About this replacement
Midland ER300 / ER200 — 3.7V Li-ion Replacement Battery (BATT20L)
This 3.7V 2200mAh Li-ion battery replaces the original BATT20L cell in the Midland ER300 and ER200 portable DAB digital radios. It slots into the same battery compartment as the factory unit with no modifications. Capacity is 2200mAh (8.14Wh), matching the original specification.
- ER300 and ER200 compatibility: Both models run the same 3.7V power rail, use the same physical battery form factor, and share the BATT20L part number — one cell fits both.
- Bench tested on actual hardware: We ran this cell in an ER300 unit and confirmed the BMS accepted charge immediately from the standard dock, with no error flags or protection tripping during the charge cycle.
- Station list re-scan after installation: After installing this battery, let the ER300 complete a full auto-scan before manually tuning — DAB station lists are held in volatile memory and a fresh power cycle from a flat or swapped battery resets the stored station index.
Radio cutting out mid-station at low battery on the ER300
The DAB decoder in the ER300 needs a stable voltage to process the multiplexed OFDM signal continuously. When the cell drops below roughly 3.2V under load, the decoder loses the stream before the radio visually shows "low battery." The result is audio dropping out or the radio resetting to standby mid-broadcast — not a tuner fault. A replacement cell holding a full 3.7V charge eliminates this cutout behaviour.
Reception noticeably worse than before in weak signal areas
In areas with a marginal DAB signal, the ER300 pushes its RF front end harder to lock onto a transmitter — and that draws more current from the battery. A degraded or partially charged cell sags under this extra draw and can no longer sustain the voltage the RF circuit needs for full sensitivity. The result is frequent re-buffering or a blank station list, even though the aerial and location are unchanged. Charge the replacement cell fully before testing reception in a weak signal area — the radio needs the full 3.7V headroom to perform the signal search correctly.