In South Carolina if your liability insurance is cancelled or expired, you must return your vehicle's license plate and registration to DMV or reinstate your coverage. Otherwise, your driver license and vehicle plate will be suspended and you will be subject to a reinstatement fee of $200 and $5 penalty for each day the vehicle was uninsured or plate(s) was not turned in. The maximum penalty for the first offense is $400 per vehicle.

If your car is inoperable and not being driven but you want to keep the car registered it would appear that you need to keep insurance on the vehicle. If you do not want to operate the vehicle or keep insurance on it you need to inform the SC Department of Motor Vehicles and turn in your license plate and registration. Since you already let the insurance lapse on the vehicle you will want to make certain that you do not have any penalties to pay when you turn in the plates.

Also keep in mind if you are going to donate the car you should check with the charity you are planning to give it to and find out what they require of you. It may be that current registration is needed or at least a way in which for the charity to register the vehicle. If it is the latter, when you turn in the plates ask the DMV if this will be possible for the organization you donate your vehicle to.