iPhone XS Max Fast charge of iPhone XS Max issue

[duckson]

I’ve got a Ravpower power bank that has a USB C output/input but I’m not sure it’s working correctly with my XS Max.
Using a USB C to lightning cable (2 different ones actually, Amazon and Choetech) it seems to put it on fast charge (I get a double charging bong notification) and the light illuminates on the power bank but after 10-15 seconds it goes out. Wait another short while and I get a charging bong again and the light illuminates (note all the while the phone is indicating it’s being charged at least at a standard rate). The light also goes off and on with my sons iPad Pro 10.5 (no bings, assume that’s only an iPhone thing?).

Phone percentage was about 54%, my Anker fast wall charger puts it into fast charge and it stays there.

 

[BuggyGT]

The double beeps are no longer accurate way of knowing if it is fast charging or not, on my iPhone 11 Pro I sometimes get the double beep or sometimes I dont so its not reliable. Without using a USB power meter the only way you can really tell is time it yourself. You can try this, when your phone is down to 10% or so battery life plug it in to charge and time roughly how long it takes to charge to 50% it should take about 20 to 25 minutes.

Here is a chart below compared to the 5w charger, for example in 30 minutes the slow 5w charging only charged 16% of the battery.

 

[duckson]

Thanks, 10% to 50% took 25 minutes so it seems it’s as it should be!