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KWA SR7 Battery Question


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#1 souljacker360

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Posted 07 June 2014 - 11:37 AM

Hi guys I'm new to the forums and I just signed up.  I have a question regarding LiPo batteries compatibility with the KWA SR7.  I've done research on my own having looked on Google and seeing some related topics to the KWA SR7.  I just want to ask to clarify my questions because I'm not entirely sure and batteries can be pretty overwhelming to a first time KWA buyer.  I've found a battery online along with a charger that in my opinion should seem to work fine with the SR7 and I will link it below, if you guys have any suggestions or comments please let me know and maybe even provide me a link that would be gladly appreciated.  I also want to add a MOSFET system to my SR7, Airsoft GI offers an upgrade for this guy for $20.  Are there any issues with the connectors between the SR7, MOSFET system, and the battery I need to worry about, for example do I need to be a connector adapter? Thank you

LiPo Battery-http://www.hobbyking...Warehouse_.html

LiPo Battery Charger-http://www.hobbyking...Warehouse_.html

MOSFET System-http://www.airsoftgi...oducts_id=16461

#2 tales

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Posted 07 June 2014 - 01:09 PM

Hi,

Battery: 2.0mAh Out of stock i picked a few up for $20 shipped on ebay, around the same price as Hobby King. HK might have Lower mAh in stock.
http://www.hobbyking...RSOFT_Pack.html

The charger you posted is DC i don't think it has an adapter. There are better choices, i have a few different lipo chargers.

Mosfet: thats a burst it can be hardwired, that requires opening the gearbox, there is a DIY link in the forums for one with active breaking, It works!

Edited by tales, 07 June 2014 - 03:49 PM.


#3 souljacker360

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Posted 08 June 2014 - 02:54 PM

Thank you so much for your reply,  I now have confidence in purchasing the right batteries lol.  It can be very confusing especially to buy a battery for a gun.  Any chargers you recommended that aren't too pricey?

Edited by souljacker360, 08 June 2014 - 02:58 PM.


#4 Chuck S

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Posted 09 June 2014 - 02:21 AM

Addressing these in order:

1.  A 7.4v LiPO will give about the same performance as a 8.4v NIMH battery because the LiPO is capable of dumping current faster.  For a performance increase -- trigger response and cyclic rate -- an 11.1v LiPO is what is used.

2.  I doubt a $5 LiPO battery charger has a way to equalize the cells in the battery.  There's a reason the preferred chargers are $50.  :)

3.  MOSFET is a metal–oxide–semiconductor field-effect transistor.  As commonly used in airsoft triggers it's an electronic relay.  The trigger contacts only handle a minute amount of current, just enough to trigger the relay which handles the heavy current.  Since the relay is solid state there are no sparks or wear on the trigger contacts.  To get the relay effect the device must be connected inside the gearbox, a pretty consequential task fraught with risks, lost parts, misassembly, etc.

The King Kong device Evike is selling can be wired into the gearbox as a MOSFET relay or just connected between the battery and gun.  In this mode it's a burst controller and factory set to 3-round burst.  I like the device when wired this way.  But wired this way it does not protect the trigger contacts.  KWA trigger contacts seen to need little or no protection from recent posts here.

Recommendations:

1.  Find an 11.1v LiPO that fits your gun and buy two (2).
2.  Get a good charger that runs off 120v AC.  Some use a wall wart and can often be connected to a car battery, others have the transformer internally.  The "TB6AC" type chargers are close to universal and will charge LiPOs and your other batteries easily.  The circuit boards and menus on these chargers are all very similar.
3.  I like the King Kong burst device and you can just plug it in and shoot with it.  If you get daring and your airsoft "armorer" skills eventually get good enough it can be wired into the gearbox to protect the trigger contacts and still retain the burst function.  But note the post earlier this weekend of the installation problems of these devices.  I readily admit I have not opened an AEG gearbox and currently have no intention to do so!  

If you're buying batteries and chargers from the Orient it can take several weeks.  The "US Warehouse" notation cuts the time to a week since the stuff is already in CONUS.

-- Chuck

Edited by Chuck S, 09 June 2014 - 02:24 AM.


#5 souljacker360

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Posted 09 June 2014 - 06:02 AM

Wow very informative reply thanks I really appreciate it.  What mAh would you recommend? Because I know that over 20A continuous is considered out of spec.

#6 Desert Punk

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Posted 09 June 2014 - 06:18 AM

I use the turnigy 7.4v 1400mah batteries and have had no problems with them. However they will not fit in the KWA crane stock. But they do fit nicely in the buffer tube. As for the charger the cheapest one that i would use is this one. http://www.evike.com...cts/41649/  And don't get the Burst Wizard King Kong Super 2 Mosfet I have one and hate it with a passion. If you want a good mosfet look at GATE line of mosfets.

#7 uriahskates

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Posted 09 June 2014 - 12:30 PM

http://www.hobbyking...RSOFT_Pack.html

This battery will fit the SR7 Crane Stock. These are the same ones I use. Make sure to get these batteries specifically because the 1400 mAh and the 2000 mAh ones will not fit I believe. You can put two of the cells in one of the circular slots and the other cell in the other circular slot. As a word of advice, get two or three because these will not last very long, maybe 4 hours at most.

#8 souljacker360

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Posted 09 June 2014 - 12:50 PM

I think I'll settle on the batteries uriahskates recommended since he has the same gun as well. As for the MOSFET I'll probably pass on it for now since muy knowledge of gun internals is vague. Thank you to everyone that answered my questions.

Edited by souljacker360, 09 June 2014 - 12:54 PM.


#9 uriahskates

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Posted 09 June 2014 - 01:38 PM

Not sure if you can see the batteries due to all the wiring..but..here you go. :lol:

Attached File  photo (1).JPG   112.86K   27 downloads

#10 Pyro_Buster

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Posted 09 June 2014 - 01:55 PM

I use a custom built battery from eliteairsoftbatteries.com. He makes one specifically for KWA crane stocks. 2200 mAh and it lasts me all day. Plus he'll fix your battery for you whenever. Even if it's outside the one year warranty he gives you. Great guy and I highly recommend.

#11 tales

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Posted 09 June 2014 - 02:02 PM

FWIW, i have an SR7 and a 11.1v 2.0 mah does fit.

This one
Posted Image

IMO, the 7.4 with a high RPM motor will give a ROF up there with a KWA stock motor and a 11.1V lipo.
Without sending another 3.7V through your gun, something to think about.

As for the charger, in airsoft there called smart chargers, RC there known as peak chargers,  chargers aren't smart.
They detect when the battery back peaks in voltage and starts loosing voltage from over charging, and stops charging. The sooner it stops when over charging the better for the battery. Its a $10 airsoft battery not a $90 RC battery


I have chargers that top $100 and they shut off airsoft batteries as soon as the voltage starts to drop. Pack is room temperature not too warm
Airsoft chargers i noticed will continue to charge a battery after my LRP or Traxxas charger stopped charging them.

Leading to a warm - very warm battery, when over charged it lowers the voltage.

Im not saying buy $130 charger for a $10 airsoft lipo.
I think you will have to spent at least $20+ for a clone airsoft charger, JMO.

Good Luck!

Edited by tales, 09 June 2014 - 02:45 PM.


#12 souljacker360

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Posted 09 June 2014 - 03:50 PM

@uriahskates I can see the batteries, 2 on one side and the 1 on the other side.  I'm assuming that your batteries are identical to @tales batteries the only difference I noticed was that one was 1200mah and the other was 2000mah.  Now I know that the more mah the longer it will last on a full charge.  I was looking at the Tenergy TB6AC that one @Chuck S mentioned and I saw a video review of it on YouTube.  The charger really seems good and I might just get that one, and correct me if I'm wrong the TB6AC will work with any battery no matter what brand.

#13 tales

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Posted 09 June 2014 - 04:00 PM

There the same battery as stated one lasts longer then the other
2.0 lasts my son a whole weekend when he go to the Hamptons
That's where he uses 11.1s the most
Locally it's CQB and 7.4s

One cell in each compartment and one cell in the buffer tube
Still room for a small mosfet in the tube,  if that's your goal

I can post a pic later if you like, there on the forums already :)

Edited by tales, 09 June 2014 - 04:01 PM.


#14 tales

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Posted 09 June 2014 - 04:12 PM

Oh, forgot to mention you have to remove and rewire that calamity of a fuse harness that's in the tube
Hockey time :)

#15 tales

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Posted 09 June 2014 - 04:17 PM

Brick
http://m.youtube.com...h?v=MRakTILZOf0

#16 souljacker360

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Posted 09 June 2014 - 04:17 PM

@tales Wait the rewiring, does that having to do with the batteries or the MOSFET?  If it's the MOSFET I've decided to just stick with the good 'ole finger lol.

#17 tales

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Posted 09 June 2014 - 05:11 PM

End of 1st Rangers give up a goal with 0.8 seconds left :mad:

The gun, i think it has that coiled wire in the buffer tube. Are you using the KK as a mosfet or burst?
I remove the fuse harness & pistol grip on KWAs when there new. I always forget to post that, sorry!

The gearbox wiring looks like this, three on the left go to the mosfet
Posted Image

Thats a GB for a different KWA, his 11.1 is in a K4 RIS with a ported piston Full metal rack, POM head and KWA M130 spring no Fet.
Using this motor he gets a high ROF
http://www.airsoftgi...oducts_id=16024

This is a fet left in one gun Pico AB fits in the tube with battery
Posted Image
Posted Image
Posted Image

HTH

#18 gcw360

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Posted 09 June 2014 - 05:38 PM

Battery charger - Thunder AC6: http://www.hobbypart...ac6smbachw.html

I love mine and they have been used by KWA.

#19 souljacker360

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Posted 09 June 2014 - 06:15 PM

@tales Sorry you've lost me man, is all this rewiring for the MOSFET system?  I'm not very knowledgeable in airsoft internals so all that information looks like foreign language to me.  I've decided just to run stock on the SR7 without a MOSFET system. Simply just put the nunchuck battery in the crane stock and pull the trigger.

@gcw360 Thanks man I will consider that since it is almost if not identical to the one by Tenergy and costs less as well.

Edited by souljacker360, 09 June 2014 - 06:15 PM.


#20 tales

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Posted 09 June 2014 - 06:49 PM

Sorry English is my first language
That is a mosfet.
The mosfet you posted can work as a mosfet
Over riding the trigger contact & or a burst
What do you plan on using the mosfet for
Just burst?




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