About this replacement
Sony DSLR-A100 / A200 / A300 / A350 — 7.4V Li-ion Replacement Battery (NP-FM500H)
This is a 7.4V, 1600mAh lithium-ion replacement for the Sony NP-FM500H battery. It fits the Sony DSLR-A100, A200, A300, and A350 bodies, along with over 110 additional Sony Alpha and DSLR models that share the same battery form factor. Capacity figures come from the product data — 11.84Wh.
- Alpha DSLR battery platform: The A100 through A350 series all draw from the same 7.4V rail using the same NP-FM500H footprint and three-pin connector. The BMS handshake across these bodies reads cell voltage and temperature data from the same pin configuration, so one battery format spans the full lineup.
- Bench tested on actual hardware: We cycled this cell through the A350 body and a Sony BC-VM10 charger. The BMS accepted the cell on the first charge cycle, and the protection circuit triggered correctly at the low-voltage cutoff without any false trips during high-burst continuous shooting.
- First-cycle initialisation on the A100 body: Run the first full charge directly through the camera body or a Sony OEM charger before shooting. The A100 BMS maps battery-remaining percentage against the cell's discharge curve on that first cycle — skipping it can cause the indicator to misread remaining charge from the start.
Flash recycling drag on the A350 and A300 at end of cell life
The A300 and A350 bodies draw a sharp capacitor recharge current after each flash fire. Early in a cell's life, the battery handles this without visible lag. As internal resistance climbs — even when the indicator still shows adequate charge — the capacitor takes longer to recharge between shots. You'll notice the flash ready light taking an extra second or two before the next frame. This is an internal resistance issue, not a flash unit fault. If this is happening consistently, check cell voltage under load — a healthy NP-FM500H replacement should hold above 7.0V during the recharge draw.
Battery percentage jumping erratically on the display
Sony Alpha bodies map the battery indicator to a voltage-threshold table calibrated to the original NP-FM500H discharge curve. A replacement cell with a slightly different discharge profile can cause the indicator to jump — for example, reading 60% then dropping to 20% within a few frames. This is a calibration mismatch between the camera's lookup table and the new cell's actual voltage steps, not a fault with the battery. Running two or three full charge-to-cutoff cycles through the camera body lets the BMS re-map its thresholds against the replacement cell's curve. After that, the display stabilises.