LiPo Battery Thread

[arcanuck]

Hello, I am going to write briefly on the topic of Lipo batteries as to help you understand more about them.

Lithium Polymer batteries offer some advantages over previous battery technologies. Increased run time and higher voltage vs. size and a lower weight penalty are some of the advantages achieved.
There are some trade-offs though: The higher capacity is proportionally offset by the lower available amperage than comparable NiCd or NiMH due to relatively high internal resistance. I personally like NiCd batteries as they have proven reliable in wars and less than ideal conditions. The leading cause of battery failure is modern cheaply corporate engineered chargers. General life expectancy of a good Lipo is 24 months but may vary.

The relevant specifications for a Lipo are given in this form:

11.1V 1500mAh 15C

This battery has a normal voltage of 11.1V and 12.6V when fully charged. 1500mAh (1.5A) capacity and can safely discharge at 15 times its capacity for short periods WITH PROPER AIRFLOW= 22.5 Amps. (Maximum discharge rates will vary by product and manufacturer anywhere from 2C to 40C) If a someone was to run a motor that draws a full 22.5 Amps that battery will de discharged in about 4 minutes 40 seconds in theory.

A similar sized NiCd may allow us 50 amps of current draw for short periods, a NiMN around 35 amperes.This is useful for knowing the limit of work your battery can do for you. Using a motor that draws too high amperage or is under too much load can damage the Lipo battery or worse. Lipo batteries are not considered “dead” when they have no measurable voltage left. They are dead when each cell reaches 3V. They are fully charged when each cell holds a steady 4.2Volts. So, a 3 cell 12.6V (11.1V) battery will be dead when it measures 9V and a 2 cell would be dead at 6V.

Disclaimer: In practice I would never approve of the use of Lipo in Airsoft due to the inherent possible dangers from shock/ impact damage, and chance of overdischarging without a regulator.

*Never drain a battery below 3V per cell.
*If your motor overdischarges or overloads the battery(s) it will shorten the battery’s life and may immediately cause separation of the hydrogen in the poly electrolyte. This poses a fire or explosion hazard.
*Never charge a Lipo unattended.
*Make sure the batteries do not get hot enough you cannot hold them comfortably.
*Never charge with a charger not specified for Lipo batteries.
*Lithium Ion chargers CANNOT charge a Lipo battery safely. Lipos require a 3 step charging process that is preprogrammed into a proper charger.
*Lipo batteries should NEVER get hot during charging. Not even lukewarm.
*Never charge a Lipo battery at an amperage rate more than 1xC the battery's complete capacity. Example: 12V 800mA battery; It is safe to charge this battery at 0.8 Amps max. Most qualified personnel agree never to charge at more than 1.0 Amp rate regardless of capacity. It may take longer but at least it will not pose a danger.
*Never short (connect) the positive electrode to the negative electrode.
*Never drop, stab, knead, twist, walk on, eat or throw a Lipo battery.
* Abusing above warnings can cause the battery to become unstable and swell or become hot. They can catch fire or explode into a white fireball that will even burn concrete. Occasionally they have been known to shoot burning hot electrolyte upon swelling.
*If it begins puffing up get away from it. And wait for it to settle. Contact a local engineering firm or recycler on how to discard it in your area. Never throw in the garbage.
*”My friend’s dad’s brother’s boss said blah blah stuck wires together blah blah and did this and it didn’t catch fire”. That is fortunate for them. Many others were not so lucky.


If you cannot clearly understand the terms and everything that has been said, it may be best for you to choose a different battery type for your safety. That is the number one priority.

[Auhydride]

get a liposack too
http://www.liposack.com/
it looks good, no personal experience though

[Jimski]

thank you arcanuck ! this is useful.

[808]

To offset some of the dangers around using LiPo batteries for Airsoft, I strongly recommend installing a Trigger Master fire control computer.

I use a Trigger Master in my LiPo guns, and The overcurrent/overheating/and over-discharge protection it offers is second to none.

I recently had an opportunity to review the Trigger Master Mk.I, and now the Mk.II - and they are without a doubt the best thing I could ever have installed in my AEG to protect it (and myself) from the dangers of using a LiPo while I play.

For charging, I use an iMax B6 charger. It is relatively inexpensive, and works very, very well.

Depending on the AEG you use a LiPo in, you may (or may not) need to modify the internals of the mechbox.

[Dusti69]

Originally Posted by arcanuck

*If your motor overdischarges or overloads the battery(s) it will shorten the battery’s life and may immediately cause separation of the hydrogen in the poly electrolyte. This poses a fire or explosion hazard.

* Abusing above warnings can cause the battery to become unstable and swell or become hot. They can catch fire or explode into a white fireball that will even burn concrete. Occasionally they have been known to shoot burning hot electrolyte upon swelling.
*If it begins puffing up get away from it. And wait for it to settle. Contact a local engineering firm or recycler on how to discard it in your area. Never throw in the garbage.
.

wow.... like kaboom?

i dont like my 11.1v lipo. ill only use it in one gun and only in semi. and to correct a guns firing when it stops and does the clicking thing and a burst on full auto doesnt fix it

its just way way too much power that you dont need most of all of the time and i dont need my gearboxes/parts wearing out any faster. i already stripped all the teeth off of an echo 1's piston from about 3 short bursts on full auto and had to buy a new piston

[808]

Originally Posted by Dusti69

...i already stripped all the teeth off of an echo 1's piston from about 3 short bursts on full auto and had to buy a new piston

I did that with an Echo1 piston, Classic Army piston, and a Tokyo Marui Piston with my 3300mAH 9.6V NiCd.

I have yet to strip a piston's teeth with any LiPo I've used, and none of the internals have shown signs of advanced wear on any of the 3 guns I've used LiPos in.

But, not all guns are made equally, and I'm sure in time, I'll start seeing some kind of wear.

[arcanuck]

Originally Posted by Dusti69

wow.... like kaboom?

i dont like my 11.1v lipo. ill only use it in one gun and only in semi. and to correct a guns firing when it stops and does the clicking thing and a burst on full auto doesnt fix it

its just way way too much power that you dont need most of all of the time and i dont need my gearboxes/parts wearing out any faster. I already stripped all the teeth off of an echo 1's piston from about 3 short bursts on full auto and had to buy a new piston

Yeah the gearboxes' motors where designed for lower voltage and consequently slower motor startup. The shockload that can be generated with more power/higher rpm will strip gears. On my airplane that I built, I use Lithium Polymer and have the ESC (motor control unit) set to slow response SO if I hit the throttle by accident the 1/5Hp motor doesn't tear the gears apart, break the propeller or flip the plane on its side.. I recommend using a large 2 cell (7.2V) instead of a 3 cell (11.1V). Or just normal NiCd. Using proper resistors to correct a 11.1V battery's voltage isn't cost effective.

[Kos-Mos]

Just a quick question.

How long have you been playing airsoft.

I have an extensive background in R/C, and I can tell you that these are two different worlds.

All my 7.4v I tried had overheat and poor performance issues when the gun was pushing more that 350 fps. In a stock gun, yes, the 11.1v will be problematic. Actually, it might cause the semi function to double/triple burst.

But in the space requirements of these guns, using a 7.4v 2000mAh is useless. I am running a 11.1v 1500mAh in my primairy AEG, with a 400 fps spring, and metal bushings. I have opened the mechbox this week, after over 5000 bbs. Nothing shows any signs of wear.

You have a lot more chance to do some damage in a RC vehicule where the power ratio is extremely high than in an airsoft gun.

For your information, it is not the shock of the fast acceleration that strips the grears in AEGs, it is usually the bad gear ratio used for the load (like a 450fps spring with high speed gears... no go).

In a stock AEG, the piston get stripped because the gears turn too fast for the piston to return to battery before the next cycle is started. This causes the sector gear to ram at the first teeth of the piston with full speed, while the piston is almost at it's maximum forward speed. It is the colision between the two that strip the grears.

It is the same thing when looking at a monster truck, for exemple an HPI Savage or Traxxas Revo. The soft nylon/delrin spur gear get stripped because the user is keeping trottle on while in the air. This cause the whole system to accelerate and when the wheel touch the ground, they all lock at the same time. That causes a shock.

It's always the weaker link that breaks.

AND

It is normal for an Echo1 piston to strip. VERY cheap nylon, sometimes even plastic are used in the fabrication of these, and the tolerences are totally random. I saw two Echo1 piston, out of 2 brand new rifles with a total teeth leght over 2mm in difference. Ask Classic Army owners what that little difference does.

Finally, my LiPo endures a lot less hits and pain when in my AEG than it would in any of my RC truck, cars or planes. It is always encased in a plastic/ABS/metal cover. I don't know if you crashed a planed yet, but I did. And the battery/motor/esc went sliding on the landing strip for a good 15'. I never saw that happen to an airsoft battery.

LiPo are not for newbies. Yes they are more fragile and require a lot more care than regular NiCd or NiMh batteries. But if you use them properly, you will get a lot more from them than an explosion.

Check the videos on YouTube. ALL of them are caused by false charging or damaged packs or faulty usage. I already wrote a thread about that. There was a 200+ list of exploding LiPo events. ALL of them where evitable.

Basic rules:

Don't over discharge (this includes discharging too fast).
Don't use or charge a damaged pack.
Don't stab yourself in the eye.

Anybody that is a bit sane should not have problems with LiPo if they follow the specs and care instructions of the maker of the packs.

[Slick]

Seems like everyone in Airsoft is using the 11.1 lipos. Theres no need to be afraid of the 7.4s. On a full charge they actualy charge up to 8.4v anyways and give an already fast rate of fire. I use a 7.4v Zippy with with a trigger master and so far have been really impressed. Last game I played I think I put about 1200 rounds through my gun at 400fps and the battery drained down to only 7.7v.

[arcanuck]

Originally Posted by Kos-Mos

Just a quick question.

How long have you been playing airsoft.

I have an extensive background in R/C, and I can tell you that these are two different worlds.

All my 7.4v I tried had overheat and poor performance issues when the gun was pushing more that 350 fps. In a stock gun, yes, the 11.1v will be problematic. Actually, it might cause the semi function to double/triple burst..

I have an extensive background in engineering. The primary fundamentals are the same. The overheating is caused by too low of a load resistance for the battery's discharge rate as I mentioned in my first post.

Originally Posted by Kos-Mos

You have a lot more chance to do some damage in a RC vehicule where the power ratio is extremely high than in an airsoft gun...

Ok... subjective

Originally Posted by Kos-Mos

For your information, it is not the shock of the fast acceleration that strips the grears in AEGs, it is usually the bad gear ratio used for the load (like a 450fps spring with high speed gears... no go).

In a stock AEG, the piston get stripped because the gears turn too fast for the piston to return to battery before the next cycle is started. This causes the sector gear to ram at the first teeth of the piston with full speed, while the piston is almost at it's maximum forward speed. It is the colision between the two that strip the grears..

By definition that is shockload, as I mentioned in my first post.

Sir, I don't want to be rude...but...lol.

[808]

Originally Posted by arcanuck

Sir, I don't want to be rude...but...lol.

Priceless.

If I sig'd people, that would be in there.

[ThunderCactus]

Originally Posted by Dusti69

i dont like my 11.1v lipo. ill only use it in one gun and only in semi. and to correct a guns firing when it stops and does the clicking thing and a burst on full auto doesnt fix it

its just way way too much power that you dont need most of all of the time and i dont need my gearboxes/parts wearing out any faster. i already stripped all the teeth off of an echo 1's piston from about 3 short bursts on full auto and had to buy a new piston

Actually, with a trigger master unit you can reduce the voltage going to your motor to reduce rate of fire. And it has soft start and active motor braking built in. Soft starting drastically reduces the shock on your piston.


I never even looked at LiPo batteries before getting a trigger master, now I'm seriously looking into switching over. But I'd say the use of a trigger master is HIGHLY recommended when using LiPos
It's even compatible with overdischarge protection boards made by dragonwolf.

Theres also this neat little thingy:
http://www.airsoftpost.com/intellect...r-p-30727.html

And to give you a better idea of sizing
http://www.airsoftpost.com/111v-1000...e-p-31118.html
Right now I use the King Arms AN/PEQ-15 with custom 9.6v 1500mah NIMH batteries

[MultipleParadox]

Necro'ing:

I recently installed an Ascu2 in my M4 and decided it was time to go Lipo at the same occasion, hating my crane-stock/battery combo with a passion.

I bought two "Buffer Tube" lipo from Airsoft Depot (11.1v, 1100mAh, 15C, Hotpower) and a Lipro B6 charger.

Charged them with the charger and everything looked good. One left in the case after discharged, the other in the AEG (plugged abd charged).

I think (of memory serves) I charged them at a 0.6 Amp rate. Then again I'm not sure, MAYBY it was 1amp (not more for sure)

Yesterday I try my M4 to notice that both batteries were drained. Didn't give a thought or noticed anything (didn't care to look at them)

Today i decide to charge the batts, and one of them was making the charger alert for "Low voltage", and obviously didn't start to charge. Lo and behold, the battery swelled, the other is perfectly fine.

I can't tell if the swelled battery was the one left plugged in the AEG or not.

I guess that battery is done for right?
Could it have been deffect or is it me that didn't take good care enough, despite the fact that both were treated pracrically the same way? Should I try and ask Huang an exchange or something?

Any advices is welcome

Thanks in advance

[ThunderCactus]

The one that swelled is the one you left plugged in. It's not a defect, you overdischarged it, then tried to charge it, and it swelled.

1) Don't discharge LiPo batts with your charger if you're doing that, they don't need it
2) Don't ever leave any battery plugged into a gun with an SW-COMP. They drain a small amount of power even when you're not using the gun, so if you leave a LiPo plugged in, it's guaranteed to over-discharge

[MultipleParadox]

Good to know!
I don't think this as been "advertised" anywhere, has it been?

But then again I thought the Ascu was supposed to cut off the power in case of overdischarge? I guess it doesn't apply in that case then...

Not sure about what you mean on point #1?

Thanks for the heads up