A New Bare Bulb Flash Arrives

CheetahStand wrote in post #16302331
Just to make this clear,We do not have plan to make 6000mAh.
If we do, will first let POTN members know.
We have plan for 1200W studio light.one second 10 pops.Diration 1/20000 sec.Can work with CL-Tx/Rx.
Stay tune......

studio light with T1 1/20000 sec duration ! i'm ready to buy. i also want to buy a nice newAir-Gap flash.

with all the nice Arduino based controllers for high speed photography we need some short duration flash.

ZoranC wrote in post #16310467
Edward, who's your buddy?

You will be the first one in USA!!
Just like when we first announce CL-180.You the first one pre-order 3 sets!!!

DukeMorse wrote in post #16307597
BTS shot of me using the Cheetah Light CL-180, 33" collapsable beauty dish, speed pro bracket, battery mount, and cheetah boom...the whole Cheetah set up

Here is what the end result looked like...

HTTP response: 403 | MIME changed to 'text/plain'

I also shot this with that same set up...

HTTP response: 403 | MIME changed to 'text/plain'

Wash off the purple paint off her left arm before you shoot the second shot!
From Picky CHEETAH

ZoranC wrote in post #16310465
I am not a guru on a topic nor I pretend to be one, but I do know that explosions in question were of flashlights that use multiple LiIon batteries and that were designed to use multiple batteries by the manufacturer. Those interested on finding out more can check CandleLighForums for start. From what I have seen explosions were rather violent. I might be wrong on whether it would make a difference here but bottom line is that because of what I have seen I never use flashlights or anything else that uses multiple LiIon batteries, I am walking around them in big arch and use only ones with single LiIon or ones with multiple NiMh.

The explosion is the result of gas/flame build up in a water-tight aluminum flashlight body. The weakest points are the tailcap and front glass, which becomes shrapnel.

In the L 4500's case, there are 4 holes on top of the battery where the gas vents upward without build up, and therefore, there will be no explosion. Though through those holes water can get in and cause a reaction. Trade offs. In case of catastrophic failure (like water shortage, physical damage shortage (from drop), and overcharge), stop the fire if safe, then leave the room without breathing too much, and then take a breath of clean air and go back in to open windows to vent the gas. Most incidents mentioned in CPF are the results of crappy batteries like Ultrafire and Trustfire (refered to as Ultrafail and Trustfail). BatteryStation— a battery company— experimented on scores of its own batteries, shorting them and drowning them on purpose. Almost all died after bubbles came out and that was it. Nothing dramatic. That showed Li-on usually die quietly (when killed before its lifespan), and does not go out with a bang. I'm betting the L 4500 is fine though.

Lithium is a way of life. They're in laptops that people put on top of their laps, they're in cellphones that people put inchs from their brains, and they're in cameras that people press on their faces. Just treat lithium with respect and keep safety knowledge in mind, and it'll serve the user with 3x the power/capacity as a NiMH batt.

I use 2 RCR123 li-ons in series with my UV L2T flashlight all the time. That LED likes the 7.4V more than 3.7V. I use a reputable charger so I know it'll charge both batts to the same voltage. Many flashaholics have voltage meters to check and ensure safety.

CheetahStand wrote in post #16312153
You will be the first one in USA!!

Yeah baby!

JaycYu wrote in post #16312319
The explosion is the result of gas/flame build up in a aluminum flashlight body.

That's not how I remember it. I might be wrong but I don't want to prove myself right. I will leave it to others to decide what they want to do for themselves. For me existing recycling time (with 2-to-1) is already fast enough, I don't find even slight risk of pushing things farther worth it to me. And I don't think manufacturer would condone use of equipment outside of prescribed manner / would accept warranty and legal liability if things go south due to it.

Battery packs have nice protective circuits inside them that disconnects the cells if they get too hot or the voltage goes out of range or the current gets too high. With the very few exceptions where there have been production issues resultin in battery recalls, almost all issues comes from either puncturing a battery, overheating it with external heat, or trying to goof with naked cells that doesn't have any supervisor chip in them.

I haven't followed your thread but it isn't unlikely that these flash lights are using some brand of Li-Ion batteries that for some strange reason either gets shipped without any supervisor chip, or with a supervisor chip that has been configured for a completely different size of battery cells.

When you play with something like a battery pack for a flash, then you are playing with a complete device where the manufacturer have to assure that you can't get the battery cells to catch fire without very serious external abuse. They don't need to certify it for customers taking a drill to make a hole through it, or customers connecting it directly to mains. But they do need to certify that it is safe for short circuit or if you there are issues with the cables so you get the polarity wrong.

So in the end, you can see the Cheetah batteries as very safe. How many walk around and are scared about the batteries for their cameras? Remember that any li-ion battery with a voltage of more than 3.6V is using multiple cells. So lots of cameras have two cells to get 7.2V. Computers often have 3-6 cells in their battery pack to get 10.8 .. 21.6V. Just that these battery packs have matched cells to make sure that one cell doesn't gets too depleted by the stronger neighbours and forces the supervisor to permanently disconnect the full battery pack.

pwm2 wrote in post #16313101
Battery packs have nice protective circuits inside them that disconnects the cells if they get too hot or the voltage goes out of range or the current gets too high. With the very few exceptions where there have been production issues resultin in battery recalls, almost all issues comes from either puncturing a battery, overheating it with external heat, or trying to goof with naked cells that doesn't have any supervisor chip in them.

I haven't followed your thread but it isn't unlikely that these flash lights are using some brand of Li-Ion batteries that for some strange reason either gets shipped without any supervisor chip, or with a supervisor chip that has been configured for a completely different size of battery cells.

When you play with something like a battery pack for a flash, then you are playing with a complete device where the manufacturer have to assure that you can't get the battery cells to catch fire without very serious external abuse. They don't need to certify it for customers taking a drill to make a hole through it, or customers connecting it directly to mains. But they do need to certify that it is safe for short circuit or if you there are issues with the cables so you get the polarity wrong.

So in the end, you can see the Cheetah batteries as very safe. How many walk around and are scared about the batteries for their cameras? Remember that any li-ion battery with a voltage of more than 3.6V is using multiple cells. So lots of cameras have two cells to get 7.2V. Computers often have 3-6 cells in their battery pack to get 10.8 .. 21.6V. Just that these battery packs have matched cells to make sure that one cell doesn't gets too depleted by the stronger neighbours and forces the supervisor to permanently disconnect the full battery pack.

This firm had a spot of trouble with Li-ion batteries: http://en.wikipedia.or​g …eamliner_batter​y_problems

When there is a control circuit on each pack then is save as long the circuit is not damages. I recall resetting my battery gauge on my tablet by shorting the battery...this took a lot of convincing on my part because I learned to NEVER EVER short batteries.

amplexis wrote in post #16311620
studio light with T1 1/20000 sec duration ! i'm ready to buy. i also want to buy a nice newAir-Gap flash.

with all the nice Arduino based controllers for high speed photography we need some short duration flash.

It seems that we have to wait to learn this till the specs are released.

mmmfotografie wrote in post #16313723
This firm had a spot of trouble with Li-ion batteries: http://en.wikipedia.or​g …eamliner_batter​y_problems

When there is a control circuit on each pack then is save as long the circuit is not damages. I recall resetting my battery gauge on my tablet by shorting the battery...this took a lot of convincing on my part because I learned to NEVER EVER short batteries.

It is always possible to find a link to back any side of an argument.
I'll add my own link of Li-Ion troubles:
http://www.bloomberg.c​om …fire-department-says.html

But what links fails to show is the relation between number of issues and total amounts of used batteries. Each link representing issues with Li-ion batteries should be seen in relation to tens of thousands of uses (not individual installations/devices, but total product lines) that hasn't issues with the batteries.

If I see a link of someone having been murdered, that doesn't mean I should spend my days inside assuming people gets swatted like flies all around me.

15 years ago, you had at least 5-10 huge companies every year who needed massive recalls of batteries, and a large number of smaller companies who never made the newspaper. Today, you almost never see recalls despite a market that is tenfolds larger than it was then. Ship a million li-ion batteries, and the expected outcome is zero fires, if ignoring people who intentionally wants to destroy the batteries.

But that doesn't stop companies from sometimes making mistakes. Like considering the environment where they will mount their batteries and how that will affect the temperatures when the batteries are charged. And sometimes, some company goofs and mismatch the configured parameters of the battery supervisor chips in relation to the battery size. And sometimes, some cheap company gets access to raw battery cells and decides to ship battery backs without any supervisor chip - still safe for normal use but now without protection from users who leaves their empty batteries for years and then tries to reawake a totally empty battery.

Somewhere along the line, Boeing made a mistake - easy to understand since they had to break a lot of new ground, and also base their systems on a battery design from 2007.

A large number of people have managed to explode their car batteries because they have put charge cables on the battery and then closed the hood, shorting the charge cables with the hood. But that doesn't really make it meaningful to consider lead-acid batteries better avoided because they are so dangerous. It's just a question of "don't do this" - similar to why people shouldn't use nails in their fuse box when they get too tired of a breaking fuse.

Most li-ion cell manufacturers have a contract that their customers may not further distribute naked cells - i.e. that the cells may only be sold complete in a package with supervisor chip. But there are still a number of channels available where hobbyists can get access to unprotected cells. Not dangerous to use as long as they are used according to their design. But without protection from people who let them drain too low, or who charges them with too high voltage or current. Or who keeps them in too hot environment while charging them.

amplexis wrote in post #16311620
studio light with T1 1/20000 sec duration ! i'm ready to buy. i also want to buy a nice newAir-Gap flash.

with all the nice Arduino based controllers for high speed photography we need some short duration flash.

http://usa.hensel.eu …sh-devices/speed-max.html

ramin.ma wrote in post #16314076
http://usa.hensel.eu …sh-devices/speed-max.html

http://www.bhphotovide​o.com …_Speed_Max_Mono​light.html

YIKES!

Besides being extremely expensive, they also only give that short flash pulse at minimum output power. It might be cheaper to buy a huge quantity of LEDs and transistors and design a 1us pulse flash (or to match the Hensel a 6us flash).

pwm2 wrote in post #16313101
So in the end, you can see the Cheetah batteries as very safe. How many walk around and are scared about the batteries for their cameras?

Please notice nobody wondered are Cheetah batteries safe, of course they should be safe when used in manufacturer intended manner. Question here was is it still safe to use them in manner that manufacturer didn't design for, intended and approved (connecting two L4500s with three 2-to-1) and how manufacturer would feel about warranty and legal implications of such use. Once again, to each his own, I am staying on officially approved side.

It should be safe, in regards to user safety. While maybe not representing intended use, they have to support quite a lot of erroneous connections without starting a fire.

But it might not be safe in regards to warranty, which was what I did talk about in my first post about this kind of use.