LiFe battery question

[Wildlife]

I'm looking at some LiFePO4 batteries (here) that would just nicely squeeze into a UBR stock tube with minor modification. Claimed to be 3.2V/2000mAh/10C; does anyone know if three of these could power a gearbox for a decent time? I read somewhere on here (can't find the thread now, of course) about LiFe batteries having too low a discharge rate for AEGs (can't draw a high amperage for long); most of the LiFe cells I've seen offer 1 or 2C. These claim 10C, though I believe 15 or 20C is typical for LiPos.
LiFePO4 cells are supposed to be much safer than standard LiPos, which is why I'm considering them.

The specific application I'm looking at is a DMR setup: SR25K with a V2 gearbox pulling a M120ish spring (400fps-ish). Retaining full-auto would be nice; I don't know if these cells would hold up though.
Apologies if this is a poorly worded idea, my understanding of battery chemistry is about 20yrs out of date.

[Danke]

I can't speak for the battery in your link but I did switch my VFC SCAR to Life batteries this fall. It has a tiny compartment and would only fit a mini battery. Said battery would last half a game. Now with the Life I can run all day and have power left in the bag.

http://www.airsoftparts.ca/store2/in...oducts_id=1259
is what I got.

http://www.airsoftparts.ca/store2/in...oducts_id=1069
is what I had.

Night and day.

[liquidgenesis]

All Lithium batteries will outlast similarly capacitied nickel battery. They are more efficient and have much lower internal resistance than nickel batts. This is evident in the fact that nickel batts heat up when in use, lithiums do not.

Plus that 10C rating far surpasses any nickel battery amp output. I read in one of my RC car magazines that NiMhs only output roughly 2-5C depending on quality of cells.

[Wildlife]

Originally Posted by Danke

I can't speak for the battery in your link but I did switch my VFC SCAR to Life batteries this fall. It has a tiny compartment and would only fit a mini battery. Said battery would last half a game. Now with the Life I can run all day and have power left in the bag.

http://www.airsoftparts.ca/store2/in...oducts_id=1259
is what I got.

http://www.airsoftparts.ca/store2/in...oducts_id=1069
is what I had.

Night and day.

Hm, the battery you linked says it's a standard lithium-ion-polymer type; I'm looking at lithium-iron-phosphate batteries (different internal chemistry). Just curious if anyone's got experience with this type of cell, they're supposed to be much safer than regular LiPos.
I think I could stuff 2 of these cells in a UBR stock tube, with one or two more in the storage compartment; might still have room for a MOSFET if I'm lucky.

...If anyone knows a Canadian supplier of these cells, I'd much rather buy in-country...

[scurvythepirate]

Couldn't find one in country, but this should fit.
Its a LifePO4 battery, just as you asked.
http://www.rsov.com/index.php?target...oduct_id=12926

[ThunderCactus]

LiPo batteries are safe, people are not.
You put gasoline in your car don't you?

[Kos-Mos]

LiFe batteries that fit in a buffer tube are usually too small capacity to be worth anything.

If you can fit an A123 cell in there, you would have awesome power though...
They are 2300mAh and 45C+discharge rate. And you can charge them at 10C (yes, 23A charge). Cells are a bit large than regular Sub-C cells so I don't think it would fit properly.

[Conker]

I've been running 1300 mAh 9.9v LiFe batteries since... october I think. That's about 4 games. No problems as far as batteries go... Some problems with my gun, but the batteries worked well

But then I'm not a "spray'n'pray" so this might explain a bit why.

[Danke]

Whoops,

http://www.airsoftparts.ca/store2/in...oducts_id=1807

[Wildlife]

Originally Posted by ThunderCactus

LiPo batteries are safe, people are not.
You put gasoline in your car don't you?

Don't currently own a car. :P But you got it in one; I'm as safe as the next guy (he's missing several fingers...) Just ask this firearms safety instructor in Ohio; everyone screws up now and then. And I'm a moderately paranoid kinda guy who's hard on his equipment. (You know those "indestructible" titanium eyeglass frames? I went through three sets in a year. Got a shoebox full of broken multi-tools that couldn't survive a year on my belt.)
But I digress.
@scurvythepirate, that's a perfect fit. Inside of (clone) UBR stock tube measures 28.5mm dia. X 105mm long with AEG-type buffer tube & screw installed. Is only 800mAh though; also not a hard-cased cell. (I'm told the soft-pouch LiPos produce oxygen when over-discharged & recharged; this builds up between lithium & electrolyte layers, resulting in delamination/swelling and aforesaid risk of fire. Metal-cased cells are supposedly immune to this.) Probably my easiest option though; why I no find this?!

@Kos-Mos, I'm liking those A123s; the cells are huge though; 26.2mm X 65.4mm, or 22650 size. Might be able to cram two in the stock tube with some creative tinkering (Countersink screw, mill down endcap.)

@Conker, what sort of charger do you use? Did you need a MOSFET?

I believe I could modify the stock tube's rear cap to flip open for quick & easy access to battery; If it works I'll post pics.

[ThunderCactus]

If you don't over-discharge, puncture, over current draw, short it out, or charge it after any of the previous has happened , it won't catch fire. Same goes for LiFe, LiPO4 and Li-ion.
The only big advantage NiMH has is that it won't go up in smoke because of over current draw, and you can drain them right dead and charge them back to life.
If your going with a soft shell LiPo, it's going in your buffer tube, it's pretty safe in there lol

[Kos-Mos]

Originally Posted by ThunderCactus

If you don't over-discharge, puncture, over current draw, short it out, or charge it after any of the previous has happened , it won't catch fire. Same goes for LiFe, LiPO4 and Li-ion.
The only big advantage NiMH has is that it won't go up in smoke because of over current draw, and you can drain them right dead and charge them back to life.
If your going with a soft shell LiPo, it's going in your buffer tube, it's pretty safe in there lol

LiFe can be over discharged, drained to zero and are still good. And I don't know how you can overcharge it... it takes 23A to push it too far...

The cells are quite big, but might fit with a modifiec buffer tube... Wires will be the tricky part...

You said you wanted to use an UBR stock? I guess there is something so be done with it... shaving most of the metal tube off the tube and using only the plastic cover for tube... Would need a machinist of some serious dremel work.

[ThunderCactus]

I'm a machinist lol
Speaking of UBR's, mine's actually the prototype model for the airsoft version.
It was a cylindrical cap that bolted to the back of the receiver, and the UBR was held onto that cap by the 2 forward screws it uses to keep the plastic cover on the buffer tube lol
Drilled a hole through the side of the tube, put a rod in there with a hole in it's side and secured it to the receiver through that.

YEAH sidestory.

I didn't know you could drain LiFe cells, learn more everyday lol
I didn't mean overcharging, I meant in the case of LiPo's where charging a damaged pack causes fire.

What I'm doing to my M4 right now is mounting a mag pouch on the stock and running the wires into it to run my LiPo/triggermaster from there.
11.1v 4900mah battery.....doesn't quite fit in an ANPEQ or buffer tube lol

[Wildlife]

Originally Posted by ThunderCactus

I'm a machinist lol
Speaking of UBR's, mine's actually the prototype model for the airsoft version.
It was a cylindrical cap that bolted to the back of the receiver, and the UBR was held onto that cap by the 2 forward screws it uses to keep the plastic cover on the buffer tube lol
Drilled a hole through the side of the tube, put a rod in there with a hole in it's side and secured it to the receiver through that.

Yeah? My clone UBR (from out-of-country, didn't know Huang was selling them) came with two buffer tubes:
one is full-length (190mm) & threaded for GBBR receivers, the stock mounts with one M6 countersunk screw through the endcap into the end of the buffer tube, similar to real-steel
and one "stubby" (68mm) with M5X85mm screw for AEG receivers, the stock mounts with two small grub screws through the underside of the stock tube that bite into matching divots on the underside of the buffer tube. (Kinda weak setup imho.)



With the AEG buffer tube in place, I've still got 28.5mm X 105mm of empty stock tube; plus there's a slot running the length of the tube's bottom I can stuff the wiring into. It occurs to me that simply backing off the two grub screws would give access to any batteries stored behind the buffer tube (dur), so modifying the stock tube end cap to flip open would really be a waste of time. :banghead:

Heh, still not sure I even want this on my SR25K... not a Magpul fan normally, but this stock sure is comfy. Heavier than my full stock too, should help offset some of the front-heaviness of a PEQ & bipod.

Whoops, off-topic(-ish). scurvythepirate's linked battery would fit easily, but 800mAh is a bit low for my liking. They've got a 1000mAh version, but it's 125mm long; I'd have to mill out a lot of material & weaken the stock tube considerably to fit it. I like the A123 cells, but could only fit one in the stock tube... maybe two more in the stock compartment. Hmm.

[ThunderCactus]

Yeah mine was the same setup without the divets. Extremely weak, would not trust a sling on it AT ALL.
I've seen the GBBR style as well, installed one on a STAR M4.