28 replies to this topic

[craig]

Certainly you can't deny that explosions have occurred involving Salvo LiIon packs if you read that thread. I read every posting and it doesn't change that basic point. Further, there seem to be plenty there that understand the basic issue that LiIon is much more risky in the event of failure (especially around water) than other battery chemistries. It makes curious what research you did. I'd still like to know what you meant by "Li-ion should react no more violently than NiMh if exposed to salt water if done right." It is not a matter of rapid energy release due to shorting, LiIon batteries can literally explode like dynamite. I have seen videos of small batteries blowing the ICs off of circuit boards and totally destroying an entire computer chassis. NiMH cannot do that.

BTW, I would never do business with anyone who relied on Barry's work and I would NEVER put a large LiIon battery in anything Barry made. I have personal experience with Barry's work, he made some canisters for me that I quickly threw away due to their inadequate engineering, and would never risk my life on any of it. I could say worse.

[Drew]

Limeyx
I think what Craig is saying about your statement that Li-Ion was as safe as NiMH once exposed to water or heat is pretty invalid. Obviously it's not as safe based on chemistry alone. I could've made a larger statement regarding this but I always hope that people do their own research rather than take the word of one guy on the internet, especially manufacturers.
With manufacturing, the unfortunate reality is that 100% safe is not possible. Too many components= too many variables to control. Dive battery packs are even more at risk due to the possibility of full immersion in water.
Better battery pack design would include, sealing off the battery packs to prevent full water immersion. Of course, that means more maintenance requirements.
Basically, I put this info here as a very simple guideline. Always research the product you are going to buy. It helps to know how to use google and also sift out the internet garbage.
Quite a few people complain to me that the information lacks full on recommendations and product endorsements. Well I don't advertise for people and certainly wouldn't do endorsements. More importantly, there are so many variables that I can't anticipate. Look at the FAA, it took them how long to realize that lithium ion battery packs could go bang?
As always, CAVEAT EMPTOR (buyer beware!).

[limeyx]

Limeyx
I think what Craig is saying about your statement that Li-Ion was as safe as NiMH once exposed to water or heat is pretty valid. Obviously it's not as safe based on chemistry alone. I could've made a larger statement regarding this but I always hope that people do their own research rather than take the word of one guy on the internet, especially manufacturers.
With manufacturer, the unfortunate reality is that 100% safe is not possible. Too many components= too many variables to control. Dive battery packs are even more at risk due to the possibility of full immersion in water.
Better battery pack design would include, sealing off the battery packs to prevent full water immersion. Of course, that means more maintenance requirements.
Basically, I put this info here as a very simple guideline. Always research the product you are going to buy. It helps to know how to use google and also sift out the internet garbage.
Look at the FAA, it took them how long to realize that lithium ion battery packs could go bang?
As always, CAVEAT EMPTOR (buyer beware!).

Well, like I said, I am not an expert, but I have been using Li-ion for a couple of years now, and I have been very happy with it. I've flooded a couple of NiMh batteries and blown the lid off my canister, coupled with the fact that all but one of my NiMh batteries eventually failed (although in fairness I dropped a Li-ion in a small puddle and that stopped working some while after)

Of course one should take what a manufacturer says with a pinch of salt. Also, certain people (including people on the thread linked to) seem to have a grudge against certain manufacturers (of course, being a dealer for a rather bitter competitor may have something to do with that)

and regarding home-built stuff -- I really dont have the time for it. I'd far rather have someone else make me a pack and sell me a charger, but thats maybe because I am not that handy.

There are far bigger Li-ion batteries than my lil old 15Ah hr batteries in use u/w

[Drew]

Well, like I said, I am not an expert, but I have been using Li-ion for a couple of years now, and I have been very happy with it. I've flooded a couple of NiMh batteries and blown the lid off my canister, coupled with the fact that all but one of my NiMh batteries eventually failed (although in fairness I dropped a Li-ion in a small puddle and that stopped working some while after.

There are far bigger Li-ion batteries than my lil old 15Ah hr batteries in use u/w

What Craig is saying is that the Li-Ion could possible do a lot more than just stop working when flooded. It can ignite and start a nasty reaction which could end in explosion. The bigger the pack, the larger the explosion.
Obviously we all take risks but WP's intention is to inform people about everything underwater camera related.

[limeyx]

The bigger the pack, the larger the explosion.
Obviously we all take risks but WP's intention is to inform people about everything underwater camera related.

I agree (well, maybe WP doesn't intend to inform people about *everything*). However, posting a link to a thread where the "explosion" may very well have happened independently of the battery technology may not be "accurate" informing.

I think this discussion has for now run its useful end ...

[craig]

However, posting a link to a thread where the "explosion" may very well have happened independently of the battery technology may not be "accurate" informing.

Except that's not true. NiMH batteries won't "explode" in the same sense that LiIon batteries can. Besides, the link simply shows that the maker of your light has had products explode. Note that not one but four separate Salvo incidents are referenced in addition to one reference to a LiIon explosion and you might read TobinGeorge's post on page 2. Not everyone has the knowledge and skill to understand how to make such products sufficiently safe and I'm too skeptical to take the word of a manufacturer in fire-fighting mode. It's not just LiIon that's the point here either. Huge energy storage, violent battery chemistries, lethal ballast voltages, and soft plastic enclosures with cheesy clips don't mix in my opinion.

There have recently been incidents of notebook batteries catching fire and exploding. You would think, considering the volumes in that market, that engineers would put careful thought into preventing that. It shows you the difference between LiIon and NiMH in terms of potential for catastrophic failure.

I have a bias against large LiIon batteries and I have tried to explain my reasoning. It's not important to me to change your mind. Further, I am not advocating anyone undertake a DIY project, I was simply showing what I achieved (quite a while ago) in contrast to your claim that LiIon offers much greater power in the same size package. I believe 100Wh in 3.5 pounds is pretty good achievement and it doesn't involve nearly the injury risk or any full-custom charger solution. LiIon can do better but not with off-the-shelf cells that are designed small enough to be safe in the absence of custom safety engineering.

I would still like to know the Wh ratings of those LiIon packs. Ah is not a rating of power. Airlines have restrictions on both Lithium content AND overall power and 100Wh is the largest allowed without permit. Looking at Salvo's current site, it appears they are offering packs in the 250Wh total capacity range. If those are a single pack, then technically they are hazardous cargo and you can't just stick them in your checked bags (legally).

What Craig is saying is that the Li-Ion could possible do a lot more than just stop working when flooded. It can ignite and start a nasty reaction which could end in explosion. The bigger the pack, the larger the explosion.

I was advised by my engineer whose career was LiIon batteries, charging circuits and power supplies, that my target battery size in LiIon (similar to Salvo's large packs BTW) if exposed to a total flood could very well blow me into pieces underwater. So, yes, that's what I'm trying to say! Just because an anecdotal flood doesn't result in explosion doesn't mean it can't happen.

[Drew]

Airlines have restrictions on both Lithium content AND overall power and 100Wh is the largest allowed without permit. Looking at Salvo's current site, it appears they are offering packs in the 250Wh total capacity range. If those are a single pack, then technically they are hazardous cargo and you can't just stick them in your checked bags (legally).

Thanks for reminding me, Craig. I'd forgotten to update for Li-Ion battery limit for US travellers. FYI, that 100Wh limit is for cargo and not for passenger baggage. Here is the DOT mandate:
http://safetravel.do...uick_chart.html
So basically if you have a Li-Ion battery pack that is up to 300Wh, then you can check it in but you can't have spares. Apparently Lithium Manganese is not affected by these rulings, or at least the DOT haven't tested them yet.

[Drew]

Reupdated for LED lights for CRI yet again. New lights new standards.

[Drew]

Updated for the TLIC. Sorry, I forgot to do so when it was announced in Dec.