Its been another bad week for Tesla shares so far. After closing down again yesterday, as of the time of this writing, TSLA shares are down over 5% in early morning trading on Tuesday. The stocks decline this week comes after the company shed nearly 15% of its value in a single day last week.Much of Teslas recent stock declines have been attributed to the public souring of the company as its CEO, Elon Musk, has become increasingly involved in politics in both America and Europe. Since Musks political engagements, including his role in the Department of Government Efficiency (DOGE) in the United States and his support of the far-right party Alternative for Germany (AfD) in the EU, Tesla sales have slumped in several markets.While todays decline could be a continuation of the worry over the brands declining image in the eyes of consumers, there are also three other possible reasons why TSLA shares may be heading lower today.Chinese rival BYD unveils new charging technologyChina is Teslas largest market outside of the United States. But the electric vehicle maker faces stiffer competition there than it does at home. And Teslas lead rival in ChinaBYDhas now announced a new charging platform that makes Teslas superchargers look archaic.As CNBC reports, BYD has announced its Super e-Platform charging technology, which the company says can deliver peak charging speeds of 1,000 kilowatts, allowing a car to be charged up enough to go about 249 miles (400 kilometers) in just five minutes of charging.To put that into perspective, Teslas Superchargers have a peak charging rate of just 500 kilowatts. It takes 15 minutes for a Supercharger to give a vehicle enough range to travel around 168 miles (about 270 kilometers).If BYDs claims hold, the companys Super e-Platform will be a serious blow to Tesla and its Superchargers. It could be enough to make many in China opt for a BYD over a Tesla. If they do, Tesla sales in the country could continue to decline.Cybertruck quality concernsAnother issue that may be negatively impacting Tesla stock this week is reports on social media that the companys beleaguered Cybertrucks have yet another problem.As GuruFocus reports, videos of Cybertrucks have gone viral on social media recently, showing that the vehicles metal panels seem to be detaching.The worry is that if these quality issues are not addressed, it could affect sales of the vehicle.Tesla gets lower price targetFinally, on Tuesday, RBC Capital Marketsa traditional Tesla bullrevised its price target on TSLA. While RBC still maintains a buy rating on the stock, the firm lowered its price target on TSLA shares from $440 to $320, reports MarketWatch.RBC said it made its revision after it slashed its estimate for what Tesla will charge each month for its self-driving car software. RBC had originally thought Tesla would charge $100 a month, but now thinks a $50 price is more likely.The firm also cut its projection for Teslas share of the robotaxi market in Europe and China. It had expected around a 20% share of the markets there, but now says it expects Tesla to have a 10% share.Tesla shares are down 44% year-to-dateAs of the time of this writing, TSLA shares are currently down another 5.81% in early market trading to $224.19 per share.That means Tesla shares have now fallen over 44% since the beginning of 2025. Tesla shares peaked in December at over $488 apiece.While Tesla shares have crashed in 2025, they are still up about 29% over the past 12 months.