JBL Tune 510BT Compatible Battery 3.7V 450mAh Li-Polymer

JBL Tune 510BT / Tune 500BT — 3.7V Li-Polymer Replacement Battery (02-553-3494)

This is a 3.7V, 450mAh Li-Polymer cell that fits the JBL Tune 510BT and Tune 500BT wireless headphones. It replaces OEM part numbers 02-553-3494, 603028, and 523028. The cell measures 30.00 × 30.00 × 6.20mm and sits inside the left earcup housing.

• Tune 510BT and 500BT shared platform: Both models run the same physical cell format, connector pinout, and BMS voltage thresholds — 3.7V nominal with a 4.2V charge ceiling. One part number covers both headsets.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Tune 510BT. The BMS accepted the pack without error flags, held cutoff at 3.0V under load, and topped out cleanly at 4.2V on the charger.
• First-charge protocol for the Tune 510BT: New cells ship at storage voltage — around 3.6V. Plug the headset into USB-C and let it charge uninterrupted to 100% before the first use. The headset's fuel gauge calibrates on that first full cycle, so the battery indicator will read accurately from that point forward.

Why the Tune 510BT cuts out mid-call on a new battery

The Tune 510BT runs its Bluetooth radio and audio codec simultaneously during calls. That combined draw creates brief current spikes the BMS reads as an undervoltage event if the cell hasn't been through a full conditioning cycle. The BMS trips the cutoff to protect the cell, dropping the audio connection. Run two or three full charge-discharge cycles and the spikes stabilise within the BMS's tolerance window.

Talk time shorter than rated on the first few charges

Li-Polymer cells don't reach full usable capacity straight out of storage. Electrolyte activation across the polymer separator takes three to five charge cycles to complete. Each cycle, the available capacity steps up incrementally until it stabilises at the rated 450mAh. If talk time feels short on the first charge, cycle the headset fully — charge to 4.2V, discharge under normal use — and repeat three times before drawing any conclusions about cell performance.