if the car isn't paid off, don't do it. If it is paid off, consider these things;
Q1. what is your net monthly income? (after taxes, medical/dental/vision insurance)
A1. if you can't even afford the payment, don't get it.
Q2. how much is left every month after expenditures (food, gas, insurance, utility bills, rent, etc..) & supercharger payment?
A2. if it's not enough to keep doing the things you like to do, movies, dates, travelling, etc.. don't get it.
Q3. can you pay off the superchager within the 1 year interest free period?
A3. if you can't do it, don't get it.
Q4. are you using your credit or your dads?
A4. if you're going to use his, don't do it.
My opinion;
you would be better served by using the funds, being saved or will save, for the supercharger to pay off your bad debts. if you plan on buying something of significant cost (car, house, etc..) within the next 7-10 years, you should build your credit back up. You will save much more money in the long run by having a higher credit score & lower interest rates for purchases.