Google Pixel 7a charging test: Running a little too hot

Google doesn’t provide a charger in the box with the new Pixel 7a, so you’ll have to pick up a compatible third-party charger. Before you do that though, you’ll want to learn more about how the Pixel 7a charges, what specifications it uses, and how long it takes to fill up. We tested the phone to bring you everything you need to know.

How quickly does the Pixel 7a charge?

To test the phone’s charging times and capabilities, we grabbed the official Google 30W USB-C Power Charger ($25 at Google) and the second generation Pixel Stand ($79 at Amazon) for wireless capabilities.

Google’s charger supports USB Power Delivery PPS to fast charge the Pixel 7 series but the Pixel 7a defaults to the standard USB Power Delivery protocol. It pulls 18W (9V, 2A) maximum from this plug, so you can buy plenty of low-power third-party alternatives and still power the 7a without issue.

At 18W, the Pixel 7a takes one hour and 46 minutes to full, which is pretty slow. Hitting 25% takes 16 minutes, getting the battery to halfway takes 36 minutes, and making it to 75% a rather agonizing full hour. As you can see from the graph above, the tail end of the charging process is by far the slowest portion, but the phone isn’t quick to top up in short bursts either.

It’s even slower than the Pixel 7, which features a similarly sized 4,355mAh battery. That might be expected given that it supports but faster marginally faster 20W USB PD PPS charging, but we saw the same charge time when using 18W USB PD. And not just to full charge either; the Pixel 7 hit the 50% and 75% milestones several minutes faster as well. It appears that charging temperatures might have something to do with it.

Why does the Pixel 7a battery charge slowly?

Even if you’ve picked out the correct phone charger, the Pixel 7a takes quite a long time to charge compared to other phones. This is because 18W is already quite a low power level, and it isn’t even used for the whole charging cycle. The latter stages charge at 11W before declining below 5W to finish topping up the battery. Furthermore, Google’s charging algorithm is temperature sensitive, aiming to keep the cell below 40°C by reducing power further.

We can see this clearly in the chart below. The Pixel 7a sustains 18W of power for a decent portion of the early charging cycle when the device is cool (starting unused at 20°C). But once temperatures approach 37°C, the Pixel 7a throttles back the charging power down to 14W and later just 11W until temperatures have declined. When this happens, it adds several minutes to the phone’s already slow overall charge time. We observed it taking just over two hours to charge the phone up with a slightly warmer starting temperature, and the phone becomes quite hot while charging either way.

This temperature issue fits our observed pattern of slower charging in the mid to late portions of the charging cycle compared to the Pixel 7, which does not exhibit the same throttling issues when using 20W or 18W charging. The exact reason for this isn’t completely clear. Still, it’s possible that the Pixel 7a’s chassis cannot dissipate heat at the same rate as the Pixel 7 series or that Google is cautious about this (cheaper?) battery’s sensitivity to higher temperatures.

This also makes sense in the context of the Pixel 7’s conservative low-power wireless charging capabilities. It takes the Pixel 7a over 3 hours to reach full charge on the Pixel Stand (2nd Gen) due to its lackluster 7.5W charging power level. While wireless charging is a welcome addition, it’s painfully slow and unsuitable for topping up your phone quickly.

Google’s Pixel series has always been more sluggish to charge than its competitors, and the Pixel 7a is no different. The good news is that it’s straightforward to find compatible USB Power Delivery and Qi wireless products that meet the phone’s conservative power needs. The downside is that the phone appears bound by temperature constraints that make charging even slower than expected in certain conditions. If you think you’ll need to top your phone up in a hurry, picking the Pixel 7 or Pixel 7 Pro will be a better option than the budget model.