We've reported several times about Tesla repair specialist Gruber Motors. The family-owned Phoenix-based company specializes in restoring and repairing old Tesla Roadsters, though it can fix other Tesla vehicles as well.

Not long ago, we told you about Gruber's new Tesla Model S battery pack repair process. Essentially, Gruber can analyze a battery pack, figure out if there are bad cells, replace them, and have you back in action. The company did just that with a used Model S, saving the used buyer some $15,000 or more.

A used 2014 Model S goes for around $30,000 or more. However, due to the bad battery pack, the buyer picked it up for just $10,000. It was going to cost about $20,000 to have Tesla replace the car's battery pack. Gruber was able to fix it for just $5,000. In fact, the issue was just one single faulty battery cell out of over 7,000.

Once we learned that the single cell repair/replacement cost a whopping $5,000, we were a bit shocked. If you bought an expensive Tesla and then had to drop another $5,000 for a cell repair, you certainly wouldn't be happy. However, it's a very involved process, which you can see in the video below.

For people with older Teslas, or for people buying cheap Teslas on the used market, this seems like a really good option. Battery pack replacements aren't cheap. While Tesla was going to replace the pack in this car for $20,000, that's not the case in all situations.

Interestingly, with Tesla's eight-year/120,000-mile battery warranty, you might assume the pack would have been covered and replaced for free. However, that wasn't the case. We're not sure why, but this is not uncommon with warranties. Much like insurance coverage, the devil is often in the details.

Got a tip for us? Email: tips@insideevs.com