Power bank won't charge my phone, or charges it really slowly: how to fix it
The power bank's lights are on, the cable is plugged in, and the phone either does nothing, charges for a few seconds and stops, or crawls up 1% every few minutes. Most of the time the bank is fine: something between it and the phone isn't agreeing.
1. The cable (the usual culprit)
Charging cables wear out at the ends long before they look broken, and many cheap cables only have the thin wires needed for slow charging. Signs it's the cable: it works at one angle but not another, it charges slowly everywhere, or it gets warm at the plug. Swap in the cable that came with a recent phone or a known-good one before blaming anything else.
- USB-A to USB-C or Lightning cables can work for slow charging, but most fast charging needs USB-C at the power bank end.
- USB-C to USB-C cables are normally rated for 3 A (60 W), which is plenty for any phone. Laptops above 60 W need a 5 A (100 W or 240 W) cable.
- A cable that only charges and never shows the phone to a computer may be a charge-only cable. That's fine for charging, but it hints it's a basic one.
2. The port and the fast-charging “language”
Fast charging isn't automatic: the phone and the bank first agree how much voltage and current to use. If they don't speak the same standard, they fall back to plain, slow 5 V charging.
| Standard | Usually on | Who uses it |
|---|---|---|
| USB-C Power Delivery (PD) | USB-C ports | iPhones (8 and later), Pixels, most Android phones, tablets, laptops |
| PD with PPS | USB-C ports that say PPS | Samsung “Super Fast Charging” and some other Android phones |
| Quick Charge (QC) | Often USB-A ports, sometimes USB-C | Some, mostly older, Android phones |
| Plain USB (5 V) | Any port | Everything, slowly |
So the fix is often just moving the cable to the bank's USB-C port and using a USB-C cable. Look for “PD” and a wattage (18 W, 20 W, 30 W) printed by the port. A phone that wants 20 W and gets 10 W will still charge, about half as fast.
Plugging two devices into one bank at once often drops every port to slow charging. Charge one at a time if speed matters.
3. It charges for a few seconds, then stops
Most power banks switch themselves off when the current drawn falls below a small amount, so they don't drain themselves while sitting in a bag. Earbuds, smartwatches, fitness bands and some phones that are nearly full draw less than that, so the bank decides nothing is plugged in and turns off.
- Look for a low-current or trickle-charge mode in the manual. On many banks it's a double press or a long press of the button.
- Charge small gadgets from a wall charger instead, or plug them in while the bank is also charging a phone.
- If a phone does this, check it isn't already full or holding its charge at 80% on purpose (see below).
4. Charge left, temperature and protections
- Is the bank actually charged? Some show one light right up until empty. Charge it fully with its own cable and try again.
- Cold. Phones pause or slow charging when their battery is too cold, to avoid lithium plating. Warm the phone to room temperature first (see charging in the cold).
- Heat. A phone that's hot from the sun, a game or a thick case slows or pauses charging until it cools (see phone gets hot while charging).
- Pass-through. Charging the bank and a phone from it at the same time is slower, and some banks don't support it at all.
- Optimised charging. iPhones and many Android phones deliberately hold at 80% for a while, or permanently if you've set an 80% limit. That's a setting, not a fault.
5. The phone's port
Pocket lint packs into charging ports and stops the plug going all the way in. If the cable feels loose or only works when pushed, power the phone off and gently scrape the port out with a wooden toothpick or a plastic flosser. Avoid metal and don't blow into it.
6. It's charging, just slower than the phone uses power
Gaming, navigation with the screen at full brightness, hotspot sharing and video calls can use as much power as a slow bank supplies, so the percentage barely moves. Close those apps or turn on low power mode while charging.
Also check how many charges your bank should give in the first place: a 10,000 mAh bank gives about 1.4 full charges of a typical modern phone, not two or three. The power bank calculator works it out for your own bank, including how long the bank takes to refill.
When to give up on the bank
Stop using a power bank that is swollen, rattles, smells of burning or solvent, or gets hot while sitting idle. Don't throw it in the bin: take it to a battery recycling point. A bank that has simply lost capacity after a few hundred cycles is worn out rather than dangerous.
Related
Cable loose or only charges at an angle · Phone says moisture detected and won't charge · Phone gets hot while charging · Laptop plugged in but not charging · Power bank mAh vs Wh · Is it bad to charge a phone in the cold? · Why phones drain fast in the car or on the train · USB-C cables explained: which one charges a laptop · Why phones stop at 80% overnight · Earbuds or case not charging · Interactive: why phones and computers get hot
Questions
Why does my power bank stop charging after a few seconds?
It thinks nothing is connected because the device draws very little current, which is common with earbuds, watches and nearly-full phones. Use its low-current or trickle mode, or charge small gadgets from a wall charger.
Why won't my power bank fast-charge my iPhone?
iPhones fast-charge only over USB-C Power Delivery at about 20 W or more. Use the bank's USB-C PD port with a USB-C cable. Quick Charge on a USB-A port charges an iPhone at normal speed.
Can a cable make a power bank charge slowly?
Yes. Worn or basic cables are the most common cause of slow or intermittent charging. Try a known-good USB-C cable before anything else.
What is the difference between PD and QC?
They are two different ways for a charger and a phone to agree on a higher voltage. USB-C Power Delivery is the common standard used by iPhones, most Android phones and laptops. Quick Charge is Qualcomm's older system used by some Android phones.
Why is my power bank charging my phone so slowly while I use it?
Games, navigation, video calls and a bright screen can use about as much power as a slow bank supplies. Close them or use low power mode while charging.
Published · updated .