A new J.D. Power study once again confirmed that most electric-car drivers rely primarily on home charging, while also offering some insight into customer satisfaction with different types of charging equipment.

Of EV owners surveyed, 88% said they charged their cars at home "often" or "always," according to the inaugural J.D. Power U.S. Electric Vehicle Experience Home Charging Study.

The study looked at three types of home charging: Level 1 portable, Level 2 portable, and Level 2 permanently-mounted charging stations. Owners who installed a permanent Level 2 station had the highest level of satisfaction, with a score of 749 points out of a possible 1,000 points.

That score was based on eight factors: price, cord length, size of the charging station, ease of winding/storing the cord, cost of charging, charging speed, ease of use, and reliability. Overall satisfaction among owners of portable Level 2 stations was fairly close to the permanently-mounted Level 2 stations, at 741 points, but Level 1 charging was further behind, with a score of 574 points.

That's partly down to charging speed, according to J.D. Power. Despite knowing that charging would be slower than Level 2 stations, owners of Level 1 charging stations were very dissatisfied with speed, the study said.

Clipper Creek HCS-D50 in use

Clipper Creek HCS-D50 in use

We've found that mobile Level 2 charging stations are really only worth considering for short-term renters with access to a 240-volt outlet. It's also possible to get more flexibility with a splitter that allows a portable Level 2 charging station to share an existing household 240-volt circuit.

On the other hand, owners of Level 2 permanent charging stations reported high levels of issues, with 29% reporting that their charging stations stopped working or needed repairs at some point, and 22% reporting wifi issues. Tesla ranked highest among manufacturers of Level 2 permanent stations, with a score of 798 points, compared to an average of 749 points for the segment.

The study also showed that satisfaction is related to something completely out of the control of automakers and charging equipment manufacturers: the cost of electricity.

High electricity costs caused lower levels of satisfaction among owners in the Northeast, according to J.D. Power. However, the study also found that utility-run programs, such as EV-only rate plans, were underutilized. Customers can also qualify for incentives to offset the purchase of a charging station, depending on the state, but may not be aware of that.

If you're considering a home charging station, we've got a guide that covers the basics.