My old Honda Civic's battery drained overnight several times. Since it's a less than 2 year old battery, I suspected there was a parasitic draw in the electric system. They performed a parasitic draw test for the car and didn't find there was such issue. But they found the connection to battery terminals were loose, causing the battery not getting charged very well. So they fixed it, and charged me with a minimum labor cost of $60. A month after driving the car out of their shop, the battery never drains again. I feel they are honest and professional.