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: Switch off and unplug the mains before removing the clips to avoid sparks and explosive gas risks. Pros:
Disconnect the car's battery terminals from the vehicle, starting with the negative (-) black cable. This isolates the battery and protects your vehicle's sensitive alternator and ECU from potential electrical spikes. selmarturbo4batterychargerinstructions link
You can find the official PDF manual for the Schumacher 4 Amp Turbo Speed Charge models here: : Switch off and unplug the mains before