Best answer: Like the Samsung Galaxy Note 10+, the Samsung Galaxy S20 Ultra can charge at 45W under very specific conditions including PPS, PDO, 10V/4.5A speed, and more. Because these specific conditions haven't been used on many phones so far, few third-party chargers reliably charge the S20 Ultra at 45W right now.

Why can't I just use any 45W Power Delivery charger with the S20 Ultra?

Samsung took several extra steps in the way it handles high-speed charging to prevent overheating and long-term battery damage. Unfortunately, those steps are a series of hoops that accessory makers and users like you and me have to jump through when we want to charge our S20 Ultra at top speeds. In order to get 45W charging, your setup needs to have the following:

• PPS (Programmable Power Supply) — this is a subsection of Power Delivery 3.0, and there are few chargers out there to support it so far.
• 10V/4.5A charging speed
• PDO (Power Delivery Objects) — this negotiates the voltage/speed between the charger and the phone. It's what makes the difference between your S20 Ultra getting the more standard 10V/3A and 10V/4.5A from a charger.
• An e-marked USB-C to USB-C cable

Because these specific requirements are only used by a handful of extra-expensive phones, accessory makers have had little reason to support this non-standard charging profile. You'll see a lot of chargers on Amazon that say they're PD 3.0 (PPS2.0), but they still don't support PDO or the 4.5A charging speed and thus, won't get full 45W charging.

I would love to sell you more travel-friendly 45W chargers for the S20 Ultra, really. I'm the kind of nerd who enjoys finding the best quality and best features in a charger, but for the Galaxy Note 10+ and Galaxy S20 Ultra, there's nothing but heartbreak to be found out there right now beyond a few car chargers and power banks. I've yet to come across a 45W non-Samsung wall charger for the Note 10+ that actually hit 45W, and there's been little progress since its launch.

Why 45W won't matter for most of us anyway

Charging a 3,500mAh Note 10+ from empty to full takes 55-58 minutes with the 45W charger while charging the same phone with the 25W charger that comes with the Note 10+ — and with the S20 Ultra — takes 65-70 minutes. The reason for this is that like all chargers, you only get the maximum speed during the first few minutes while the battery is almost empty. As the battery refills, the charging speed gets slower and slower to prevent your phone from overheating. It's also better for the battery long-term.

This variable in speed means that once you reach about 55% charged, you'll see approximately the same charging speeds on the 25W charger and 45W charger. So if you tend to have 40-50% battery left when you plug back in between work and your dinner date, you won't be getting the full benefits of the charger, nor will you see significantly shorter charging times compared to the in-box 25W charger.

You'll see At most a 25-minute difference between the 25W and 45W charger from empty-to-full. That's probably not going to be worth the extra $20-40 for a wall charger.

Where you might see the real benefit of 45W charging is on-the-go, such as during marathon days at a tech conference or rushing around Walt Disney World. In those instances, having a 45W power bank that can get your phone refueled in as short a time as possible could be worth its weight in gold. Like wall chargers, there aren't too many power banks that will charge the Note 10+ and S20 Ultra at 45W, but two models from Elecjet are confirmed to work with it right now: the 10,000mAh Apollo Max and the 20,000mAh PowerPie.

Samsung 45W USB-C Super Fast Charging Wall Charger

If you need the fastest charge you can
The 5,000mAh battery on the Galaxy S20 Ultra can take a while to recharge from empty, and if you're the kind of person who's always on their phone, a 45W charger can let you free yourself from the wall charger as soon as possible.

If you're usually only down to 30-40% when you recharge your phone, the 45W charger will barely be any faster since that full speed is only employed at the beginning of the recharge cycle. In that instance, you can probably stick with the 25W charger that was included in the box with your S20. However, if you want a spare for your gear bag or office desk, you can find it for half the cost of the 45W charger.

Samsung 25W USB-C Super Fast Charging Wall Charger

The standard charger is fine for most folks
This is the charger that comes in the box with the Galaxy S20 Ultra, and for regular users that don't let their Ultra drain all the way, it should be just fine. You'll only really notice the slower speed on full empty-to-full recharges.

As mentioned before, Elecjet offers two USB-C Power Delivery power banks that can charge the S20 Ultra at max speed: a 10,000mAh model that's still limited to Indiegogo and a larger 20,000mAh model that's been out for a while and is available on Amazon. Aside from the vendor difference, the 20,000mA model makes more sense from both a capacity and pricing perspective. The PowerPie is less expensive and can recharge the S20 Ultra four times before it runs dead.

ELECJET PowerPie 20000mAh Power Bank

Ditch your tether as quickly as possible
No one wants to walk around with a cord sticking out of their phone and their backpack. This bank can recharge your S20 Ultra at its maximum speed so that you can get back to seizing the day and taking Space Zoom photos of all the things!