About this replacement
iHome iBT74 — 3.7V Li-ion Replacement Battery (D17E19)
This is a 3.7V, 2600mAh Li-ion cell built to the D17E19 spec. It fits the iHome iBT74 portable Bluetooth speaker. When the original cell degrades and the speaker no longer holds a charge away from the wall, this is the direct swap.
- iBT74 fit: The iBT74 runs a single-cell 3.7V Li-ion pack with a compact flat form factor — 67.50 × 21.55 × 18.75mm. This cell matches that footprint and the battery connector pinout so the speaker's charging circuit and protection board communicate with the pack correctly.
- Bench tested on actual hardware: We cycled this cell through charge and discharge while monitoring the BMS. The protection circuit tripped at the correct low-voltage threshold and recovered cleanly on reconnect — no latching fault.
- Fuel gauge reset after swap: After fitting a new cell, run the iBT74 down to automatic shutdown, then charge uninterrupted to full. This re-calibrates the speaker's charge indicator. Skipping this step leaves the gauge misaligned from the first use.
Capacity fade on the iBT74 from constant top-off charging
The iBT74 spends most of its life sitting on a charging dock or USB cable between uses. That pattern — topped off at 100%, never discharged below 50% — is one of the fastest ways to degrade a Li-ion cell. The cell spends extended hours at high state-of-charge, which accelerates electrolyte oxidation at the cathode. The result is a pack that still reads "full" but delivers noticeably shorter playback as capacity fades below its rated 2600mAh. Letting the speaker discharge to below 20% at least once a month before recharging slows that process.
Audio distorting before the battery indicator reaches empty
If the iBT74 starts clipping or distorting audio while the charge indicator still shows battery remaining, the cell voltage is sagging under the combined load of the amplifier and Bluetooth radio. A worn cell can't hold 3.7V under that current draw even when it isn't fully discharged. The amplifier hits its minimum operating voltage and clips the output before the BMS trips the low-voltage cutoff. Replacing the cell restores the voltage headroom — a healthy 2600mAh cell holds above 3.4V under combined amp and radio draw until the pack is genuinely near empty.