Elon Musk says he's going to spend his 48th birthday trying to fix one of Tesla's biggest weaknesses

Tesla CEO Elon Musk said on Twitter that he plans to spend June 28th — his 48th birthday — working on “global logistics.”

Earlier this week, Musk wrote to Tesla employees emphasising the importance of delivering cars to customers by the end of Q2 2019.

He has shunned birthday celebrations in the past, saying that he spent his birthday in 2018 alone with “no friends.”

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Tesla CEO Elon Musk said he will spend his upcoming birthday working on one of the challenges the company has struggled most with — logistics.

Musk turns 48 on Friday, and was asked on Twitter how he plans to spend his birthday. His answer gave an insight into Musk's famed work ethic, which has included work-heavy birthdays before.

“Any big birthday plans？ Or just relaxing w/ family？” — a Twitter user named Reagan Beck asked him.

“Working on Tesla global logistics,” Musk replied.

Tweet Embed: //twitter.com/mims/statuses/1143688793901424640？ref_src=twsrc%5Etfw Working on Tesla global logistics

“You need time off too, don't you？ (Yesss... even you),” Beck then asked.

Musk replied with :(.

Read more: Tesla is reportedly trying to make its own battery cells as its relationship with Panasonic becomes more tense

In the second quarter, Tesla looks set to break its record for the number of vehicles delivered in one quarter, beating the 90,700 vehicles delivered in the final three months of 2018.

Whether or not it does will likely come down to the strength of the company's logistics operation, Musk said in an email to Tesla employees, as reported by Business Insider on Tuesday.

“Logistics and final delivery are extremely important,” Musk wrote.

Particularly he said that the company could succeed by shuffling around orders and stock to get to customers by the end of the quarter, which is Sunday June 30.

Musk wrote the trick was “finding demand for vehicle variants that are available locally, but can't reach people who ordered that variant before end of quarter.”

Tesla blamed problems around its logistics and delivery operations for disappointing car delivery figures in the first quarter of 2019.

Read more: Elon Musk fell off Glassdoor's ranking of the top 100 CEOs after making the top-10 in 2017

It is not the first time Musk has devoted his birthday to Tesla.

Last year, in an interview with the New York Times, Musk said that he spent the entirety of his 47th birthday at Tesla's offices, overseeing the delayed production on the company's Model 3 sedan.

“All night — no friends, nothing,” he said.