LiFe battery question

[coach]

Originally Posted by Kos-Mos

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...

my understanding is that LiFe batteries have circuitry on board (at least with the Intellects and Madbulls) to prevent over discharge. So you're not actually draining it to 0%

[Wildlife]

So, I went with scurvythepirate's suggestion (assuming it to be the easiest).
[/begin detailed elaboration:]
First order was mounting the stock to my receiver (G&P SR-25) securely. I had to shim the UBR's stubby AEG buffer tube for a snugger fit with the stock tube (I used 1mm UHMW tape, fits very tight with no wobble, still slides off nicely when needed). Then I wanted to reinforce the stock tube to buffer tube mount; accomplished by drilling through the assembled unit through two unused cheekrest mount holes into my receiver, tapping the receiver, and countersinking the stock tube holes. Now it's held securely by two screws right through all three parts.




Incidentally, I found it necessary to mill the receiver key down by 0.5mm (.020") for a gap-free fit with the receiver.



To fit the battery ("Flame" brand 9.9V 800mAh LiFePO4), I had to make 10mm more room inside the stock tube. I made 4mm by counterboring the buffer tube so the screw head fits flush. Had to cut 4mm off the threaded end of the screw to make up the difference.




Milled 7mm off the stock tube end-cap's inner face.



For easier access to the battery, I tapped the hole in the end-cap (originally for a pin, happens to be pre-drill size for an M3x0.5 tap), and counterbored the stock tube holes so the screw heads sit flush with the rail.





Now I just pull the stock body off and remove 2 screws to swap batteries. [/end detailed elaboration]

Blah blah blah. It works!

[Azathoth]

Can you shoe me a shot of your battery pack? I considered A123 batteries for my UBR (production model) but discounted it since I couldnt find a pack or cells that would fit. I have quite a bit more room in my UBR to fit batteries than on the prototype model UBR. However I am running a trigger master that is in the storage compartment of the UBR.



That is a old picture, the wiring is more discreet now. I could do some work to the stock pipe so that It's completely hidden but I have held off for now not wanting to really mess things up.

[Wildlife]

Looks like yours, but a single pack (three strips wrapped together). I didn't try the A123s yet, still might if I'm not happy with these. But this way I keep the stock compartment empty and all the wiring confined to the stock tube. I've ordered an AWS "stealth" MOSFET that fits entirely in the gearbox, as there's no room anywhere else.

[Azathoth]

Can you send me link to where you bought the battery pack. Your pack *looks* significantly smaller than the one I have pictured

I want the TM 3.8+ features, I asked him to add all of the LiPo features onto his board, and the on/off for active breaking a year ago and got the 3.7-3.8 boards for testing.

With the tri-panel and some select Duratrax Battery packs you don't need to remove the stock body off the buffer tube to get the batteries into place.

[Wildlife]

Bought from KHMountain (link), also available at RSOV (link).
I wanted a simple MOSFET for now, might upgrade to a "bells & whistles" model later. Liking the idea of a zero-footprint, "invisible" MOSFET and a new trigger assembly in one easy(ish) step.

[coach]

Originally Posted by Azathoth

I considered A123 batteries for my UBR (production model) but discounted it since I couldnt find a pack or cells that would fit.

have you tried 2/3A cells and have it custom made to your configuration? 2/3A is what most call mini's.

[Azathoth]

Originally Posted by coachster

have you tried 2/3A cells and have it custom made to your configuration? 2/3A is what most call mini's.

I looked into AK style stick batteries but with in a "sectioned staff" configuration. The pack would just be too long to be contained in the buffer tube. Lithium batteries of some kind is what is going to be needed, short of some super expensive batteries that are being used in the oil and gas industry.

I play hardball on a irregular basis and you can't pull a 600+ FPS ( Airsoft Surgeon stage 6, discontinued :cry: ] spring with a 9.6v Nickel battery of any kind. Commercially available, and cost effective Nickel batteries just cannot deliver the power required by the system. The LiPo I have pictured doesn't provide the power required, likely because it's a chinacrap pack with awful C value (8-12). With quality 11.1v+ packs I have no problem running hardball guns at 18-22bps

On my standard setup, I use the trigger master to slow the motor down and get a more reasonable rate of fire. My setup needs to be able to handle the different setups that I play under, and Lithium seems to be the only way to go.

[ThunderCactus]

Most LiPo's small enough to fit inside a buffer tube will have a low C rating regardless of who makes them, but better companies do have higher C ratings. However it's based on the physical surface area of the pack, just like it is with NiMH batteries.
A larger surface area allows for more reaction, and therefore more power
(sorry if you already knew that)

I totally agree with you that LiPo is the best way to go for best performance, especially switching between 400 and 600fps springs.
Have you considered putting a stock mag pouch on the gun and running your wiring into that? It's allowing me to use the 11.1v 20C 4900mah battery from my 249 on my M4.
Personally I hate having to change batteries lol

[Azathoth]

Originally Posted by ThunderCactus

Most LiPo's small enough to fit inside a buffer tube will have a low C rating regardless of who makes them, but better companies do have higher C ratings. However it's based on the physical surface area of the pack, just like it is with NiMH batteries.
A larger surface area allows for more reaction, and therefore more power
(sorry if you already knew that)l

Yeah I did know that. But it's a good idea to have it here for people who don't. The C value on buffer style packs @ 11.1 (generally 8-12c) is just enough to get the gun shooting for a while on standard limits across Canada. Those ACM Hot power etc packs and even the 'intellects' that Huang, and Duey sells are not that great. I just don't trust the C or Mah Ratings on those and have ended up tossing 3 of those el cheapo packs.

Based on their rated Mah and C, I get about 200-300 rounds out of the pack before it's useless

In LiPo, you especially get what you pay for.

I've found that at ~1.7Joules which was the limit for Mason Relic 1 a 7.4 with a decent amount of mah 1800+ and C around 20, can turn the gun around. However, the pack will not have enough power to cycle the gun before it drops below 6v so no need for a low voltage warning, although you should still run one.

Originally Posted by ThunderCactus

I totally agree with you that LiPo is the best way to go for best performance, especially switching between 400 and 600fps springs.
Have you considered putting a stock mag pouch on the gun and running your wiring into that? It's allowing me to use the 11.1v 20C 4900mah battery from my 249 on my M4.
Personally I hate having to change batteries lol

Actually moving to a mag pouch with a brick style battery is what I did. Running a zippy 2200mah 20C battery is enough to get the job done at hardball setup, and more than enough for standard play if I slow down the motor via trigger master.

A friend of mine uses this pack for hardball, it's from his RC crawler or chopper.

[Gunny_McSmith]

Originally Posted by Azathoth

Can you shoe me a shot of your battery pack? I considered A123 batteries for my UBR (production model) but discounted it since I couldnt find a pack or cells that would fit. I have quite a bit more room in my UBR to fit batteries than on the prototype model UBR. However I am running a trigger master that is in the storage compartment of the UBR.



That is a old picture, the wiring is more discreet now. I could do some work to the stock pipe so that It's completely hidden but I have held off for now not wanting to really mess things up.

You should get a AWS airsoft Stealth mosfet(LINK) ... :P

[yoyit2]

Tenergy Makes a 11.1v 1200mah stick type @ 20c = 24A
http://www.all-battery.com/111volt-1...pack31268.aspx

mackoutdoors.ca sells 7.4v 1200mah stick type @ 20c
http://www.mackoutdoors.ca/products/...k-Type%29.html

kinda off topic, but to be honest i had some fun with lipo torture testing (safe environment) i charge up a 1500mah 11.1v zippy battery 30c, and purposely shorted it!!!! within seconds, it swelled up a bit, and ALL the solder on the battery instantly melted, leaving the cells disconnected. its kinda like an unintentional fail safe lol

Lipos are WAY safer then people make them out to be. respect lithium based batteries for what they are, and have fun with them!

as far as li-ion goes, the reason they are "safer" is because they are PCB protected :P - small circuitry that regulates there voltage

alot of new laptops/netbooks/smartphones - even iphone 4 use LiPo!! - yes that means more then 3,000,000 people are walking around with LiPo's in there pockets, as we speak.