Speed HD-9Z Compatible Battery 3.7V 1800mAh Li-ion

Speed HD-9Z / HD-120Z / HD-A10 — 3.7V Li-ion 1800mAh Replacement Battery

This Speed 3.7V 1800mAh Li-ion cell replaces the factory battery in the Sony Cyber-shot DSC-S70, DSC-S75, and DSC-S85, as well as the HD-9Z, HD-120Z, HD-A10, and HD-50Z fit models. It slots into the same battery compartment and makes the same electrical contacts as the original. Capacity is rated at 1800mAh (6.66Wh) at 3.7V nominal.

• Shared platform across HD-9Z, HD-120Z, HD-A10, and HD-50Z: These models share the same battery footprint, contact pin layout, and 3.7V supply rail. One cell fits each body without adapters or modifications.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on camera hardware and confirmed the BMS accepted the cell, the battery indicator populated on-screen, and charge termination triggered at the correct voltage ceiling.
• First-use charge cycle on the Cyber-shot body: Insert the new cell and run a full charge through the camera body before your first shoot. The Cyber-shot's battery-remaining display calibrates its threshold map against the cell's discharge curve during that initial charge cycle — skipping it leads to erratic percentage readings.

Flash recycling slowing down before the battery indicator drops

The Cyber-shot's xenon flash capacitor pulls a sharp recharge current spike after every shot. Near the end of a charge cycle, internal resistance in the cell climbs, and that spike causes a momentary voltage sag. The camera body detects the sag and throttles available current to the capacitor, which stretches recycle time — even though the battery gauge still reads partial charge. This is normal cell behaviour, not a fault. If recycle lag becomes unworkable mid-session, swap to a freshly charged cell; the threshold where sag begins is typically around 3.5V under load.

Battery percentage jumping erratically on the Cyber-shot display

This happens when the camera's indicator firmware maps voltage thresholds that were calibrated to the original Sony cell's discharge curve, and the replacement cell's curve sits slightly differently. The display reads voltage, converts it to a percentage using a fixed lookup table, and reports a number that doesn't track linearly with actual remaining capacity. The fix is one complete charge-to-discharge cycle run entirely through the camera body. After that cycle, the BMS recalibrates its reference points and the percentage display stabilises.