About this replacement
Apollo 26.517 — 4.8V Ni-MH Replacement Battery (26.517)
This is a 4.8V, 2500mAh Ni-MH battery for the Apollo 26.517 wireless crane remote control. It fits the overhead crane and lifting equipment remote directly, restoring power to the handheld transmitter unit. Voltage and cell count match the original Apollo specification.
- Apollo 26.517 remote compatibility: The 26.517 remote uses a 4.8V Ni-MH cell pack — four NiMH cells in series. This battery matches that voltage rail and connector footprint, so the remote's internal charge circuit and low-battery detection threshold operate as the original manufacturer intended.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a Ni-MH compatible charger and verified the cell pack holds stable voltage across moderate load. The pack reaches full capacity within the standard charge window and does not show premature voltage collapse under intermittent relay-activation loads.
- Infrequent-use charging protocol: Crane remotes often sit idle for weeks at a time. Top up this battery once a month during idle periods — Ni-MH cells left fully discharged for extended periods develop voltage depression and may report false low-battery readings on the next use cycle.
Solenoid activation causing power dropout on the 26.517 remote
When the remote triggers a crane solenoid or contactor, the inrush current spike can briefly drag cell voltage below the remote's cutoff threshold. This is more common with a partially discharged pack. The remote interprets this dip as a dead battery and shuts down mid-operation. Always start solenoid-activation tasks with a fully charged pack — cell voltage should read at or above 4.8V before beginning a lift cycle.
Remote showing low battery immediately after fitting a new cell
A freshly installed Ni-MH pack ships at storage voltage — typically 30–50% state of charge. The 26.517 remote's low-battery indicator triggers when resting voltage sits below its detection threshold, which a storage-state pack may fall under. This is not a faulty cell. Connect the battery to the Apollo charger and complete one full charge cycle before first use — the indicator will clear once the pack reaches operating voltage.