About this replacement
Apollo 26.517 — 4.8V Ni-MH Replacement Battery (26.517)
This is a 4.8V, 2000mAh Ni-MH battery for the Apollo 26.517 crane remote control transmitter. It restores power to the wireless hand unit used to operate overhead cranes and industrial hoisting equipment. Match the part number 26.517 before ordering — this battery is specific to that transmitter system.
- Apollo 26.517 transmitter fit: The 26.517 remote runs a 4.8V NiMH cell pack to supply stable voltage to the RF transmitter board and control circuitry. Voltage and connector format must match exactly — substituting a higher-voltage pack will damage the transmitter logic.
- Bench tested on actual hardware: We cycled this pack through repeated solenoid-activation sequences on the bench. The BMS held voltage above 4.4V under inrush load without triggering a dropout or cutoff event.
- Monthly charge cycle for stored remotes: Apollo crane remotes often sit unused for weeks between lifts. NiMH cells self-discharge at roughly 1–3% per day — a remote left uncharged for two months can drop below the transmitter's minimum operating voltage and fail to power on at all. Charge the battery once a month during idle periods.
Solenoid activation causing power dropout on the 26.517 remote
When a crane operator triggers a hoist command, the solenoid or relay on the crane draws a sharp inrush current through the control circuit. A partially discharged or aged NiMH pack can sag below the transmitter's minimum voltage threshold during that spike — the remote drops out mid-command. This is not a transmitter fault. The fix is a fully charged battery rated at the correct 2000mAh capacity. A fresh charge brings pack voltage to approximately 5.5–5.6V open circuit on a 4.8V NiMH, giving enough headroom to absorb the inrush without cutoff.
Remote shows low-battery indicator immediately after fitting a new cell
A new NiMH battery ships at storage voltage — typically 4.0–4.2V on a 4.8V pack — not at full charge. The 26.517 transmitter reads this as a low-battery condition and flags it immediately. This is expected behaviour, not a faulty battery. Connect the remote to its charger and run a full charge cycle before use; pack voltage should reach 5.4–5.6V and the low-battery indicator will clear.