Schwing Betonpumpe AK2 Replacement Battery 7.2V 2000mAh

Schwing Betonpumpe AK2 — 7.2V Ni-MH Replacement Battery (491001057)

This 7.2V 2000mAh Ni-MH battery replaces OEM part 491001057 in the Schwing Betonpumpe AK2 concrete pump wireless remote. It fits the handheld transmitter operators use to control pumping functions from a safe distance on active construction sites. Voltage and cell count match the original pack exactly.

• Betonpumpe AK2 remote compatibility: The AK2 transmitter runs a 6-cell Ni-MH arrangement at 7.2V nominal. That voltage rail drives the RF module and solenoid-trigger logic simultaneously. Any deviation in cell count or voltage class causes the remote to fail pairing or drop commands mid-operation.
• Bench tested on actual hardware: We cycled this pack through solenoid-activation sequences and monitored the BMS response under inrush loads. Voltage held within spec across repeated trigger events, and the protection circuit did not trip during normal command bursts.
• First charge before field deployment: Ni-MH packs ship at partial storage charge — typically 40–60% of rated capacity. On an AK2 remote, a partially charged cell cluster will read low-battery within minutes of first use. Charge the pack fully before taking the remote to site.

Solenoid activation causing power dropout on a new battery

When the AK2 remote triggers a solenoid or relay command, the transmitter draws a short inrush current spike — noticeably higher than idle draw. A Ni-MH pack that has been sitting discharged for weeks has elevated internal resistance, even if it shows some voltage on a meter. That resistance causes a voltage sag under the inrush load, which the remote's under-voltage detection interprets as a dead battery and shuts down. Fully charging the pack before use brings internal resistance back down and eliminates the dropout.

Remote showing low-battery immediately after a new pack is installed

A fresh replacement pack at storage voltage — around 1.0–1.1V per cell — will read low on the AK2's battery indicator the moment the remote powers on. This is not a faulty battery. The remote's fuel-gauge circuit reads resting voltage, and a Ni-MH cell below 1.2V per cell registers as depleted. Connect the pack to a Ni-MH compatible charger and bring it to full charge before assuming the battery is defective. After a full charge cycle, resting voltage should sit at approximately 1.4V per cell, and the low-battery warning will clear.