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LiPo Battery Warning!!!


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#101 Guest_NumenoreanBlood_*

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Posted 05 April 2010 - 10:22 AM

View PostVamp2269, on 05 April 2010 - 09:45 AM, said:

how do you know that do you own a chrono with that can measure fire rate.
Working on getting one, but I recorded an audio track of my gun firing, then used Audacity to see how many times it fired in an one second block by looking for the sound of the firing cycle.

#102 Vamp2269

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Posted 05 April 2010 - 10:43 AM

that doesent seem very accurate

#103 Guest_NumenoreanBlood_*

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Posted 05 April 2010 - 10:53 AM

View PostVamp2269, on 05 April 2010 - 10:43 AM, said:

that doesent seem very accurate
Why not?  Audacity is a great program, used by professionals and all, not to mention that the mic that I recorded it with is not too shabby, either.  The audio of each shot was easy to distinguish from each other, and I was able to bring up a graph of the noise peaks, allowing me to just count them.  Not too hard, and actually surprisingly accurate.

#104 Gorilla

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Posted 05 April 2010 - 01:52 PM

View PostVamp2269, on 05 April 2010 - 10:43 AM, said:

that doesent seem very accurate

Actually, that method is far more accurate than a chronograph (just more equipment intensive). It also allows you to analyze differences in fire rate (rises or drops) during a fire burst.

G.

#105 chedeath

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Posted 05 April 2010 - 02:18 PM

View PostVamp2269, on 05 April 2010 - 09:45 AM, said:

how do you know that do you own a chrono with that can measure fire rate.

yes, most do.

#106 Guest_allizard_*

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Posted 05 April 2010 - 03:23 PM

View PostNumenoreanBlood, on 05 April 2010 - 09:33 AM, said:

Then how come I'm using a 2200mAh, 25C continuous (55A), 35C burst (77A)  11.1v LiPo, and I'm still only getting about 19-20 bb's per second, which is exactly what my gun is rated at with a 11.1v, 1600mAh, 15A LiPo?  By what you're saying, shouldn't I be seeing something higher?  Also, I still get off well over 3,000 BB's off with one charge, so I don't think that it is draining very fast, as your example suggests that it would.

Those numbers don't add up.  You should be getting close to 25+ rps.   Are you sure the spec is REALLY what they claim to be?!   Did you get the result from a KWA gun or a different gun?

#107 KWAHK MAN

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Posted 05 April 2010 - 03:23 PM

View Postvic_man4, on 21 June 2008 - 12:23 PM, said:

If you want to increase ROF using a 9.4v battery, here are some suggestions:
1) get better wiring for the gun (this willl increase trigger response and make your battery operate more efficently and increase ROF)
2) Get a MOSFET (This can increase your ROF up to 30%) Click HERE to look at some amazing MOSFETS

This thread is getting off topic lol, lets get the subject back to LiPo
I dont like mosfets... break to easily then gun is out-of-commision  :thumbsdown: although when they work it is very nice :)

#108 Guest_NumenoreanBlood_*

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Posted 05 April 2010 - 03:55 PM

View Postallizard, on 05 April 2010 - 03:23 PM, said:

Those numbers don't add up.  You should be getting close to 25+ rps.   Are you sure the spec is REALLY what they claim to be?!   Did you get the result from a KWA gun or a different gun?
Actually, I just realized that the numbers that I posted weren't right, because I slowed it down and multiplied by the wrong number to make it per second.  My actual ROF ( I just re-tested it) is only about 16 BB per second  :thumbsdown: .  How it's that low, I'm not sure...  I've noticed that all reviews the KWA M16BR guns that were made around the time that mine was have the people saying that they chrono'd their gun's MUCH hotter (470fps compared to 420fps) than the one's reviewed that were made more recently.  Mine was chrono'd by ASGI before they shipped it to me, and it is among the higher FPS group.  That leads me to believe that, at least for a while, the guns were sent with stronger springs, which would explain the lower ROF.

To confirm that my ROF method works, I did the same with my brother's M11A1, and got about 29-30 bb's per second, which is exactly what it should be.  

To bring this back to batteries, I'm going to use my friends 11.1v LiPo (the 1600mAh, 15A standard airsoft battery) to do another test later tonight, and I'll post the results to confirm the effect of the mAh and Amp ratings on batteries once and for-all.

Edited by NumenoreanBlood, 05 April 2010 - 03:59 PM.


#109 Guest_NumenoreanBlood_*

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Posted 05 April 2010 - 04:12 PM

View Postallizard, on 05 April 2010 - 03:23 PM, said:

Those numbers don't add up.  You should be getting close to 25+ rps.   Are you sure the spec is REALLY what they claim to be?!   Did you get the result from a KWA gun or a different gun?
I just realized that I forgot to answer your questions  :whistle: .  Yes, I am sure that the battery was rated properly.  It was designed and made for RC helicopters, so it needs an impressive Amps rating.  The results that I got were from a KWA M16BR, with the only two customizations being a quad-rail RIS unit to replace the foregrip, and an EdGi 6.01mm tightbore.  The gun was made in the summer of 09, and purchased from AirsoftGi (they were out of stock, and I ordered right when they got a new shipment, so I know that it wasn't an older gun that had been sitting on a shelf for some time).

Edited by NumenoreanBlood, 05 April 2010 - 04:13 PM.


#110 ninemarker

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Posted 05 April 2010 - 04:23 PM

How to calculate the amp rating of a battery has been referenced but not actually put in this thread.
So here it is as just an FYI…


Battery Amp Rating
(C rating x mah)/1000 = continuous discharge amperage.

____________________________________________________________________

11.1V 1800mah 15C LiPo
15 (C rating) x 1800 (mah) = 27,000 / 1000  = 27Amp battery (continuous)

11.1V 1800mah 20C LiPo
20 x 1800 = 36000 / 1000 = 36 Amps

11.1V 2200mah 20C LiPo
(20 x 2200) / 1000 = 44 Amps

Another example…

11.1V 1800mah battery 10C
&
11.1V  900mah 20C battery

are both rated at 18Amps

#111 gabe940

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Posted 05 April 2010 - 04:43 PM

I used an 11.1v 5000Mah 20c LiPo battery is my G36c (the 2G) for over 20,000 rounds and I had no issues. The only problem that happened was that it was cycling so fast that on full auto the sector gear would catch the piston before it went all the way forward which caused some loss in range and shooting velocity. Fixed that problem with a stronger spring.

#112 chedeath

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Posted 05 April 2010 - 09:50 PM

View Postgabe940, on 05 April 2010 - 04:43 PM, said:

I used an 11.1v 5000Mah 20c LiPo battery is my G36c (the 2G) for over 20,000 rounds and I had no issues. The only problem that happened was that it was cycling so fast that on full auto the sector gear would catch the piston before it went all the way forward which caused some loss in range and shooting velocity. Fixed that problem with a stronger spring.

i have found a mosfet helps with that. than check contacts every now and again.

#113 !NFAMOUS

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Posted 09 April 2010 - 06:25 PM

View Postbusterlonghorn, on 03 April 2010 - 05:47 PM, said:

Yes the 11.1 will have more wear but that's the whole point of a kwa. it can take a 11.1 lipo with ease.
ok, so since the kwa can "handle the 11.1v with ease" how long is my 2gx gearbox gonna hold up on it?

#114 Jonas888

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Posted 10 April 2010 - 01:52 AM

Longer than any other GB's! Posted Image
What kind of answer do you expect really? "It will last for exactly 4 years, 13 days, 53 minutes and 33 seconds." ?
I don't think anybody can answer that, it all comes down to how you threat your gun I guess, maintenance, how long you hold you fire on full auto's/sprays etc.
Even then it's no formula like : 3-Second burst + maintenance every 5th month / 11.1V LiPo XXXXmAh  XXA XXC = 5 years
Think I made my point. : p

#115 Spiggy

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Posted 12 April 2010 - 01:25 PM

View Post!NFAMOUS, on 09 April 2010 - 06:25 PM, said:

ok, so since the kwa can "handle the 11.1v with ease" how long is my 2gx gearbox gonna hold up on it?
unofficially, I have no clue.  I have yet to break a gearbox in the fashion that normally destroys a gearbox.  There was rumors of a 2G gearbox breaking on another forum.  Turns out, that kid was a fraud and had severely abused the gearbox and stripped out the threading.   :rolleyes2: He had openly declared that he purposefully modified his gun and intended on defrauding us for a fix.  Genius.

As of current, anything that goes through the torture tester will break the motor in an hour of continuous firing.  And I mean CONTINUOUS.  The motor generally dies due to severe overheating. They'll get hot enough that you can't touch the pistol grip.  We don't use a battery for torture testing, we have special equipment that replicates batteries in different configurations as well as a continuous bb feeder that I rigged together.

#116 gcw360

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Posted 12 April 2010 - 03:57 PM

View PostSpiggy, on 12 April 2010 - 01:25 PM, said:

unofficially, I have no clue. I have yet to break a gearbox in the fashion that normally destroys a gearbox. There was rumors of a 2G gearbox breaking on another forum. Turns out, that kid was a fraud and had severely abused the gearbox and stripped out the threading. :rolleyes2: He had openly declared that he purposefully modified his gun and intended on defrauding us for a fix. Genius.

As of current, anything that goes through the torture tester will break the motor in an hour of continuous firing. And I mean CONTINUOUS. The motor generally dies due to severe overheating. They'll get hot enough that you can't touch the pistol grip. We don't use a battery for torture testing, we have special equipment that replicates batteries in different configurations as well as a continuous bb feeder that I rigged together.
Let me spare some of you the calculation: 20RPS x 60 sec x 60 min = 72,000 rounds/hr.:gun:

#117 Spiggy

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Posted 12 April 2010 - 04:26 PM

^ it depends on the output we use.  For the most part, things die fairly quick when we get past the 12v line. That applies to all the sorts of brands that I've pitted against my torture tester.  Physically, our gearbox shell holds up the best as far as beat-up factor goes.

#118 bludragon071889

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Posted 13 April 2010 - 12:02 AM

View Postninemarker, on 05 April 2010 - 04:23 PM, said:

How to calculate the amp rating of a battery has been referenced but not actually put in this thread.
So here it is as just an FYI…


Battery Amp Rating
(C rating x mah)/1000 = continuous discharge amperage.

____________________________________________________________________

11.1V 1800mah 15C LiPo
15 (C rating) x 1800 (mah) = 27,000 / 1000  = 27Amp battery (continuous)

11.1V 1800mah 20C LiPo
20 x 1800 = 36000 / 1000 = 36 Amps

11.1V 2200mah 20C LiPo
(20 x 2200) / 1000 = 44 Amps

Another example…

11.1V 1800mah battery 10C
&
11.1V  900mah 20C battery

are both rated at 18Amps


The math make sense but isn't that for when you short the battery across it's terminals? As in the MAX amperage that the battery can obtain?

In electronic circuits, there is something called the Thévenin's Equivalent Resistance; essentially the internal resistance of the gun when you assume that any internal dropping of voltage are negligible. That allows us to calculate the voltage and amperage of the battery using the simple V=IR formula. Does anyone? (looking at the KWA Employees) have that Ressitance.

I may be completely wrong in using that value or the internal resistance is so tiny, the gun may just run on the MAX amperage.

Also what is wrong exactly with running a higher amperage? Motors run on Volts not Amps like LED's so they should be fine regardless of the Amperage given to them. Again bringing the internal resistance of the motor into the fold...

#119 Guest_NumenoreanBlood_*

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Posted 13 April 2010 - 05:16 PM

View Postbludragon071889, on 13 April 2010 - 12:02 AM, said:

The math make sense but isn't that for when you short the battery across it's terminals? As in the MAX amperage that the battery can obtain?

In electronic circuits, there is something called the Thévenin's Equivalent Resistance; essentially the internal resistance of the gun when you assume that any internal dropping of voltage are negligible. That allows us to calculate the voltage and amperage of the battery using the simple V=IR formula. Does anyone? (looking at the KWA Employees) have that Ressitance.

I may be completely wrong in using that value or the internal resistance is so tiny, the gun may just run on the MAX amperage.

Also what is wrong exactly with running a higher amperage? Motors run on Volts not Amps like LED's so they should be fine regardless of the Amperage given to them. Again bringing the internal resistance of the motor into the fold...

I don't know if this method gives an accurate measurement of the motor's resistance, but putting one prong of a multimeter onto each terminal of the battery connector, then pulling the trigger while in full-auto to hold the circuit open, I got about 10 ohms.  The multimeter that I have is a $3 POS that does not take the resistance of the leads out of the final numbers, so I touched them together to find their resistance.  Can you guess what I got?  About 10 ohms.  So, the motor should have been under one ohm of resistance.  Another way of seeing this is that I have *only* once popped the 15A fuse in my gun with a 11.1V LiPo.  That current draw from that battery would equal roughly .75 Ohms, and I bet that the motor wasn't even quite to a full stall.

Bringing up the fuse...  I use fast-acting 15A fuses in my gun.  My battery (and just about any battery you'll use in an airsoft gun) are rated higher than 15A.  If increasing the Amps rating on the battery mattered, then shouldn't one expect that the Amps rating of the battery is the limiting factor that decides the current draw?  Going along that thought process, my 75A burst, 55A constant battery should pull AT LEAST more than 15A.  But it doesn't.  My fuses would be popping like crazy if it was, but they aren't.  Why is that?  Because the voltage, and the voltage only, is the only factor that the battery has on the motor's current draw (just make sure that the battery's amperage rating exceeds the current, or it may light on fire, as it will still draw the higher current, but the battery's internals can't handle it).

Edited by NumenoreanBlood, 13 April 2010 - 05:28 PM.


#120 diehard

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Posted 20 April 2010 - 05:19 PM

its a good thing i'm only getting a Matrix 1500mah lipo




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