Why no LiPo battery pack flashlights?

[Hellbore]

All my electrical RC airplanes use these rectangular Lithium Ion Polymer battery packs that have leads on them with Deans Ultra connectors.

How come someone isn't making lights that you slip one of these packs into? The packs are getting more and more affordable and can handle very high current draw, and with the right charger they can charge up real fast.

Just curious. Seems like the battery packs with their own leads and connectors would be simpler, no more using the flashlight body for a ground and no more contact issues, so simple to wire up, no more battery springs, etc. etc. etc.

 

[rockz4532]

iirc, li-po batteries have a tendency to explode if shorted, driven at too high current, or charged at wrong voltage, so i think it is a safety hazard

 

[LukeA]

iirc, li-po batteries have a tendency to explode if shorted, driven at too high current, or charged at wrong voltage, so i think it is a safety hazard

All of those are also true of li-ion, the explosion being even worse with li-ion, because of the pressure vessels that contain them. Li-poly cells puff up and leak.

Too high a current for a li-poly pack can be upwards of 50C, which might end up being 100-150A.

I'm putting a li-poly pack in my 10 Cree light. It can supply the wattage I need and still charge easily and be light.

I think li-ion cylindrical cells are more popular in flashlights because it's easier to make those parts.

 

[qwertyydude]

It's also that they're delicate, if you poke them with something sharp they're liable to blow, also they need to be strapped down and cushioned. A good drop would put a dent in the corner and on a subsequent recharge they also risk blowing up. Another is big reason is that the dimensions and connectors are not standardized. I would say that you get all the benefits of li-po with A123 except they charge ridiculous amounts just so you can be a reseller so it hasn't taken off like they kept trumpeting a few years back.

 

[Gunner12]

The shape might also be a factor.

It is easier to machine round things then rectangular things.

 

[Hellbore]

Yeah good point about A123 batteries, those things seem to have a ton of potential, too bad they haven't taken off.

 

[Fird]

Li-po = if you want a hotwire, the added current capacity is great! I'm not sure if technology has improved, but Li-ion seems to still have better capacity for a given size, which increases runtime for these LED lights anyway at 1-2A discharge. Over in incans you might find Li-po does better (5-20A current is common for hotwires).

 

[FlashCrazy]

I think the biggest factor is being too fragile. Sliding one in and out of a flashlight many times would surely chafe through the wrapper.
If you cushion or wrap them sufficiently, then they would probably be too fat. Not to say I haven't thought about building a hotwire using one... I have at least a couple of dozen Li-Poly packs here.

 

[Hellbore]

I think the biggest factor is being too fragile. Sliding one in and out of a flashlight many times would surely chafe through the wrapper.
If you cushion or wrap them sufficiently, then they would probably be too fat. Not to say I haven't thought about building a hotwire using one... I have at least a couple of dozen Li-Poly packs here.

Oh really why do you have so many? Do you use them for RC cars or planes or boats or something like that?

 

[FlashCrazy]

Oh really why do you have so many? Do you use them for RC cars or planes or boats or something like that?

For planes, my other $$$ hogging hobby.

 

[chuck614]

The criticisms leveled at LiPo's have not been true in my experience. I asked the same question some time ago and got the same response in thread 188521. I went my merry way and did what turned out to be one of my favorite builds at 194251 with pix.

I would like to see some LED builds with LiPo's--give them a try!!

(Sorry about no link--I couldn't figure out how)

 

[qwertyydude]

I actually have a single lipo powering my 75 mW green laser. It's glued to the bottom, but I'm really careful with it. I've had one swell before just from getting a corner bent in when it dropped on the ground. But they just don't have the energy density as li-ions so that coupled with the fact that if you were going to surround them in cushioning and hard casing like some companies like Team Orions carbon fiber packs makes them about on par with advanced nimh batteries but just a little bit lighter.

 

[Holzleim]

I buil the light linked in my signature with small LiPo cells as well as a 5x XR-E light powered by 4x 3,2Ah LiPo cells.
I integrated charging electronics and USB plug for charging and till now I can't say anything bad about the LiPo.
They offer high current capabilities, are easy to charge when one of the broadly available charging ICs is used, have small self discharge and acceptable life cycle.

 

[Hellbore]

Nice work Holzleim that's very cool!

 

[chuck614]

http://www.candlepowerforums.com/vb/showthread.php?t=194251

This thread might need to be moved to flashlight electronics.

 

[Hellbore]

Yeah I didn't know where to post, I was specifically wondering about the viability of lipo packs in an LED light, but the topic has sort of shifted towards lipo packs in general I guess, using them in incans etc, even though I was only thinking about LED lights originally. Maybe as it stands now, it would fit better in the other forum.

 

[orcinus]

The shape might also be a factor.

I think this is the main reason.
Stuffing a square peg into a round hole isn't exactly the optimal use of space

 

[sunny_nites]

Funny you should mention a flashlight running on a LiPo...

I built a few keychain lights that use a 100 ma LiPo battery with a built in charger that runs off of a USB Mini port.

I've been using them for over a year and they work great. I use at least one several times a day. The LiPo is built in and not meant to be removed. It is also encased in a steel "cage" to protect it.

They use a 7 LED array from a 12v rechargeable light from Walmart. The array is similar in brightness to a LED MiniMag running on low. I was going to post some pictures but I'm new here and haven't figured out how yet.

 

[KuKu427]

Here's two.

http://www.candlepowerforums.com/vb/showthread.php?t=238888

http://www.candlepowerforums.com/vb/showthread.php?t=259385

 

[Saint_Dogbert]

The 4sevens Maelstrom S1200 is supposedly going to run of of LiPo when it is finally released. According to this webpage, phosphate batteries have a lower energy density than the ubiquitous LiCo chemistry, but can sustain a much higher discharge rate, and have improved cycle life.