Charging speed comparison and practical implications

When it comes to choosing a smartphone, it isn’t just battery size that matters but also how quickly the battery recharges. In this comparison we look at how the Redmi 15 measures up on charging time versus a relevant rival, to help UK buyers assess how “fast enough” is for their needs.

The Redmi 15 comes equipped with a 7,000mAh battery and supports 33W wired fast charging. While many premium phones now offer 65W or more, at its price this is a strong specification. However, real-world full-charge times are estimated closer to around 1.5 to 2 hours, due to the large cell size and budget charging architecture. For everyday UK use—overnight charging or top-ups between tasks—this is ample.

We compare this to a typical “budget flagship” rival such as the Samsung Galaxy A55, which uses a smaller battery (~5,000mAh) and supports around 25W charging according to UK specs. In testing the Galaxy A55 took approximately 1 hour and 24 minutes to reach full charge. While that number sounds lower, the smaller battery means less total energy to refill, and the charging curve is not necessarily faster in early minutes.

Putting the specs side by side: Redmi 15 (~7,000mAh + 33W) vs Galaxy A55 (~5,000mAh + 25W) implies the Redmi should recharge slightly slower due to larger capacity even with higher wattage. Yet the spending difference also means the Redmi offers longer endurance and, in practice, good value charging speed for its segment.

What does this mean for UK buyers? If you regularly find yourself needing a quick top-up before heading out, you’ll find the Redmi acceptable though not ultra-fast. If you plug in at home or overnight, the difference becomes negligible. For heavy gamers or professionals who stop everything to charge quickly, a model with 45W+ might be preferable—but that usually costs significantly more.

In practical terms: if you plug in your Redmi 15 after arriving home and allow 60-90 minutes while doing other tasks, you’ll likely reach 70-80% charge, which is enough for the next part of your day. If you start very low (e.g., <10%) it may take up to 2 hours to reach 100%. The rival may finish sooner, but you’re comparing different class phones and cost brackets.

The takeaway: for its price and battery size, the Redmi 15 delivers good charge speed, especially when balanced against cost and endurance. It may not match flagship sprint charging, but for typical everyday use and budget-focused users it is more than adequate. If you prioritise ultra-fast charging and are willing to pay more, you might explore higher mid-range options, but if your main goal is a strong battery and reliable everyday speed for less money, the Redmi stands out.