor quality batteries you are talking about...
any suggestions where to get these batteries?

Johan

 

[whitenoise]

The more and more posts I read on CPF Javier, the more the concenus seems to be that what you have said is true. But if protected Li-Ions used in a safe way are ok, why is Li-Mn and Li-Fe seemingly "the done thing" - do you think it is just marketing hype?

 

[Linger]

whitenoise,
If you're looking for a dive light, you are in luck. There are a few people here who can build you one that is years ahead of what you'd find in most dive shops. As you learn more you will realize that most manufacturors use components and tech that is almost half a decade old, and market it as new innovations for 2010.
For batteries, it's important that you have ones that you can use when you need to. If you're travelling a lot, AA nihms may be great, you might feel its only a matter of time before your customs officers take issue with lithium batteries.
Or you may find that nothing gives your the power and versatility of lithium, and that nothing else will keep up with the way you want to use them. Just fyi lithium are usually an internet sourced thing and you'd have to wait for replacements to be shipped as they won't be available locally (no matter where 'local' is...I can't buy them in my city and its an urban center in a G8 country...)

 

[whitenoise]

Excellent thoughts there linger! :twothumbs I'm still new here, but I've been catching up on all the past discussions here in the dive light forum. You are absolutely right, the more I read the more I think wow! the people who make these dive lights are seriously talented and the lights themselves are awesome! :bow: :bow:

To think only a short time ago I was looking at the big name manufacturers for my next dive light, and prices weren't cheap for not much light! I look here and some of the lights blow me away - I'm so glad that I didn't get my wallet out for those off-the-shelf lights!!! I still reading here, but soon I'll know enough to hopefully get someone to build a light for me Some of the ones mentioned already look good!

I see what you say about the lithium batteries. Surely though if you put the torch in your hand luggage, or even take the batteries out, a couple of batteries aren't going to cause any problems? They allow laptops and mobiles and the like so batteries are small fry in comparision?

Where do you usually get your Li-ions from? I think I've read something here about protected li-lions, possibly ultrafire, or surefire (something like that) but can't remember where from.

 

[Barbarin]

The more and more posts I read on CPF Javier, the more the concenus seems to be that what you have said is true. But if protected Li-Ions used in a safe way are ok, why is Li-Mn and Li-Fe seemingly "the done thing" - do you think it is just marketing hype?

If you look here on CPF you will find many incidents with low quality Li's (including LiMno2), and I can tell you about many with SLA's, NiMH's, NiCd... I think there is not absolutely safe battery chemistry. Basically, a battery holds an important amount of energy that can be delivered in case of failure. Gasoline is the same, but need oxygen.. Batteries is some way are like explosives.

Well, more important that the chemistry is the manufacturer of the battery and of course the control of the charge and discharge. An even thought, you must keep in mind that even taking care of everything, there could be failures (In that case you must be carefull with gas build up, how do caps open (twist is safer than latches....) and in case an importat number of batteries is being used, pressure release systems (a ver simple screw, for example).

Regards,

Javier

 

[whitenoise]

Thanks for that Javier, thats great