If you're REALLY concerned about it, I'd install a 240V (or 208V) socket in your garage, and use a plug-in L2 charger (as mentioned previously, Clipper Creek makes nice ones). Then, if your L2 fails, a phone call and a credit card should get you a new L2 charger in a day or two. It might be quick & free if the old one is under warranty. In the mean time, you can use the L1 charger that came with the car.
If you're REALLY REALLY concerned about it, I'd install a 240V (or 208V) socket in your garage, use a plug-in L2 charger, and have a spare L2 charger on the shelf. That way, if your L2 fails, you just swap it out.
If you're REALLY REALLY concerned about it, I'd install a 240V (or 208V) socket in your garage, use a plug-in L2 charger, and have a spare L2 charger on the shelf. That way, if your L2 fails, you just swap it out.