Li-PO battery ???

[Kid]

How many times have you had some miss-hap inside your gun and had your battery heat up after trying to do a full auto burst?

Now, if it's like me, and it is once or more, think about the same thing happening, with a Li-PO, and not having an arm.

At least, then it only happens once.

[CDN_Stalker]

Personally, I wouldn't want a Li-Po battery near my face or body. They are sensitive and can go for no reason at all.

YouTube - LIPO BATTERY

More susceptable to overcharging, but there are enough cases where the battery decided to blow up on it's own accord. Too unstable to trust, even if one knows what they are doing and are careful.

More here:

http://www.youtube.com/results?searc...y=lipo+battery

[Jayhad]

Ya after viewing those videos............ if I wanted to have all my gear on and play with guns and possibley get really hurt I think i would join the CF, not let a battery take off half my face.

I guess i am back to using AUG custom batteries, just have to carry a second one

[LUTNIT]

They seem stable enough to trust in cell phones and PDA's....a pile of em have them in them, two of my friends cell phones have LiPo's in em instead of LiIo's and two other people I know have LiPo powered PDA's.

Also you wont loose your arm, you will badly burn your hand and die from the incredibly toxic gases that are released. Also keep in mind cheap packs blow far more often than good ones. I have been told stories of R/C planes crashing nose first at terminal velocity and the LiPo battery came out and was used again many times with no problems and also catastrophic R/C car crashes that destroy every aspect of the car but the battery comes out fine. There was also a story of a guy using a LiPo in his MP7, put a tiny little scratch in it when inserting it into his gun and it blew right there, chances are that was a dead cheap bottom of the barrel Chinese made LiPo pack, not the good ones by far. A cheap NiCd or NiMh pack, worst case scenario, it pops and leaks battery acid everywhere (actually more common than LiPo's exploding) but worst case with a LiPo is a lot worse.

-Balance the cells during charging
-Use a good charger (talking $150-200 here)
-Buy top quality LiPo packs, not cheap ones
-Don't man handle your battery (I've seen some really torn up and dented NiCd/Mh packs some players use)
-Use proper charging amperage (LiPo's you want to charge at 1C at maximum, lower is better)

Follow that and the chances of a LiPo blowing up are around the same as the chances of a nickel based pack blowing up, only major difference is the consequences.

[Kos-Mos]

I did exploded a Li-Po pack once. It sent metal parts into the wall 85 feet away and went through the drywall.

But I also did crashed 2 planes using the same Li-Po pack. Once the pack actually blew out of the nose of the plane. I stil use this pack in my AEG and some R/C cars/planes.

The videos you see of Li-Po's bursting in fire are actually almost always tricked. The most common thing that could happen is having the pack inflate due to over discharge. It would eventually open and leak some toxic gases. But theses cells are just like condoms...they will stretch like 2-3 times their original size before leaking. Now if you are dumb enought not to remark it (it will not do it after just a single over discharge, except maybe some cheap ass li-pos.

You can get a very good charger for only 100$. You can use a "non-balancing" charger along with a cell balancer. I am using an Intellipeak ICE with an Astroflight "Blinky" balancer. Works perfect, but a 100$ charger (like the one from Thunder Power) works fine. It also balance the cells at the same time.

As for quality, I recommend you to get some Thunder Power Xtreme series packs. They can discharge at a great 20C and you can fit a 7.4v-2180mAh pack in the space of a mini. In an AUG you can fit a 11.1v no problems.

Don't buy anything under 15C. It will not deliver enought current and will inflate.

Last thing. Buy some heat shrink and re-wrap you pack to have at least 2 layers over the plastic/alloy cells. It will protect your pack from a lot of abuse. Most good quality packs are already like that, but some are not (like Thunder Power, only 1 layer)

I think I had more damage caused by Ni-Mh/Ni-Cd packs than whatever could have append with Li-Po cells yet. Li-Po's ARE NOT IMPREVISIBLE! Just like Nickel based cells, they will heat-up before having problems, they will start having issues like low capacity and inconsistent charges before dying.

I think that if I had to choose between a good Li-Po pack and a good Ni-Mh pack, I would go Li-Po 100% of the time. They are not more fragile or harder to take care than any other cells type. It is just not the same things you have to do.

*edit* NO YOU DO NOT HAVE TO DISCHARGE LI-PO PACKS ON A REGULAR BASIS. IT ONLY SHORTEN IT'S LIFE AND GIVES AN EXTRA CHANCE TO CAUSE FAILURES. BALANCING THE PACK EVERYTIME YOU CHARGE IT IS THE ONLY THING YOU HAVE TO DO IN THIS DOMAIN. A SINGLE DISCHARGE CAN BE GOOD AFTER A LONG PERIOD OF INACTIVITY, THAT'S ALL.

sorry for the caps..just to make sure everyone get that.

[Gryphon]

Originally Posted by Kos-Mos

They are not more fragile.....

Come again?

YouTube - Lipo (Lithium Polymer) Battery Fire through mechanical Damag

[Kos-Mos]

Yeah...just do the same with Ni-Cd cells.

I can bet you 100$ that they will spill acid everywhere.
The only difference is that Lithium is flammable in contact of water. The humidity in the air is enought to ignite it.

Just try it. But remember to record it. I want you to blast a Ni-Cd cell just like they did. With a pole and a nail.

This is what I ment by almost all the videos are fake. Thing like that would never append in a normal situation.

[MadMax]

Originally Posted by Gryphon

Come again?

http://www.youtube.com/watch?v=4OsBc8RqSKU

I think there's a in the end of the stick which puctures the pack pretty severely. It's not exactly a fair test to show reasonable damage.

LiPo packs are more sensitive to physical damage than NiCd or NiMh owing to their thinner separators. A frequent issue in R/C helicopters is damage caused by simple inertia in a crash. In a decently hard crash, lipo packs can be damaged by their own inertia (not slammed by something else). This usually doesn't cause thermal runaway, but the pack fails to store charge.

[LUTNIT]

You said a voltage cutoff is only about $10, where does one buy one of these? I know where to get the packs and balancers but not the cutoffs.

[Kos-Mos]

Well... most cut-off used for hobby are not powerfull enought to run as a direct switch.

You would need to wire it to a mosfet or some high power transistor to allow it to take the high currents involved.

I don't remember what is the brand, but I found a nice little one, about the size of a gum. It is programable for 1-4 cells, perfect for the us we want.

[HaZarD SFD]

There is a huge writeup on Lipos here on ASC I will get the link!

[Gryphon]

Originally Posted by Kos-Mos

Yeah...just do the same with Ni-Cd cells.

I can bet you 100$ that they will spill acid everywhere.

I'll take that bet considering there isn't any "acid" in NiCd cells. There are bases consisting of potassium hydroxide and nickel oxyhydroxide in addition to the cadmium anode. KOH is caustic and can cause chemical burns but I guarantee you hitting one with a nail through a board, assuming you could even get it to puncture the thick casing of the cell, will not erupt with a massive jet of flame that will give you horrible third degree burns.

You are minimizing the danger of LiPo batteries for no apparent reason. They are an immature cell technology (just ask Sony and Dell) and users should be made aware of the risks they face if they decide to use one. Personally I can do without a miniature incendiary grenade sitting next to my head as I fire.

[HaZarD SFD]

OH this will be an interesting thread!

[LUTNIT]

Sony and DELL? I thought it was LiIo packs that screwed up and not LiPo.

[Kos-Mos]

Originally Posted by HaZarD SFD

OH this will be an interesting thread!

Don't worry, it already is.

There do is some corrosive liquid that will spill out of damaged Ni-Cd. The normaly solid catalyser heat-up under the excessive current caused by the internal shoring, and liquify. Burnt the top of a desk because the charger failed to stop. I can tell you that this was liquid when it came out of the pack. I will try to find the pictures of my friend's R/C car. A pack melted it, he had to change the chassis, center drive shaft and rear gearbox.

I wouldn't mind having a grenade next to my head, mostly because it is safe as long as you keep the pin in.
Same goes for Li-Po. As long as it is not abused (You can drop a pack on the ground... probably nothing will happen) and protected enough, it is as safe as any Ni-Cd/Ni-Mh pack. I don't know for you, but my packs are most of the time under a lot less stress when INSIDE the gun than when it is charging.

You can't stand to have a stable element in your gun, but shooting your GBB with a flammable gaz spraying out is ok.

Whatever the way you look at it, it is far more dangerous to shoot a pistol on Propane than to plug a good quality, well maintained Li-Po in your gun. This last video is as stupid as some kid tapping a lighter under his GBB.

Where is the battery in most of the guns? Fore grip and stock. Take an M4, since most people have this. Have you ever heard of someone breaking the gun in 2, in the middle of the foregrip??? And also bend the outer barrel at the same time enought to make it piecre through the pack????

Anyways. I am sick if arguing. I am using Li-Po. Do as you want, it's only your loss. I get twice the capacity for the same space and a lot higher drain rate.