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Sr7 Li-Po Choices


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#21 gcw360

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Posted 26 December 2013 - 02:39 PM

View PostJesse Hammil, on 26 December 2013 - 01:35 PM, said:

Am I blind? I don't see the voltage on that.
3 cells = 11.1 volts.  2 cells = 7.4

#22 gcw360

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Posted 26 December 2013 - 02:42 PM

View PostJesse Hammil, on 18 December 2013 - 03:49 PM, said:

I called our local shop, and they have a couple that fit. It's both are 11.1v 20c 1200mah.  That seems like it's out of spec. I thougt spec was 20A and that battery is 24A if I'm doing math correctly. Am I wrong on what is "in spec"?
You are typically fine with 24 amp batteries.  The arching that may occur shouldn't be much of an issue.  I've used 1200 mAh 20C's for years with no adverse effect though I typically use 15C 1200-1400mAh batteries now because the performance offered is very good and they are cheap.

#23 Jesse Hammil

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Posted 26 December 2013 - 03:40 PM

View Postgcw360, on 26 December 2013 - 02:42 PM, said:

You are typically fine with 24 amp batteries.  The arching that may occur shouldn't be much of an issue.  I've used 1200 mAh 20C's for years with no adverse effect though I typically use 15C 1200-1400mAh batteries now because the performance offered is very good and they are cheap.

I must be more tired than I think.  I have been unable to turn up a 15c 1400mah battery :/

Edited by Jesse Hammil, 26 December 2013 - 03:44 PM.


#24 gcw360

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Posted 26 December 2013 - 07:11 PM

See here: http://www.hobbyking...idProduct=24206

I would use this one though: http://www.hobbyking...idProduct=24203

It's a better fit in a KWA crane stock.

#25 Jesse Hammil

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Posted 26 December 2013 - 07:33 PM

Wow. Those are cheap! Thanks!

#26 gcw360

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Posted 26 December 2013 - 07:55 PM

View PostJesse Hammil, on 26 December 2013 - 07:33 PM, said:

Wow. Those are cheap! Thanks!
My pleasure.

#27 Everything_airsoft

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Posted 25 January 2014 - 09:32 PM

View PostHitman07, on 09 August 2011 - 09:15 AM, said:

Get the Tenergy 11.1v 1600mAh 20c. I have it for my G36 and I take it apart on a monthly basis and everytime the gears look great. I have had the gun since Dec. 2010 and have put close to 100k rounds through it.
Hey one question about how long will this battery last on a full charge?

#28 Larry

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Posted 26 January 2014 - 05:47 AM

Every gun runs thru batteries at different rates (upgraded gun, temp, charger, battery maker), 1200 shots give or take 200 or so. . Dont run your Li-Po down!! If the gun doesnt fire or seems slow, stop and put another one in. Try not to discharge them all the way (not good), even if you think it might be a non battery issue. Always test your gun with a known good battery.

Edited by Larry, 26 January 2014 - 05:58 AM.


#29 Chuck S

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Posted 26 January 2014 - 06:34 AM

LiPO battery should not be discharged below 3.2v per cell or it will be damaged.  Perhaps not fatally but deep discharge will eventually kill the battery.  That's 9.6v or 6.4v depending on the battery used.  Problem is it's impossible to measure the voltage of the battery in the gun!  I have Burst Wizards in both my KM4 and RM4.  Mainly for the 3-round burst option and secondarily for the battery voltage protection these have.  The device "beeps" when the battery voltage drops to 9.4v or 6.8v under load and cuts the power when the no-load voltage is below the critical voltage.  The beeps give me a chance to replace the battery before the gun stops shooting.

The C-rating of the battery is the maximum continuous load the battery can be subjected to safely.  Got nothing to do with the gun, it's a battery safety item.  The popular BOE 1400 mAh 15C 11.1v LiPO battery can be safely subjected to a continuous draw of 21 amps  (1400/1000 x 15 = 21).  As long as your gun is drawing less than 20 amps the C-rating is irrelevant and if it's drawing more than 21 amps this battery can be damaged.  The fuze in KWA guns is 20 amps. High amperage draw can electrically wear your trigger contacts but the battery C-rating has nothing to do with this.

-- Chuck

#30 Larry

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Posted 26 January 2014 - 07:22 AM

I only replied to his ? about how long the battery will last. The same battery will last longer in some guns vs others. Even in two different sr7s. Shimming, motor adj, ect. The battery changes the performance of the gun, and the gun changes the perferformance of the battery. Key word being performance. Battery spec stays the same, output wise.

Edited by Larry, 26 January 2014 - 07:56 AM.


#31 gcw360

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Posted 26 January 2014 - 08:42 AM

View PostEverything_airsoft, on 25 January 2014 - 09:32 PM, said:

Hey one question about how long will this battery last on a full charge?
A 1600 mAh Lipo in a stock KWA should yield between 1600-2400 shots.

#32 Chuck S

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Posted 27 January 2014 - 03:53 AM

Battery life depends on the amp hour rating (milliamp hour rating in this case) of the battery and the amperage the motor draws for what amount of time.  In the same gun a heavier spring will require the motor to work harder and pull more amps.  Internal friction in the gear box is another factor-- cold weather thickens the grease inside and the motor works harder.  Connectors, etc. all factor and all guns are different.  Best bet is to have a spare fully charged battery and see how long your battery lasts.  A 1600 mAh battery will last longer than one rated at 1400 mAh.

Batteries are chemistry and tend to have a recovery period.  But when the gun slows down it's time for a battery change.  Note the cautions about discharging a LiPO too far.  

-- Chuck

#33 gcw360

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Posted 29 January 2014 - 03:27 PM

View PostChuck S, on 27 January 2014 - 03:53 AM, said:

Battery life depends on the amp hour rating (milliamp hour rating in this case) of the battery and the amperage the motor draws for what amount of time.  In the same gun a heavier spring will require the motor to work harder and pull more amps.  Internal friction in the gear box is another factor-- cold weather thickens the grease inside and the motor works harder.  Connectors, etc. all factor and all guns are different.  Best bet is to have a spare fully charged battery and see how long your battery lasts.  A 1600 mAh battery will last longer than one rated at 1400 mAh.

Batteries are chemistry and tend to have a recovery period.  But when the gun slows down it's time for a battery change.  Note the cautions about discharging a LiPO too far.  

-- Chuck
All true.




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