Roomba 500 series battery case

thingiverse

Battery terminals crafted from the negative terminal of an alkaline battery will suffice. Thermistor terminals can be fashioned from a nickel strip, 5 mm in length. To ensure a precise fit for all parts, utilize a utility knife to trim them down to size. A crucial note: utilizing a Battery Management Circuit (BMS) is an absolute necessity! The Roomba is designed to utilize NiMH batteries. Fully charged NiMH batteries possess a higher voltage than Li-Ion batteries (19.2V vs 16.8V). When charging with a constant current, the voltage will exceed 16.8 volts, prompting the BMS to disconnect the battery from the Roomba to prevent overcharging. Consequently, the Roomba will display a Charging Error 5. To prevent this, you must add a circuit inside the battery to deceive the Roomba into perceiving high temperature readings when the battery is charged. For more information, refer to the GitHub repository: https://github.com/nickshl/RoombaChargeLimiter