11.1v Li-po + No Mosfet / Why You Can Get Away With It.

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vanevery
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11.1v Li-po + No Mosfet / Why You Can Get Away With It.

Post by vanevery » Sat Feb 02, 2013 1:32 am

This is a trigger contact from a JG M4-S-System(Bottom of page).
The pictures are from my cell phone so the quality is not good.

This gun has been my back-up for the last two years.
I have used it in a handful of games as my primary but most of the rounds thru it have come thru testing at the range of inner barrels, bucking and nub combos, and endless Flat-hop combinations.
I would estimate this gun has had around 50,000 rounds thru it.
I estimate that 80% of my shots have been semi-auto and 20% full-auto with 1 second max duration trigger pulls.

There have been two batteries used on this gun.
11.1v / 1100mah / 15C used 99% of the time
10.8v / 1600 mah / 12C PEQ battery used 1% of the time.

After cleaning this contact with rubbing alcohol, there was not a mark on it.
Other than the typical impression made on the forward Bend on the Selector Plate side of the Contact that occurs on all trigger contacts, the metal Contact looks brand new. The Female Contacts look just as good. These Contacts could easily go for a minimum of 200,000 more rounds in the same set-up.

My KWA Trigger Contacts look pretty good as well after around the same amount of rounds, but I use higher amps and C-rated 11.1v Li-po batteries in them (up to 2500mah /30C) so they do not look this good.

So, does this mean Stock guns with Stock wiring are Li-po ready? No!
It just means that if you execute trigger control on full-auto and use semi-auto the majority of the time, you can get away with using low amp / low C-rated 11.1v Li-po batteries and enjoy a lot of the benefits that Li-po batteries offer: Cost, Charge Duration, Trigger response, ROF, etc.....

Keep this in mind:
If the mechanical gearbox components are not properly tuned for 11.1v Li-po batteries and if the components themselves are not good quality, then using 11.1v Li-po's is the wrong choice of battery, even if your electrical system can handle it.

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Re: 11.1v Li-po + No Mosfet / Why You Can Get Away With It.

Post by SteevoLS » Sat Feb 02, 2013 9:52 am

Something you touched on but didn't really go into depth about:

When it is recommended that you use a MOSFET in conjunction with a LiPo, it is generally assumed that you are using a high output battery. The PEQ-sized 11.1v batteries that you get in the Vanaras (and similar) PEQ boxes are pretty anemic. That 11.1v 15c battery is probably on par with a hefty 9.6v battery, and is unlikely to cause any real damage to trigger contacts. Put a 40c 11.1v brick in the stock and you would see a much different set of trigger contacts after two years.

Now, that having been said: My standard M.O. is to leave the wiring in a gun stock and run it on a large battery. I haven't used anything under a 40c 11.1v in years. Eventually my trigger does indeed cease to function properly, at which point I rip everything out and install new contacts/MOSFET/low resistance wiring.

Big battery + no MOSFET + 50k rounds:

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vanevery
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Re: 11.1v Li-po + No Mosfet / Why You Can Get Away With It.

Post by vanevery » Sat Feb 02, 2013 7:46 pm

SteevoLS wrote:Something you touched on but didn't really go into depth about:

When it is recommended that you use a MOSFET in conjunction with a LiPo, it is generally assumed that you are using a high output battery. The PEQ-sized 11.1v batteries that you get in the Vanaras (and similar) PEQ boxes are pretty anemic. That 11.1v 15c battery is probably on par with a hefty 9.6v battery, and is unlikely to cause any real damage to trigger contacts. Put a 40c 11.1v brick in the stock and you would see a much different set of trigger contacts after two years.

Now, that having been said: My standard M.O. is to leave the wiring in a gun stock and run it on a large battery. I haven't used anything under a 40c 11.1v in years. Eventually my trigger does indeed cease to function properly, at which point I rip everything out and install new contacts/MOSFET/low resistance wiring.
Big battery + no MOSFET + 50k rounds:
You are exactly right about low amp batteries being anemic and on par with 9.6v / high amp batteries.
BTW: Just so we are clear, I am in no way advocating not installing a mosfet.
The point I was making is that one can get away with using a 11.1v Li-po for a period of time and get the benefits that Li-po batteries offer.
I maintenance my guns often and am an endless tinkerer.
So to me, getting good use out of the stock wiring harness and trigger contacts with a 11.1v Li-po is a cost effective way yo get good use out of 50.000 - 150,000 rounds in either an all stock set-up or upgraded / properly tuned set-up.

I will add the point that in my KWA's, I use higher amp 11.1v Li-po batteries and higher C-ratings.
Up to 2500mah and 30C with stock wiring. Not 40C juice, but far from anemic.
I always change out those trigger contacts every 50,000 rounds so I can essentially go forever using the 2500mah / 30C Li-po batteries without a mosfet and no worries of electrical failure.

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Re: 11.1v Li-po + No Mosfet / Why You Can Get Away With It.

Post by Dominum » Mon Feb 04, 2013 4:19 pm

Just one thing to add:

Shooting 5k rnds on semi will burn your contacts down faster than shooting 5k rnds on full auto. Why? The electrons will only arc right before and right after the contacts physically touch. So it is actually better for your contacts to use less semi auto and more bursts on auto. Obviously what is even better is to use a MOSFET, or a lower discharge battery.
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