A battery supply issue may be the reason for Tesla's dip in California.

A battery supply issue appears to have cost Tesla sales in the important California market. Registrations of Tesla vehicles in the Golden State fell by about 24 percent in April, new data shows.

According to registration data from IHS Markit, Tesla registrations in California fell by about 24 percent in April compared to the same month in 2016. April is the latest month data has been compiled for.

Although a 24 percent decline in registrations in one of Tesla's best markets could be viewed as a red flag for the company's outlook, a battery supply issue may explain the sudden dip. Tesla explained at the time of its Q2 sales report that a now-resolved battery supply issue hampered the automaker's overall deliveries.

"If Tesla had an issue with its production for the month, that could explain" the drop in registrations, IHS analyst Stephanie Brinley told Reuters.

However, it's possible that there are other factors at play. Tesla's Model S sedan is now five-years old, so some of its shine as a hot fashion item could be wearing off. Tesla is also preparing to launch a new Model 3 sedan (pictured), which buyers could be waiting to purchase.

So far this year Tesla has delivered 47,100 vehicles worldwide.