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Richman992’s AK Builds Thread

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I'm creating this thread as a way to keep track of progress in my builds, and have everything in one place. It will help me organize and see a timeline of things, and also opens things up for questions or suggestions.

With that out of the way, this is the current project:

Line Air gun Font Trigger Engineering

Water Trigger Font Air gun Engineering

If you've played the Nuka-World expansion of Fallout 4, you probably recognize this gun. I've flipped the images because in the game, the charging handle and selector switch are on the left side of the gun. Since I don't have the ability to make a new receiver/bolt, I'll have to get as close as possible with the E&L AKM receiver I have:

Air gun Trigger Wood Shotgun Gun barrel

I was fortunate enough to have the handguard and suppressor on hand already. Thanks to Craigslist, I was able to score a beat up shovel to steal the handle from. Mounting the "stock" was very easy, once I cut it down I simply marked where the rear trunnion goes into the stock, and bored it out until it was a tight fit.

The next thing I'll be doing towards this build is a mag conversion. I managed to get my hands on a real steel slabside magazine, so I will be converting that into an airsoft magazine for this. I'll be practicing on a couple Chinese magazines before I cut into the slabside, though. I'll be taking pictures throughout the process for anyone curious about doing their own conversions.

I'm also currently working on an Aftermath Kraken for a teammate. The goal with this one is pretty simple, he just wants it to be a "sleeper" with better response and a higher ROF. It will get the basic HT motor, 13:1, reshim/aoe that I do with most of my personal guns. I managed to pull it all apart today to get started, and was greeted by yet another Cyma gearbox:

Light String instrument accessory Red Material property Trigger

Guitar accessory String instrument Audio equipment Crankset Auto part

At least I'll have spare shims for the rebuild.
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Looking at your screenshots we can derive the following:

Tienly 45K
1. 82.35A and 714.3W to cycle implies 8.67v
2. 85.53A and 720.2W to cycle implies 8.42v

LCT stock motor (unknown spec)
1. 48.93A and 510?W to cycle implies ~10.42v

I'm assuming from these that you're running on 3s lipo but experiencing significant sag (~33%) due to heavy current draw. However, pulling 50A on a stock motor is not good either and I've only seen that when complete lockups happen - a G&P M140 motor I was testing recently stalled at 48A. Semiauto is very hard on the motor, and the heating of the motor endbell is indicative of high current being passed whether it's accelerating the motor out of a standstill, or very harsh active braking algorithms. I would like to see what full auto amp draw looks like, but the Tienly 45K is a 12t motor so expect it to run hot

My questions
1. What does the Gate Titan report for amp draw when the motor is ran with no load?
2. What battery are you using for testing?
3. Why is your sector gear red?
4. What are your other motor-related settings on the Titan? Precocking, ROF control/stabilizer, Smart Trigger, Active Braking,

My recommendations as of right now
1. Upgrade/downgrade Titan software and see if symptoms persist. Ensure motor tab connectors are tight
2. Remove motor brushes, clean commutator and brush faces, and re-break in motor (3-4v for half an hour, stop motor periodically to cool off and clean out brush dust)
3. If you have access to an external ammeter to confirm amp readings in full auto that would help

Things to keep in mind
1. The Titan is a black box, you don't know how its algorithm calculates current flow or how accurate their measurement circuit design is in the first place. That's why I recommend getting a second opinion
2. You are right on the edge of what Tienly recommends for usage scenario, M100 spring minimum
3. Titan was supposedly designed for 300A, it throwing an overcurrent DTC is kind of worrying.
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1. Damn 24A unloaded is a very hot wind, I don't have a 12t motor but I do have an ASG 45K 13t laying around somewhere unused. If I can find it I'll try to run it unloaded to see how the numbers compare.

The voltage drop calculations off of these screenshots are
255.1W/24.68A=10.33v, 82.03% (17.97% sag)
243.3W/23.58A=10.32v, 81.90% (18.10% sag)
This is very heavy sag with no load. Just to confirm, this is with the motor completely removed from the gearbox correct?

2. Averaging the two readings above for simplicity, we get the following calculation (excuse my poor handwriting). Explanation below

Treating the average current draw as a simple resistive load allows us to use Ohm's Law, V=IR
solve for the apparent resistance of the load (motor) notated as R_L, 0.43Ω.

Using Kirchoff's Laws we can then calculate the internal resistance of your battery.
R_I is simulated battery internal resistance (not notated as I_R as that implies a current measurement). Ignoring the Gate Titan's own internal resistance and any voltage drop caused by semiconductors (nothing is 100% efficient) we have the circuit diagram shown. The point labeled 10.3v is where the Gate Titan is monitoring voltage.
12.60v-10.3v=2.3v voltage drop seen at battery under load
Ohm's Law again, V=IR
solve for R_I, 0.096Ω. Hmm.

At face value, looking at nearly 100mΩ internal resistance is terrifyingly high. However, if we account for other resistances like connectors (averaging around 8mΩ from my measurements) and changing the 2.3v value to 1.0v to compensate for the MOSFET internal voltage drop we still get I_R=34mΩ. Looking through my data of tested lipos the closest one I could find to that IR is one of the prototype packs Guges sent me, given ID# GUGES10 by me, which claims to be a 2200mAh 20C (44A) pack but was actually 2240mAh 14C (30A) as measured.

Your battery is grossly overstated in terms of discharge rating, I would ensure it's actually a 2200mAh capacity if you can (discharge to 2.50v/cell, let cool, charge to 4.20v/cell).

3. Ah interesting, it catches the entire gear in that pic

4. Understood. As your testing shows, active braking adds a noticeable but small amount of current per 'cycle' but even when disabled your readings were very high

If you want to verify the Titan's readings are in the ballpark, what you could do with your voltmeter is connect it to the battery (through the tap?) and put a camera on it while cycling the AEG on full auto. Commercial voltmeters may not have a high enough refresh rate to catch important data points when an AEG is cycling in semiauto. Find the lowest volt reading in the footage, and compare to what the Titan reports as it should be similar.

3-4v via 1s lipo is what I've done in the past before I got a bench power supply, salvaging good cells off of otherwise defective batteries is not for everyone though so I understand if it's unconventional. Other options could be
1. for normal motors (not one that draws 24A unloaded lol) 18650 cells are plentiful and cheap these days so getting a holder with solder/tab terminals means you can use them as a 1s power source. Good 18650 cells will have discharge ratings of 15A or higher
2. RC hobbyists in the past have used rechargeable C or D cells in a holder for a large capacity motor break-in power source. NiMH D cells are usually around [email protected]
3. if you have a USB-C PD port on a device or adapter you could DIY an adapter for high turn count motors. USB PD is able to deliver a maximum of 5A and a lot of the AC adapters I see have a maximum of 2.4A. I've broken in a lot of motors at 4.0v and a some of the ones I use are below 2.4A (Ares slim HT, Tienly 25K, JG blue) or just above (TM EG700, Arcturus 19t, G&P M140 HT).
As with everything unregulated, fusible links are recommended and please monitor temperatures when in use.

Breaking in motors is not absolutely necessary but I would highly recommend at least running the motor unloaded before sealing it up in an AEG both to confirm that it actually works, and so the first power cycle it has isn't under heavy load which is more likely to spark and pit/burn the commutator. Pencil eraser works good for cleaning the commutator surface assuming it's in good condition and doesn't need to be re-cut. I use mild abrasive in roughly the same diameter as the motor comm (think Dremel sanding stone) to resurface the brush. The break-in process allows the brush to wear to the comm curvature for maximum contact, with brand new brushes some of them only make contact at the top and bottom of the brush which results in the same amount of current flowing through a much lower surface area, which means greater resistance, which means lower motor performance and higher heat generation.

Dielectric means it's an insulator, Superlube is what I use for airsoft and I also used it when redoing the ignition on my 4Runner. The grease waterproofs the spark plug connection, while simultaneously deterring discharge happening outside the combustion chamber (spark plug corona).
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old adage “if the motor and wires are heating up, it’s probably a drivetrain issue”
This is usually true, heat in wires is an indicator of relatively high current draw. If a setup is performing normally and then suddently stumbles and wires get hot, then something is increasing drivetrain loading which usually means something is damaged.

aotsukisho, to answer your question regarding the motor, yes it was fully removed from the gearbox and even motor cage for the tests.
That is very worrying. I dug out my old ASG 45K and adjusted my power supply

Amp draw is right at 5A. Seemed to be funny so I checked the PSU, it's good for 10A and no limiting was in place so the reading is accurate.

Similar amp reading when run off of a lipo

ASG surprisingly has a data sheet for the 45K here: Motor, INFINITY CNC U-45000, long axle
Page 1 is the dyno graph, and at the top right we see V=10.76, I=6.268. My amp draw results are lower, but I got the motor secondhand and I am unsure of its prior history and due to me not using low turn count motors I have not torn it down for cleaning/rebuild. Also from the same page, the stall current is I=93.682 which means the motor will draw over 90A if the gearbox gets locked up. Given that dropping down one turn for a 12t motor (Tienly 45K) the stall current shouldn't be that much higher, I'd guess 110-120A which is lower than what Gate claims the Titan can handle.

Tienly does not have any dyno sheets for their motors that I could find, but there was a table I found that lists maximum power output of all of their motors to be 450W, and the GT-45K is supposed to draw [email protected] If your 45K was completely load-free and the Titan was reporting 23A then something is seriously wrong. Titan could be defective, or Tienly might have a shorted winding. The high amp reading on the LCT motor kind of points to the Titan but both could be true at the same time.

Definitely try with a better battery though, like I mentioned before the Titan datalogging frequency is unknown so the actual highs and lows could be more extreme. If the battery voltage sags low, the motor will have to draw more amps to compensate since the amount of power it needs to cycle is more or less constant. Watts = Volts*Amps

The heat appears to be normal lol. This measurement was taken after around 30 seconds of being run at 11.1v, ambient temp is around 75°F

As I’ve offered the motor to Leo once I get this all sorted out, I’d like to offer aotsukisho this Ovonic battery for testing purposes. I’d be very curious to see what you found with it. I just wanna hang onto it for a little longer since it’s almost like another control variable for my testing at this point.
No problem, if you'd like to send me the motor too I can test it on my power supply before forwarding it off to Leo. The Ovonic battery can be returned to you if you'd like.

Also noted on the grease. I’ve used dielectric grease for trailer wiring and bulbs to prevent corrosion, just wanted to touch all my bases and make sure it wasn’t causing some weird interference or shorts. A google search probably could have saved me there, lol.
Ah yeah the grease repels water and is heavy enough to stay put. Very handy stuff.
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Sorry for double post but was thinking about it, and if you have automotive stuff laying around you might have something you can use to test the Titan's readings especially with a 3s lipo (close to automotive "12v").

I use LED bulb load resistors as a discharge load to fully kill 2s lipos, 12Ω 25W. If we use that resistor in the place of the motor, we can use Ohm's Law to see what the Titan should be reporting:
Solve for the current, I=V/R=1. The Titan should report 1A or less as both peak and constant - resistors do not have current spikes like electric motors do.

Test setup, using an unused endbell as an interface for the Titan's motor connectors

Tried holding the trigger for 20 seconds, but looks like the Titan didn't notice. I'll have to find something with heavier draw.

Headlights and other high output bulbs should give an amp rating for them like this one, Sylvania 9007SZG rated for 55W (4.29A) or 65W (5.08A) at 12.8v. I happen to have something similar laying around

Here is an old Bosch foglight that came off of a 1987 BMW 325e, it happens to be in the 55W class. Testing on 11.1v on the power supply shows almost 4A draw, this should be enough for the Titan to think it's a motor

Galaxy S21 HDR on point with this photo

Updated test setup

The Titan is happy with the amp draw on this load, so it works. Holding full auto for 10 seconds for a solid reading

Turnigy wattmeter reads 4.1-4.2A. Let's compare this to the Titan's readings.

lol. It doesn't even read voltage correctly for some reason, the wattmeter reads 0.06v high compared to my multimeter/power supply.

So yes, Gate Titan reporting is hilariously incorrect.
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I am sending this info to Gate...they are looking into this.
I will screenshot the version # of the software when I get home, if Gate wants the serial number for this Titan I can provide that as well
The #17 marked pack is a 3s version of a pack I tested, #3 1260mAh 14C (20A)
The #8 marked pack is a 3s version of a pack I tested, #10 2240mAh 14C (30A)
Zippy pack should perform well, I have not bought that specific config but all of the Zippy's I have are great especially considering the price
Same with the Tattu
Really want to see how the Matrix one does lol

The only things that have me worried is that 2 separate mosfets had nearly identical (and ridiculously high) readings
Both are Gate Titans with I'm guessing the most up to date version of Advanced firmware, barring any significant hardware revision between the two they are likely to report similarly precise (but inaccurate) readings. You mentioned they are both brand new, if you bought both of them from the same vendor at the same time I would assume they are identical.

The Aster might be using an identical voltage/amperage measuring circuit/software, from Gate's perspective why redesign something when you can reuse the Titan design. I would check the Jefftron's readings for a true second opinion.

I don't think I remember you mentioning downgrading the Titan firmware, were you able to test with an older version?

and the excessive heat generated by the motor.
Did you take temperature readings? Motors are fine at 150°F, human skin is not.

BTW you mentioned in the original post, the ETU wires getting hot is also not very surprising. Gate wires are low strand count and I do not consider them to be high quality either.
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Hello and welcome Jakub, thank you for the information. Here are some responses

By the way, the measurement you did using 5 A current is at the limit of TITAN V2 measurement noise (accuracy +- 20% for 5A).
Reading 5.4A average is an error margin of ~30% compared to 4.11-4.19A of the wattmeter. I will try to find a truly linear lower-ohm load to try to get amp draw in the 10-20A range as that is where most of my motors run by Gate ETU's start at, unless there is an optimal range where the margin of error is smallest?

The biggest measurement advantage of TITAN is that TITAN performs current measurements 10000 times per second (true RMS). Unfortunately, the watt meters in the photo cannot operate at such a high frequency. Thanks to this, the TITAN is able to measure and include in the measurements the current peaks occurring during the motor start as well as during the commutation itself on the carbon brushes.
I understand this, my wattmeter operates at 1-2Hz and it is why I am not talking about peak amp draw. The reason why I held the trigger down for 10 seconds, to get a constant amp reading and mitigate the effect that the inrush current of the lamp has on the average reading.

Another reason for the differences in measurements (voltage measurements) is that the TITAN voltage measurement takes place within the PCB, inside the gearbox; not on the wires, not on the DEANS-T.
Under load, near the end of the 10 seconds of trigger pull (maximum sag) the wattmeter reports 11.79v. The Titan reported a minimum reading of 12.26v, which is ~4% high. If we assume the actual voltage at the wattmeter is 11.73v since my wattmeter reports +0.06v, then the error is ~4.5% high.

In the measurement shown, the "WATT METER" measures the voltage at the battery terminals and does not take into account the voltage drop across the wires between the battery and the ETU.
Correct, which is why I would assume the voltage that the Titan 'sees' should always be lower than a measurement taken from the battery especially since the wattmeter itself causes additional voltage drop.

I can mention that TITAN has dedicated algorithms to compensate for the mentioned inconvenience.
If it is possible in a future software update, I would like to see separate readings for 'actual' voltage (at the Titan and/or motor connections) and a software-compensated battery voltage. This would be a good troubleshooting stat to see if connectors are not mating well or have degraded over use, or if an improperly done solder joint has gone bad on a connector swap for example.

A few questions, if the answers are allowed to be disclosed:
1. What is the minimum current flow allowed before the Titan v2 cuts power and reports DTC? I measured ~0.3A for a short while on trigger pull during the first test with power resistor load
2. At what amperage is the Titan v2 the most accurate? I will see if I can order a power resistor and redo the test
3. Were there any running changes in the Titan v2 meter that could have an effect on measurements taken from early vs late serial#?
4. Does the Aster use the updated v3/NGRS/TII voltmeter design or does it have a unique one?
5. Does the Titan use PWM on the output even with ROF control disabled? This could lead to inaccuracy with my wattmeter even with an ohmic load

Here's the info from GCS for the Titan v2 I used for testing, can provide serial numbers if needed
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As for the load, it is best to use an electoral load, because resistors heat up and change their resistance, so the current flowing through the load will also change.
What would you recommend as an ideal test load? I tried to mitigate changes in resistance by taking average readings, but anything to increase repeatability of the experiment is worth looking into

We are doing tests on our side and will send you information in which current range the measurement accuracy is the highest on the TITAN side. Once it's done, we will publish tables for your reference.
Awesome, looking forward to seeing them

In this case, both the wattmeter and the TITAN V2 show the correct readings, the difference being that the TITAN shows a stable voltage when there is no shot (during idle), while the wattmeter shows the voltage continuously (that is, it does not distinguish whether there is a shot or not). If we connected an even higher load then the wattmeter would probably show an even lower voltage value, meanwhile the TITAN would show a reading very close to 12.26v. We used this approach because for a standard user it doesn't matter what the voltage is after the voltage drop on the TITAN power cables, only what the battery voltage is.
Understood, for future experiments I'll record the idle voltage before putting the Titan under load.

This is a very interesting idea, however TITAN V2 is not by design a measuring device, we just try to collect the most useful information for the standard user. We may consider to add such option in TBT2 in future. However if you are looking for such a function now, this is currently available in Blu-Link.
Understood, just my wish list. lol

Ad1. Minimum current before TITAN cuts off power when trigger is pressed is around 3A. - then the motor disc error appears
Ad2. We will check it out and come back with more information on it
Ad3.Nothing has changed in this matter
Ad4.All ETUs have voltage measurement circuit on the power supply. Therefore each GATE ETU will show a similar measurement result.
Thanks for the info. Answers are clear!

The Gate doesn’t allow me to cycle the motor outside the gearbox for an extended amount of time (code for no sector movement)
Is cycle detection disabled?
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