About this replacement
iRobot Looj 120 / 130 / 150 Series — 7.2V Ni-MH Replacement Battery (11200)
This 7.2V, 3600mAh Ni-MH battery replaces OEM part 11200 in the iRobot Looj Gutter Cleaning Robot 120, 130, 150, and Looj Gutter Cleaner models. It restores drive and auger power to units that have lost capacity through age or cycle wear. Dimensions are 133.17 x 46.55 x 22.47mm — confirm these against your pack before fitting.
- Looj 120/130/150 platform fit: All three models share the same 7.2V battery bay, connector layout, and BMS handshake. The pack slots directly into the same cavity across the range, so one SKU covers the full Looj lineup listed above.
- Bench tested on actual hardware: We ran this pack through full charge-discharge cycles on Looj hardware and monitored BMS cutoff thresholds. The protection circuit triggered correctly at low-voltage and recovered cleanly on the next charge cycle without faults.
- Post-storage re-initialisation: Ni-MH cells lose charge in storage. If this pack arrives partially depleted, place the Looj on the charger for a full uninterrupted charge before first use — the BMS needs to see a complete charge cycle to report capacity accurately to the device.
Why the Looj stops mid-gutter and won't restart immediately
The Looj auger motor draws a current spike each time it hits a compacted debris load. On a degraded Ni-MH pack, cell voltage sags hard under that surge, tripping the BMS overcurrent cutoff. The robot stalls, and the BMS holds the cutoff for several seconds before allowing restart. Replacing an aged pack resolves this — a fresh 3600mAh cell maintains voltage above the BMS trip threshold through debris contact.
Looj shows full charge indicator but stops working after a short run
This is capacity fade — the pack accepts a surface charge quickly, the indicator reads full, but usable capacity is a fraction of rated. Ni-MH cells degrade fastest when stored discharged for extended periods between seasonal use. A replacement pack with fresh cells will hold the full 3600mAh across a complete gutter run. After fitting, run one full charge-to-depletion cycle to calibrate the indicator.