$7900 seems very high for a 2011, even if an SL. I would strongly agree with @rogersleaf’s comments and suggest you do the following:
1- verify if vehicle qualified for a replacement battery from Nissan, and if the vehicle actually got it. This is a PLUS.
2- verify if vehicle has lived in an “unfriendly” (hot) climate at any time in the last 8 years. This is a NEGATIVE.
3- verify if vehicle has a QuickCharge port for DC L3 charging. This is NEUTRAL if present, an big NEGATIVE if not.
4- buy a licensed copy of LeafSpyPro (~$20), and a recommended OBDII adapter (see other threads for latest recommendations. This investment will likely be under $50 and will show you before you buy the existing traction battery’s state of health. This is key to the value of the car. Better health = more value = higher price, but worth it. And the reverse is true.
5- Get a Carfax report, or ask to see the owner’s report if done recently. Obviously any accidents, salvage title, etc., will make the car worth less.
6- Check out edmunds.com and kbb.com for their pricing and guaranteed prices are. These may vary across the nation but give an idea of value.
7- As for any vehicle, check out tire condition. At 78,000 miles, you may be looking at soon purchasing the 3rd set of tires...a not insignificant expense.
8- Ask to see receipts for any work done such as the recommended biannual brake fluid changes and annual cabin air filter changes. Not necessarily critical to the purchase, but again you may have to do these with added expense to you. Same for the 3 different sized wiper blades.
I own a 2012 SL purchased new and in excellent condition but with original battery (didn’t qualify for Nissan replacement). Even in top condition (no accidents, very low mileage, detailed frequently, etc.) it would not be worth what your owner is asking. So:
9- Assuming all of the best cases for the items above, try to negotiate a MUCH better price, perhaps in the $5K-$6K range. Any negatives further reduce the cost.
Sadly, the original 2011-2012 LEAFs are not collectors items and their value, with the hugely decreasing battery capacity, has plummeted. The ugly truth is that a 2011 LEAF is not just an 8-year-old car, but an 8-year-old car with half the “gas tank” gone.
Nissan 2012 LEAF SL Super Black
13,100 miles, 10 bars showing, 72.35% SOH, 47.46 Ahr
Tesla Model 3 - Basic Black | Long Range | Premium Upgrade Package | Extended AutoPilot | Full Self-Driving
Delivered: July 19, 2018 | 6,200 miles