u/BlackBird11Fox

Hey everyone,
New to deep battery testing and processing a large batch of cells on my SkyRC MC3000:

• Molicel INR21700-P42A (4000mAh)
• Molicel INR18650-P28A (2800mAh)

Most cells are currently at 3.45V. I want to check their full true capacity, check IR for grouping, and leave them at 3.65V storage voltage when finished.
Since the MC3000 lacks a native "Triple-Stage" (Charge > Discharge > Storage) automated mode, I need the fastest manual/automated workflow.
My questions:

• Best workflow? Should I CHARGE to 4.20V first, then run a CYCLE (D>C) with target charging set to 3.65V?
• Capacity reading: Do I trust the Charge or Discharge mAh for health grouping?
• Cutoffs: Is a discharge cutoff of 2.75V optimal? What termination amp prevents the "endless" looping at the end of cycles?

Thanks for any profile settings or shortcuts you can share!

TL;DR: Batch testing Molicels at 3.45V on MC3000. Need settings/workflow to get true mAh capacity, check IR, and end at 3.65V storage voltage automatically.

EDIT / UPDATE 2nd of June 2026:
Standardized Workflow & Settings for Bulk Testing
Thanks to everyone for the amazing input! Based on the advice from u/VintageGriffin and u/Embarrassed-Work2198, I have dialed in the perfect, efficient workflow for processing these 60 Molicel cells. Leaving this here for future reference if anyone else runs into the same bottleneck:
The Hardware Setup:

• Capacity Tester: SkyRC MC3000
• Bulk Pre-Chargers: Two Xtar VC8S units (budget-friendly way to bulk-charge 16 cells at 1A simultaneously to save MC3000 time).
• True IR Measurement: Ordered a dedicated YR1035+ micro-ohm meter with spring-loaded matrix test probes. (The MC3000 IR readings fluctuate too much for accurate matching, and AC 1kHz is the manufacturer standard anyway).

The Workflow:

1. IR Testing (First Step): Run through all cells while they are at storage voltage (~3.45V) using the YR1035+. Since the middle voltage plateau is flat, IR readings are perfectly stable here.
2. Pre-Charging: Bulk charge the cells to 4.20V in the Xtar VC8S bays to save time.
3. Capacity Test (MC3000): Pop the full cells into the MC3000. Run a flat discharge test at -1.0A per slot down to 2.75V target cutoff.
4. Storage: Pop them back into the cheap chargers or run a quick storage program on the MC3000 to bring them back to 3.65V.

MC3000 Exact Settings Used for FPV Pack Matching:

• Discharge Current: -1.0A (This prevents the MC3000 from hitting its 15W thermal limit and throttling down mid-test, which skews mAh data).
• Discharge Reduce (Ramp Down): OFF (Crucial for high-draw FPV packs. We want to measure the capacity under a constant load without "cheating" the voltage sag at the end).
• Cutoff Voltage: 2.75V (A safe middle ground. While Molicel rates down to 2.50V, 2.75V protects the cells from steep voltage drops and aligns better with real-world flight limits).
• Termination Current: Left at default 0.21A (0.05C) for charging. Changing it to 0.1A adds negligible mAh but takes ages.

Mapped everything into a clean Google Sheets document, sorting by Tested Capacity to build closely matched 6S1P packs. Thanks again for the help, this saved me weeks of slow testing!

TL;DR: Pre-charging in cheap bays (Xtar VC8S), discharging at -1.0A flat on the MC3000 down to 2.75V (D.REDUCE: OFF) for consistent capacity data, and using a dedicated YR1035+ meter at storage voltage for true AC 1kHz internal resistance matching.

Hey everyone,
I’m currently facing a really weird bootloop issue with my Oral-B iO Series 9 after doing a battery replacement, and I could really use some expert advice.
The Backstory:
During the replacement process, I accidentally inserted the 14500 battery the wrong way around (reverse polarity) for a brief moment. After realizing the mistake, I took it out and inserted it correctly. I've tried multiple different batteries (the old Vapcell H10, a fresh Keeppower 1000mAh, and two original Sanyo 800mAh cells) – all of them are fully charged.
The Current Symptoms & What I’ve Diagnosed So Far:

• Voltage is fine: I used a multimeter to check the board directly at the B+ and B- solder points. It reads a solid 4.2V. The physical spring contacts are definitely hitting the battery.
• Thermal Camera check: I checked the naked board with a thermal camera. No components are getting hot, nothing is smoking, and there is no burnt smell.
• The Bootloop: * If I put the toothbrush on the standard inductive magnetic charger, it does absolutely nothing (completely dead/black screen). • If I put it into the Power2Go wired travel charging case, it suddenly comes to life! It boots up, shows the "iO" logo, then shows the battery bar screen with 79%, and then immediately restarts. It has been stuck in this endless reboot loop for over 2 hours now.

What I've already tried to fix it:

1. Capacitor Reset: Took the battery out, held the power button for 30+ seconds, and left the board completely unpowered for 15+ minutes to clear the volatile memory. No change.
2. App Connection: Tried to spam the Oral-B app via Bluetooth the exact second the screen flashes on in the travel case, but the boot window is too short to establish a stable handshake.

It seems like the hardware survived the reverse polarity (since the screen and CPU work), but the BMS (Battery Management System) or the MCU firmware seems completely bricked/corrupted regarding the voltage validation.
Has anyone ever successfully bypassed this specific bootloop or forced a hard factory reset on the iO9 board when it's stuck like this? Is there a specific SMD diode or trace that usually blows open during reverse polarity that causes this 79% validation error?
Thanks in advance for any tips!