Realistic fast wireless charging speed

[YuanhaoYoung]

I recently bought a fast charger for my car (Rocoren 4-port PD, which supports up to 30W) and a wireless charging phone holder. When I put my phone in the holder, it says Fast Wireless Charging, so the phone can detect the charger supports fast charging. But eventually this changes to Wireless Charging. Using AccuBattery, I can see the wattage varies between 2w and 3w, which seems low. But if I go into settings and turn off Fast Wireless Charging, then the phone takes even longer to charge.

I also tried this with an Anker fast wireless charging stand and got pretty much the same result.

Realistically, should I get closer to 10w or 15w? If not, what should I be getting?

 

[B. Diddy]

At what battery level does the charging rate drop down? Keep in mind that as the battery approaches 100%, charging rates always slow down -- it's the nature of how a battery is charged.

 

[YuanhaoYoung]

It doesn't seem to matter. I've seen this when the level is around 50%. I do have the protect battery setting on, to limit max to 85%.

I forgot to mention that if I connect directly to a fast wired charger, it works great. Very fast at the same battery levels.

 

[B. Diddy]

Does the phone get pretty warm while charging wirelessly? That might also affect charging speeds -- it might automatically drop down to slow charging as a safety measure.

 

[YuanhaoYoung]

I'm not sure. I'll have to check that, although I think it starts off slow even before it's had a chance to warm up. Thanks for the suggestion!

 

[Laura Knotek]

Are you charging more than one device at a time? Which USB port are you using?

Which wireless charger are you using with that USB car charger?

 

[gomezz]

I recently bought a new Anker wireless stand which supports fast charging. But when I tried it with any of my existing USB charger plugs it would not go fast. I then realised I also needed an new USB charger plug to use with it that could deliver the extra power it could accept. From what I could see an S20 only accepts up to 19W anyway and in practise that seems to take about 50% longer to charge than a direct cable.

(I have an older wireless charging stand in the bedroom that does not do fast charging but as that is for overnight charging then not an issue)

 

[YuanhaoYoung]

Are you charging more than one device at a time? Which USB port are you using?

Which wireless charger are you using with that USB car charger?

I'm only charging the one device, and I made sure to use the port marked as 67W/30W.

B. Diddy might be on to something with temperature. This morning when it was cold in the car, I saw much higher wattage, up to 7W-9W range, with the battery at 80 degrees F. In the afternoon, with the battery at 96 degrees, charging seemed slower. Unfortunately, the car is going to be warmer most of the time

 

[B. Diddy]

I'm only charging the one device, and I made sure to use the port marked as 67W/30W.

B. Diddy might be on to something with temperature. This morning when it was cold in the car, I saw much higher wattage, up to 7W-9W range, with the battery at 80 degrees F. In the afternoon, with the battery at 96 degrees, charging seemed slower. Unfortunately, the car is going to be warmer most of the time

Yeah, that may be a safety mechanism. You don't want to be charging a battery at high speed if it's really hot, since that would increase the risk of fire or explosion.

 

[magenta]

the faster Chargers can cause battery to drain faster

 

[B. Diddy]

the faster Chargers can cause battery to drain faster

This is only over time, assuming the fast charging causes the battery to deteriorate a little more quickly over the long run.

 

[YuanhaoYoung]

Thank you to everyone for your input. I've been checking, and the wireless charging does seem to be much faster than it's cold. However, wired fast charging is still faster at the same temperatures. A limitation of wireless charging, I guess. In any case, I'm happy the mystery is solved, and I'm still getting better charging speed than before.

I also turned on battery protect, so it stops charging at 85%. That should protect the battery somewhat.