Battery Options

[johnboy]

Hi guys, I'm new to the forum and I'm looking to take on a homebuild. I have most of the internal components required are Lithium ion batteries okay to use in dive torches?
I have tried searching the forum but there seemed to be a system problem.

 

[jspeybro]

some will say you're playing with fire and point you to some explosive experiments, others will tell you that they've been using them for some time without any problem.
I asked a similar question once and didn't get any real answer. I'd like to know for example what happens if you throw a LiIon like the ones from dealextreme in a bucket of seawater. It will probably die or something but if it will go like in the scary youtube movies, I doubt it.

if you want to be sure and go for the safe way, use LiFePO4 batteries. These have a lower capacity but are safe to use and can be charged quite fast from what I read about them. Tillytec is using these.

Johan

 

[gcbryan]

I've had a light flood in saltwater when I was using li-ion rechargeables and nothing happened...the battery is still working today.

I have no other experience other than that one time with li-ions and flooding however.

 

[johnboy]

if you want to be sure and go for the safe way, use LiFePO4 batteries. These have a lower capacity but are safe to use and can be charged quite fast from what I read about them. Tillytec is using these.

Johan

Thats interesting it was the statement on the Greenforce web site stating they don't and wouldn't be using them prompted the question.
I have a few 5.2ah packs to play with that came out of an HID torch so I would be keen to use these to keep costs under control until I have things sorted out.
Thanks for taking the time to reply guys.

 

[Delphinus]

I've had a light flood in saltwater when I was using li-ion rechargeables and nothing happened...the battery is still working today.

I have no other experience other than that one time with li-ions and flooding however.

I have an old Oceanic dive computer that flood with salt water the battery compartment, everything inside melt, it still works but I had to replace the housing.

I'm not an expert but I believe that all Li based batteries are dangerous but I will use them and assume that risk making sure that lamps won't flood, short circuit or overheat

I read in this forum posts were the batteries are drain over they're capacity and lamps overheating, for those Li it's not safe.

 

[Klem]

Lithium Ions are fine for underwater use.

I have had several Li-ion torches flood over the last few years and the most exciting thing that happens is...the torch goes out!

Then later when you open it the ingressed sea water looks a dirty brown colour with a slight smell to it. Salt water does all the usual damage to the internals and so you salvage what you can and move on.

 

[gcbryan]

If you have a flood with an led based light as opposed to HID you have a much better chance of saving the dive light itself.

Leds are sealed pretty well and can function when flooded. The circuits (drivers) don't like it obviously but with today's higher current lights the circuits themselves that are able to handle these increased currents are hardy enough to survive flooding in most cases (unlike lower current circuits like cell phones).

In many cases, you just clean the light with fresh water, dry throughly, and scrub the driver board and it all works again.

Whether the battery fails or not depends on the battery, how sealed it is and how long it was flooded.

Any battery will eat away at plastic if the acid is allowed to come out (alkaline more so than many other types). No one replying to this post has mentioned any personal cases of lithium batteries exploding which is the supposed concern.

 

[SmokedCPU]

i was suspicious before testing...

i charged 3 lipoly cells (baddest of family) and put them in a bucket in the garden over night.
was running fine even tought.

didnt added salt to water :shakehead

 

[Delphinus]

i was suspicious before testing...

i charged 3 lipoly cells (baddest of family) and put them in a bucket in the garden over night.
was running fine even tought.

didnt added salt to water :shakehead

Now if you want to see fire works, punch the battery with a nail and see the result!

Nothing happen with the water because they are sealead, the problem is when the seal broke.

 

[jspeybro]

can the seal break due to the water pressure when at 4 atmosphere pressure? any info on how they are sealed or to what standards they comply?

 

[Delphinus]

can the seal break due to the water pressure when at 4 atmosphere pressure? any info on how they are sealed or to what standards they comply?

I have no idea but if they are full charged a curt circuit could make them swell and break it.

Check this.

http://www.youtube.com/watch?v=W0tE_ohirhI

 

[SmokedCPU]

can the seal break due to the water pressure when at 4 atmosphere pressure? any info on how they are sealed or to what standards they comply?

cells are made to be used by regular humans :twothumbs

If cells are made completely without any air space, then it is almost incompressible, but, in doubt, why not use them as it should, in a canister.

If you are nuts a bit, get a friend who can set truck tire on ring, and place cells in tire, install tire, and inflate tire to 80psi as told on labels .... you'll know what happen soon or

Why spending energy and time for guessing about such sad things Instead build a good canister, or buy one. There are some pretty nice made here...

in worst case, have yourself a pressure pot, and test things... fill the pot with water, then add air pressure....
D*mn you make me remember that i know somebody who's high pressure welder .... i'll get mine some day !! lovecpf I could test some crazy stuff in such thing !

 

[Klem]

Unlikely anyone would be foolish enough to open their torch up underwater, pull out the batteries, and poke nails into them...!

For normal use, and in the event of flooding, your Li-ion's will be fine.

 

[SUBjohan]

didnt added salt to water :shakehead

Thats a pitty
Sweet water has a high resistance and therefore there will be no problem at all. Salt water has a verry low resistance and is therefore much harder on the battery.

Don't forget to remove the protection circuit, high pressure water will bypass this circuit.

Greetz Johan

I think i am going to test this myself soon

Edit: I just performed the tests results will be up soon

 

[SUBjohan]

I think i am going to test this myself soon

Edit: I just performed the tests results will be up soon

So I have done the tests, samples:

- 14650 Trustfire Li-Ion
- 17670 Ultrafire Li-Ion
- 18650 Sony Li-MN

I have the movies on my website: JohanAddink.com I am sorry all text is in Dutch but the movies speak for itself.

After 24 hours in salt water these are the results:
No fire
No extreme venting
Only small bubbles
All the cells are dead
Its messy
No extreme heat of the cells

I think they are save for my divelights

Greetz Johan

 

[350xfire]

So I have done the tests, samples:

- 14650 Trustfire Li-Ion
- 17670 Ultrafire Li-Ion
- 18650 Sony Li-MN

I have the movies on my website: JohanAddink.com I am sorry all text is in Dutch but the movies speak for itself.

After 24 hours in salt water these are the results:
No fire
No extreme venting
Only small bubbles
All the cells are dead
Its messy
No extreme heat of the cells

I think they are save for my divelights

Greetz Johan

What would be interesting is to take 8 cells in a totally enclosed canister, fill with salt water and seal the thing up... I bet the bubbles will make enough pressure to cause something to happen...

 

[SUBjohan]

What would be interesting is to take 8 cells in a totally enclosed canister, fill with salt water and seal the thing up... I bet the bubbles will make enough pressure to cause something to happen...

True, but I think this is not the reality. If water can come in air/gas/bubbles can go out.

But if in some strange case the exit for gasses get blocked again, the gasses will escape through the cable (and rupture the cable) before my canister explodes.

Greetz Johan

 

[johnboy]

Thanks guys, will let you know how I get on.

John.

 

[plazma]

All LiIon accidents I have seen have happened during charging. It's a good idea to have a charging bag or box.

I'm looking into using LiMn cells in my divelights. It's safer with the cost of lower capacity. The charge/discharge current is much higher.