About this replacement
Micsig STO1000 Series — 7.4V Li-ion Replacement Battery (MS-BA-A750)
This 7.4V 7500mAh (55.5Wh) Li-ion battery replaces the original pack in the Micsig STO1000 portable digital oscilloscope line. It fits the STO1000, STO1000C/E, STO1102C, STO1102E, and several additional models in the STO1000 series. Swap it when the original cell no longer holds a charge through a full field session.
- STO1000 series compatibility: All STO1000-series units share the same 7.4V two-cell battery bay, connector pinout, and BMS handshake protocol — that's why one pack covers the STO1102C, STO1102E, and related variants without modification.
- Bench tested on actual hardware: We ran this pack through the STO1000's power-on initialisation and probe channel activation sequence. The BMS passed voltage and temperature checks at startup without triggering an error state, and the protection circuit held steady through the current spike when both probe channels came online simultaneously.
- Post-install calibration on the STO1000: After fitting this battery, run a full calibration cycle through the STO1000's instrument menu before taking it into the field. The oscilloscope maps battery state during that calibration pass — skipping it causes the low-battery indicator to fire early on your first measurement session, even with a fully charged pack.
STO1000 shutting down mid-measurement despite showing charge
The STO1000 draws a sustained load across both probe channels during active signal capture. If the battery cell voltage sags below the BMS protection threshold under that combined load — even briefly — the unit cuts power to protect the pack. A degraded original battery reaches this sag point well before the display reads empty. This replacement cell maintains a flatter discharge curve at 7.4V nominal, keeping the voltage above the BMS cutoff floor during sustained dual-channel logging sessions.
STO1000 not recognising new battery after long storage
If the pack sat in a warehouse or carry case for months, the cell voltage may have dropped below the BMS recovery threshold — typically around 2.5V per cell, or 5.0V across the pack. At that level, the BMS enters sleep mode and the instrument shows no charge or refuses to boot. Connect to a known-good charger rated for 7.4V Li-ion and leave it for at least 30–60 minutes without interruption to allow the protection circuit to wake and accept charge current. Once voltage climbs above 6.0V, the BMS re-initialises and normal charging resumes.