Running 22.2V
 

Hey guys,

So for awhile now I've been pondering the thought of running a gun off (2) 11.1V lipos that I have sitting around. They both fit into the crane stock quite nicely, and it seems possible.. but is it worth it?

The gun is equipped with a MERF 3.2, a Lonex A2, 14AWG wiring, and a whack of other stuff. There's not a stock part left on it.
I would have to take the MERF out, as that can't handle anything above 14.8V But what about the rest of the system? What would a motor do when connected to that type of current/amps?

I'm thinking it's going to crash and burn, literally.

Has anyone tried this? What results would be expected?

Thanks

Expect a Lonex motor to get hot and burn the brushes quickly. Considering your gun doesn't feed properly at 30 RPS it may jam and strip your piston. Running a DSG on 14.8V is not uncommon, and I've heard of a guy running a 18.5 in a high power + high speed gun, so 22.2 would probably work if you do things correctly.

Maybe you should learn the basics of electronics before you attempt this. To get 22.2 V out of two 11.1 V packs you have to wire them in series. This will not increase current (amperage). I remember learning this in grade 6.

22.2 would kill most electronics, not to mention high voltage is very bad for your motor. And you wouldn't be running at 22.2v, you'd be running at 25.2v.
You'd gain some ROF from wiring them in parallel due to lower resistance though.

Oh you're so funny. And you don't know the basis of leaving electronics in the cold. I also hear you like to fill buffer tubes with cement. Feeding problems are all fixed in the gun, it was a $3 delayer that failed. This isn't going in my M4 either, it's going in a different project.

I managed to trade a guy for a Chrono too, getting that tomorrow.
And I wouldn't want you being anywhere close to an "apprentice" of mine, as based off your earlier thread. I don't think you have nearly the skill of what my employees do, and don't deserve near what I pay them.

But I digress.

I'm aware I would have to wire them in series.. I have the Y-splitter from my buddies RC car. But yes, I have heard of guys running 18.5s on DSGs, that's what got me thinking of it. I'm debating seeing if I can get lower amperage batteries, so that it wouldn't be as much of a load on the gun.

How would it be 25.2v? Even if it were a 6S Lipo, that would only be 22.2V, wouldn't it?

Fully charged 3S lipos are at 12.6V.

RIGHT, thanks! That slipped my mind. I've been addicted to GBBRs lately, I forgot about that.

Somebody's mud. Very mud.

I don't recommend anything above 14.8V. I'm led to believe that above those voltages, the potential difference will be far too great to be sustained. (namely if you remove the FET, your trigger plates and/or wiring will overheat. After all, you're going to be passing over 400watts of power through some maximum 14awg wire)

You're definitely welcome to try it and let us know. I'm actually fairly curious but understand that it's beyond the realm of practicality.

6s lipo would probably fry the fet I'd imagine.. or at least the supporting components of the fet on the pcb itself. Might even melt the traces off the pcb.

If the power makes it through, then your gears will probably destruct the piston or themselves... as they'll be traveling faster than the system can cycle.

Mechanically I suppose you could get it to function... practically speaking, feeding will be the issue. I'm reasonably sure people have cracked the >100rps cyclical rate mark but feeding remains somewhere in the 80s.

IF you do this... Film it... Outside

Dont forget the fire extinguisher.

are you running the batteries in parallel or in series? In series you are adding voltages. In parallel you are "adding" the Mah values together. Its quite common for RC flyers to run batteries in parallel especially LIPO by using a bridging cable.

Cycle overlap would be ridiculous as well, any attempt at active braking at those speeds would be...interesting

I'd say it's doable if everything is engineered around it. But useless.

We're not able to use 14.8v *effectively*. By effectively I mean to plug one and run a AEG as long as you would on a 11.1v. From what I gathered on ASM, excluding any failure due to fast cycle, the motor will eat the brushes much faster, which will lead to much more frequent maintenance.

If you absolutely want something above 11.1v, start with bigger 7.4s since buffer tube lipo are usually not enough to run the kind of setup that asks for a 14.8v. Since 7.4 have more space (one less cell) you could get a bigger mAh rating. Running those batteries in series will give you more voltage than needed.

Once you handle this, you can try going above, but I'm willing to bet it won't serve any purpose other than education or brief entertainment.

Well if the goal is simply to run the motor at a significantly higher RPM, if you have any interest in motor life you'd be better off modifying and installing a brushless motor lol

... And I thought 4S lipo on AEG is crazy...!

really isn't much point.. even with 14.8v dsgs you can't get them to feed.

I am typing this on my phone, since I have time to waste waiting for a bus.

Fisrt thing, all batteries are rated by their nominal voltage. For a LiPo, that is 3.7v/ cell. Times 3 cells is 11.1v. But all battery types actually have a higher actual voltage. In fact, when the voltage no-load of a pack is it's nominal, it's empty or just dead (if it's fresh off the charger). That means that a3 cells LiPo is actually up to 16.6v when full charge, as each cell can peak at 4.2v.

If you have to wire batteries in Series, you want to make sure that both are exactly the same brand and model, where made in the same batch and have the same wear/nuber of cycles. Otherwise the pack will fail, and in the case of LiPo, probably explode.

I am not sure what FET is in the MERF, but 99% of high power FETs are rated for 40v DS. It's more likely that the CMOS microcontroller fails, as it is made to operate between 10 and 15v. And there is probably not an on-board regulator for such a simple device. In theory, a homemade "simple" FET can take 40v/100A easily (yes, that's 400W).

The problem comes from the motor. The ones in our Rifles are designed for 5-7v, and we run them at 10-12v most of the time. You would have to increase the number of coils on the rotor and probably need to reduce the size of wire used to fit it. That would result in a more efficient system (less heat waste due to current), but equivalent RPM.

So all in, running a 22.2v/6 cells LiPo on a gun designed for 14v will simply result in a burnt motor, FET and potentially gearset/piston.
Keep in mind that once the insulation on the motor rotor wires is melted, that will short out your battery until the FET blows, so you also add a pipebomb in the mix, LiPos in metal tube are nasty.

I think there's enough of an airgap between the stock and the buffer tube to allow for escaping gas.. I mean when she starts to go, it'll go in the path of least resistance.. which is out the back. If it ignites.. then you have a flame thrower if you've got an open back LE stock. lol. I don't think it would pipebomb itself... but you never know.... I'm kind of interested in trying now.

Thanks for all the input guys. This was in no means something I was gonna risk without proper knowledge. I was wondering if it's theoretically even.. useful. It was more of a question I suppose than something I was even considering trying. I assumed the motor was going to burn out/meltdown, the gear axles would break, and the lipos would explode.

I wouldn't have used it with the MERF, I woulda made my own for the voltage capacity. As the lipos would be wired in series, it would cause an incredible amount of current when combined with the voltage, I figured I'd have to run 10 or 12awg wire just to even get power to the motor.
As for trigger contacts, I bought a set of "high voltage" ones from G&P (back before my mosfet days), they were $30, and are apparently good up to roughly 28V

I would also have to put in a thermal cut off, but this seems completely useless as it would overheat instantly.

As for feeding, that would be a damn near mess. You'd have to have a delayer at LEAST 1/3 the size of your sector, and that might not even be enough to help it feed properly. You would most likely get two cycles for every bb feed, and it would end up snapping the tappet plate under the stress.

Anyways, thanks for your input guys. Glad to know I was on the right track with the "holy hell the gun is exploding STAHP" theory.


TL;DR It was a theoretical question, wasn't gonna risk it. I wanted to know motor capacities, to see if a motor could even handle that much voltage

So let's say you ARE going to run it at a peak of 25v
Assuming the electronics are custom built to handle that and you're using a brushless motor
No idea what gear ratio you had in mind, but let's assume standard ratio
You'd probably need either a very long soft start on the motor to ramp up to max RPM, or you'd have to actually run herringbone gears with larger teeth for the amount of torque involved lol
The pinion gear would also need a redesign for extra torque transmission.

You'd absolutely need to use a systema revolution/PTW style piston head and air nozzle since a tappet plate would never be able to keep up with the sector gear at that speed.
You'd probably need a revolutionary light-weight swiss cheesed carbon fiber piston with a titanium rack and seriously reinforced first tooth both on the sector and piston. In fact at that speed you might even need a pre-engagement bumper to help soften the blow.

Basically your major weak points would be the springs, piston rack, and the mags being able to load BBs fast enough.

Forget about using a DC brush motor though, it's hard enough on them being run at 12.6v, anything past 14v is the danger zone. Like kos-mos said, they were originally designed with 8v in mind.

+5 for Kos Mos.

If you Ever try this insane idea, record the testing! Preferably while wearing EOD gear