AA rechargeable batteries

[Greg Jensen]

My rechargeable strobe batteries were taking longer and loooonnngger to power up my strobe after a shot, so I finally bought some of these:



since they seemed pretty good. For reasons that are still unclear, the masochist in me read the fine print of warnings, etc. that came with them, including this gem: "Do not use batteries to power underwater devices".

Any idea why it would say this? I mean, WTF? (What's This For?)

[Scubie Doo]

I think it's a simple CYA. They don't want someone trying to get a refund cause they got wet and don't work anymore. That's my thought.

[fmerkel]

Because there area a certain class of people and attendant layers that are the bane of our existence. I'd not be surprised it the instructions indicate not to eat them.

When put in saltwater in an electronic device, and the device leaks the battery shorts and starts electrolysis-amperage dump. The higher the battery performance, the more vigorous the electrolysis, generally eating up the contacts and creating all kind of ugly mess.
Alkaline batteries are nasty, NiMh are scary, Lithium can be downright amazing to the point of exploding the devices. My wife got a small leak she didn't realize in a UK 400R (NiMh D-cells). Back on the dive boat for awhile they heard a POP and the light head blew off across the deck.

[Scubie Doo]

That's interesting. Ikelite recently upgraded my battery packs to the new Lithium packs. They use to be the NiMh packs. If there was an explosion issue (not saying there isn't). Why would Ikelite use these potentially dangerous batteries in there strobes? I know performance is better, but few manufacturers choose performance over potential danger and lawsuits.

Just curious.

[dlh]

Every camera, phone, and laptop in the world has Lithium Ion batteries. They are as safe as anything else in general use.

As for rechargeable AA batteries, the Sanyo Eneloop brand is considered by lot of folks to be the best. They will retain a full charge for over a year, and last for 1000+ of recharge cycles. Most of the traditional rechargeables will pretty rapidly discharge when left idle, in just a number of weeks.

[Greg Jensen]

[quote="fmerkel"]Because there area a certain class of people and attendant layers that are the bane of our existence. I'd not be surprised it the instructions indicate not to eat them.

Well, not exactly, but it does say to call a doctor if you swallow them. I figured you would just eat a box of baking soda

From what I could find out, these ARE the Sanyo batteries, just in a different wrapper.

Thanks for the replies!

[fmerkel]

The real problem is eating up your electronics, but all the batteries do that, it's just a matter of speed and degree. The 'danger' is loosely related to capacity to dump amperage, which is the same thing as better performance. When they short they start to dump amperage....fast. When they do this they off-gas. Under normal use re-chargeable batteries are completely sealed with no off-gassing. They do have over pressure vents to prevent explosions in case of issues, over charge being a big one in lithium batteries. Stuff them in a sealed compartment and this safety measure is thwarted to some extent. Consumer electronics with lithium batteries have sophisticated electronic circuits to keep the charge and discharge in a tight range, which is critical for lithium. THESE CIRCUITS ARE WHAT KEEP THEM SAFE, NOT THE INHERENT LITHIUM CHEMISTRY.
But for LED lights and other similar 'cheap Chinese' electronics you can get and use either protected (with a limiting circuit) or unprotected batteries. Some of the better lights have this built in. If you buy from a mainstream source chances are this kind of protection is part of the package.

(Important note on 18650 lithium ion batteries - Don't buy ANY 18650 that is really cheap, especially if it called Ultrafire or (anything)fire. They are almost all complete crap. Really cheap lithium charges are generally pretty suspect also. Purchase and use at your own risk)

Underwater on a small battery pack any explosion is going to be pretty small and absorbed by the water. What's a strobe going to do really-blow the little cover off and go 3 inches? POP, might be a better expression. It's kind of a moot point since the flood alone is going to hose things up and flooding is generally considered an operator failure.

Note on Eneloop batteries, now Panasonic. The Eneloops all used to come from Japan. After being swallowed by Panasonic some now come from China. They are still good, just not as good. Some of the knock-offs (Amazon and a few others) are re-branded Sanyo/Eneloops so are great. Figuring out which ones can be a real challenge. If at all possible you want them to come from Japan, for sure.Imedions are quite good and work great in strobes.

[Jeff Pack]

You have to be very careful buying 18650's. There are 2 true panasonic 3400's. One is made in Japan, other is China(The CHina cell having a greater internal resistance). The problem, is other china plants are taking crap cells, giving them Panasonic labels, say made in Japan, and selling them as Panasonic cells. Ebay is ripe with them,same for Amazon.

I finally have a good source for unprotected 18650's that are the legit pannys and test at their rated capacity, unlike the fake Panasonic labeled cells that tested at 2800mah.

[Tangfish]

I finally have a good source for unprotected 18650's that are the legit pannys and test at their rated capacity, unlike the fake Panasonic labeled cells that tested at 2800mah.

Can you share said source?

[Jeff Pack]

http://www.ebay.com/itm/321688042968?_t ... EBIDX%3AIT

These tested nominal 3200mah at .5a discharge.

The fake ones tested at about 2800 with a worse discharge curve.

Jeff Gerritsen now has a spot welder, he made my pack, and is currently building a Sierra Pack for someone with the 3400's.

As I recall, buying in quantity (60 cells) knocked it to around 8$ a cell.

[fmerkel]

If you don't want tabs, Mountain Electric is a reliable state side source for batteries and chargers. Pretty much all of their stuff has been tested and is supported. http://www.mtnelectronics.com/index.php ... ry&path=59