The short answer
- Not charging at all: check the pack's own battery, then alignment, then the case.
- Charging slowly: usually heat, a thick or non-magnetic case, or the phone being above 80%.
- Stops at 80%: often normal. Optimised Battery Charging, the charge limit or high temperature can all hold the iPhone at 80%.
- Getting hot: some warmth is normal for wireless charging; real heat means poor alignment or a hot environment.
Nine checks, in order
1. Is the power bank itself charged?
Press the button or look at the indicator. A pack at its last bar may switch off its wireless output early to protect the cell. Recharge it fully with a USB-C cable and try again.
2. Is wireless output switched on?
Many magnetic packs need a button press to start, or switch off automatically when nothing has drawn power for a while. Press the button once after attaching the phone.
3. Are the coils aligned?
The magnet ring should pull the pack to the centre of the phone's back. If the phone has no built-in magnets, such as the iPhone 16e or SE, or the case has no magnetic ring, the pack can sit off centre and charge slowly or not at all.
4. Is the case too thick or not magnetic?
Thick protective cases, metal plates, wallets and cards between the phone and the pack weaken the magnet and the wireless link. Use a slim case with a built-in magnetic ring, and never put cards or metal between the two.
5. Is the phone too warm?
Apple notes that iPhone may limit charging above 80% when the battery gets too warm, and it slows down to protect the battery. Take the phone out of your pocket, stop gaming or navigation for a few minutes, and keep it out of direct sun.
6. Is the iPhone holding at 80% on purpose?
Optimised Battery Charging and, on iPhone 15 and later, a charge limit of 80–95% can stop charging before 100%. Check Settings, Battery, Charging. This is a feature, not a fault.
7. Is the pack charging itself at the same time?
With pass-through charging, a pack plugged into the wall splits power between itself and the phone. Wireless output can be lower until the pack is full.
8. Are the cable and adapter good enough?
When you charge the phone by cable from the pack, a damaged or low-rated cable limits the speed. Try another USB-C cable that supports fast charging.
9. Restart and update.
A restart of the iPhone clears occasional charging glitches. Keep iOS up to date, as charging behaviour is sometimes adjusted in updates.
What is normal
| What you see | Usually |
|---|---|
| Pack and phone feel warm | Normal for wireless charging |
| Charging pauses at 80% | Normal: Optimised Battery Charging, charge limit or temperature |
| Speed drops after 20–30 minutes | Normal: heat management |
| Pack adds less than its rating suggests | Normal: conversion and coil losses |
| Pack is too hot to hold, swells or smells | Not normal: stop using it |
Wireless charging always loses some energy as heat, which is why a 5,000 mAh pack adds well under a full 5,000 mAh to a phone. We explain the numbers in how much a battery case really charges an iPhone and in our guide to testing a power bank's real capacity.
When the pack is at fault
If the pack does not charge any phone with a slim magnetic case, will not recharge itself from a known good adapter, or loses charge quickly while unused, the cell or the electronics may be faulty. Stop using a pack that swells, smells or gets very hot, and contact the seller. Do not fly with a damaged power bank.
For resellers, these checks also make a good first-line support script, and they reduce returns from customers whose phone was simply in a thick case or holding at 80%.
Frequently asked questions
Why does my magnetic power bank only charge my iPhone to 80%?
Usually because of Optimised Battery Charging, a charge limit set on iPhone 15 or later, or the phone being too warm. None of these is a fault in the power bank.
Does a phone case stop a magnetic power bank from working?
A thick or non-magnetic case can weaken the magnet and the wireless link. Use a slim case with a built-in magnetic ring.
Is it normal for a magnetic power bank to get warm?
Yes, some warmth is normal for wireless charging. If it becomes too hot to hold, remove it and let both devices cool down.
Why does my power bank charge slower than advertised?
Advertised wireless output is a maximum. Heat, alignment, the case and the phone's own charging control all reduce the real speed.