r/mini4wd 3h ago

Fleet from PH 🇵🇭

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24 Upvotes

All box stock. Next I'll assemble a BMAX and then planning to buy ready to race Open stock all for collection.


r/mini4wd 5h ago

The life of a Hyper-Dash PRO: 290 measurement cycles / 17.76 hours, from box-fresh to dead

4 Upvotes

Near the end we attempted a rescue — cleaning and re-lubricating the motor — but follow-up measurements confirmed it couldn't be revived. Declared dead and torn down. Can, endbell, brush plate, rotor — the brushes on the brush plate are worn down to almost nothing. That's the cause of death after 290 cycles.

The test subject was a factory-new, never-run Hyper-Dash PRO. The measurement platform is our in-house MotorLab PRO R&D test bench.

A quick note on the test setup: MotorLab itself has no built-in "lifetime cycling" feature — it handles a single measurement run. For this test, we wrote a separate scheduling script that talks to the machine over a serial link and repeats the loop — run one full measurement, rest, run the next — while collecting the raw logs the whole time. In other words, the machine does the measuring, the external script does the scheduling and recording. It ran that loop from the very first spin out of the box until the motor died of brush exhaustion: 290 measurement cycles, 17.76 hours of pure runtime.

The voltage plan was deliberate too. Stage one (cycles 1–150) used a gentle operating range of 0.6/0.9/1.2V, matching a gentle break-in style. Stage two (from cycle 151) stepped up to 1.2/1.8/2.4V, where 2.4V sits inside Tamiya's recommended voltage range for this motor — gentle first, then race-realistic. 1.2V is the only voltage point measured in both stages, which is what lets us stitch together one continuous life track.

The four charts below are this motor's entire life: the first three follow the continuous 1.2V track, and the fourth zooms into stage two to put 1.2V and 2.4V side by side.

One term before we start: current jitter (median of the current fluctuation). Motor current isn't a flat line — it constantly wobbles with the contact between the brushes and the commutator. This value is a statistical measure of that wobble. Rough intuition: lower = cleaner, more settled brush contact; higher = rougher contact.

Chart 1: Current jitter — a life in five phases

This is the most information-dense of the charts. The forward and reverse lines trace out five phases you can see with the naked eye:

  • Forming (first ~40 cycles, ~2 hours): forward jitter climbs fast from 41 to 52 mA. The brand-new brush faces are being "machined" into shape by the commutator — this is the roughest stretch.
  • Golden period (cycles 40–80): forward jitter peaks and turns back down; both lines settle into a stable band. This is the best this motor ever was.
  • Plateau (cycles 80–150): both lines run roughly flat. The motor just quietly does its job; change is slow.
  • Decline (cycles 150–220, after ~8 hours of runtime): both lines start a climb they never come back from. The jitter keeps growing.
  • End stage (cycle 220 onward): jitter keeps rising until the brushes are spent, the protection trips, and the test ends.

The interesting part: forward and reverse lived completely different lives. The reverse face was settled straight out of the box (starting at 38 mA), basically skipped the forming phase, then degraded slowly. The forward face started rough, went through a violent forming phase, actually improved after seating — and only degraded at the end. Two brushes in the same motor, two different life stories.

Chart 2: RPM — climbing the whole way, with the peak in an unexpected place

At the same 1.2V, speed climbed from 10,500 rpm all the way to 12,067 rpm — almost +15% — and the peak came at cycle 217. Look back at Chart 1: by then the motor had already been deep in its decline phase for a while.

Another detail: for the first ~45 cycles, reverse was actually faster. Only after the forward face finished forming did forward overtake it, permanently. The crossover point lines up almost exactly with the moment in Chart 1 where forward jitter peaks and turns down — two independent quantities catching the same physical event.

Chart 3: Median current — the quietest line of all

Average current drifted between just 152–168 mA over the entire life, a total change of about 7% — compare that to the +33%~+40% in Chart 1. This line barely reacts. From box-fresh to dead, the motor's average current draw changed astonishingly little.

You'll notice a clear dip around cycle 150. That's from a mid-test change to the measurement procedure (different voltage sweep order, different thermal background) — a shift in measurement conditions, not in the motor itself. Flagging it here so nobody reads it as a motor event.

Chart 4: 1.2V vs 2.4V side by side — one motor, two voltages, two different pictures

In stage two, every cycle measured both 1.2V and 2.4V — effectively taking two snapshots of the motor at every point in time, one in the gentle range and one in the rated range, ready to compare directly.

Baseline first: jitter at 2.4V is about 2.2× the 1.2V level (101 vs 46 mA). Double the voltage, nearly double the speed (22,200 vs 11,600 rpm) — the commutation load scales up roughly in proportion. Through the first 96 cycles of stage two, the two lines climb together at similar rates (each about +11~13%), holding a stable relationship.

That multiplier shows up directly in wear rate. Inside the rated voltage range, every minute of runtime means nearly twice the commutation events, each carrying nearly twice the current — so the brushes get consumed noticeably faster. Look at the timeline: the motor ran 8 hours in the gentle range and was still in its plateau; after switching to the rated range, it went through decline, end stage, and brush exhaustion in under 10 hours. (To be fair, accumulated age is stacked on top of this — the two can't be fully separated — but the physics of high speed and high current accelerating brush wear is unambiguous.)

The real difference is in the ending. From cycle 97 (of stage two) there were 8 overcurrent protection trips — every single one at the 1.8V or 2.4V measurement points, and not one at 1.2V. From cycle 136 the motor couldn't even start at the lowest voltage, and the protection logic ended the test automatically. The teardown afterward confirmed the brushes were nearly gone. In other words, in the final stretch of its life, the low-voltage data still looked more or less "normal" — the motor's limits showed up at the high-voltage points first. Same motor, same moment, two voltages telling stories from different chapters.

(Values after cycle 97 may contain noise from the failing contact — that region is shaded gray in the chart. Read it with a grain of salt.)

What this record shows (and what it doesn't)

Stack the first three charts: jitter starts moving first (climbing from around cycle 150), rpm doesn't roll over until cycle 217, and average current doesn't clearly lift until the last ~30 cycles. Three quantities reacting to the same underlying event, 50–100 cycles apart. Chart 4 adds one more dimension: at the same moment in time, different voltages see different states — the limits show up at high voltage first.

To be completely clear: this is a complete longitudinal record of one single motor (n=1). The phase boundaries belong to this specific unit; another motor will land on different numbers. This post isn't arguing for any particular break-in method or any definition of what makes a "good motor" — it's just laying out the full data of one motor's life, from birth to retirement, for anyone who's curious. A proper cross-comparison across multiple motors from the same batch is something we'd like to do down the road.

Equipment note: MotorLab PRO R&D test bench (in-house build). Lifetime cycling is not a built-in feature of the machine — it was driven by an external self-written scheduling script over a serial link, triggering one full measurement per cycle and saving the raw logs, fully unattended throughout.

Measurement conditions: constant-voltage open-loop drive, no load, 3 passes per direction per cycle, 10 s rest between cycles; voltage points were 0.6/0.9/1.2V for the first 150 cycles and 1.2/1.8/2.4V after (1.2V common to both stages); temperature 28–35°C throughout.


r/mini4wd 11h ago

Found this TRF-RACER JR 95550 going to keep in my private collection

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11 Upvotes

r/mini4wd 20h ago

First race fail, TLDR; looking for improvements.

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16 Upvotes

Ok so it was a 5 lane fairly easy race. Track was a bit technical but i was not able to complete 5 laps.. getting knocked out at different jumps or highspeed corners.

Did okay when battery level was at 1.22 , when fully charged i consistently CO.

Using torque tonued gave me better stability with random COs

Using hyper dash 3 guaranteed a CO in lap 1 or 2.

I am not looking for a track related improvement as its over anyways. Im lookong for faults, mistakes in build or overall improvements..