Google explains the tradeoffs that led to Pixel 6’s slow charging complaints

Google has responded to allegations that the Pixel 6 and Pixel 6 Pro don’t charge as fast as some have expected, confirming that their charging speeds are a deliberate tradeoff for better battery life. It follows a report from Android Authority which found that the phones’ maximum power draw was around 22W, well short of the 30W that Google’s latest USB-C charging brick is technically capable of.

Writing in a community support post, a spokesperson for Google confirmed that the maximum power draw of the Pixel 6 and Pixel 6 Pro are 21W and 23W respectively when used with its 30W USB-C charging brick. They added that charging speeds also decrease as the phones’ batteries fill up to preserve their longevity.

In their post, they note that these figures are the inevitable results of battery tradeoffs. “A battery can be designed for high energy density, or for fast charging power capability, which requires trading off capacity to minimize battery degradation,” says the spokesperson. In other words, a phone can offer long battery life, or fast charging, but it can’t do both at the same time. So, Google prioritized a longer battery life and designed the phones to draw a more modest amount of power when charging.

This tracks with what we observed in our review of the two phones:

”Even if you do use a powerful enough charger, neither phone charges particularly quickly. Google aggressively slows down charging once it’s past 80 percent to preserve the battery cells’ longevity, and since these batteries are so large, getting to a full charge can take a long time. Fortunately, thanks to the long battery life, you will likely only have to charge when you’re sleeping anyway.”

Although Google’s support documents never explicitly state the charging speeds of the new phones, their compatibility with Google’s 30W charging brick (sold separately) was taken by many to mean that their real-world maximum charging speeds would approach the 30W level, and would be far faster than the 18W charging supported by the Pixel 5. But in reality, Android Authority’s report found that the actual power draw of both phones peaks at 22W and averages around 13W over the course of a full cycle.

The effect of this is that the phones charge far slower than you might expect, with Android Authority finding that the Pixel 6 Pro takes almost two hours to reach a full charge. That’s 49 minutes slower than Samsung’s Galaxy S21 Ultra, which has a similarly-sized battery but is only advertised with 25W fast charging speeds. In fact, Google’s power draw is so conservative that its 30W charger only fully charges a Pixel 6 Pro 10 minutes faster than its old 18W charger.

Google never claimed that the phones charge at 30W. Instead, it advertised the amount of time it takes to get from 0 to 50 and 80 percent when charged using its 30W charger — 30 minutes and around an hour, respectively. This is in line with what Android Authority found in its tests.

As well as charging speeds, Google also recently clarified that the seemingly sluggish performance of the phones’ fingerprint scanner is because of their “enhanced security algorithms.” It later released an update containing “some fingerprint sensor performance improvements,” although the improvements it delivered appeared to be minimal in practice.