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Blog1 min read

How many volts does a phone battery run on?

The lithium-ion batteries in phones usually have a nominal voltage of 3.7 to 3.9 volts; a full battery reaches roughly 4.2 to 4.45 volts depending on the model. A charger supplies 5 volts over USB; with fast charging, the phone and adapter agree on a higher voltage. Volts and mAh together set the energy.

Cep Market Repair TeamIn Kadıköy since 2006
Key points
  • Nominal voltage is usually 3.7–3.9 volts.
  • A full battery reaches roughly 4.2–4.45 volts.
  • Energy (Wh) = mAh × volts ÷ 1000.
  • USB charging is 5 volts; fast charging raises it by agreement.
  • The charging circuit lowers the voltage to suit the battery.

01Voltage in a phone battery

ValueApproximate voltageWhat it means
Nominal voltage3.7–3.9 VThe value on the battery label
Fully charged4.2–4.45 VVaries by model and battery type
DischargedBelow nominalThe phone switches itself off at a set level to protect the battery

The voltage (V) and capacity (mAh or Wh) are written on the battery or its technical sheet.

02Volts, mAh and Wh

The energy a battery holds is voltage multiplied by capacity: Wh = mAh × V ÷ 1000. For example, a 4,000 mAh battery at 3.85 V holds about 15.4 Wh. So at the same mAh, a battery with a higher nominal voltage holds a little more energy. How mAh affects battery life is in phone battery mAh explained.

03The charger’s voltage

  1. Standard USB. The charger supplies 5 volts.
  2. Fast charging. If the phone and adapter are compatible, they agree on a higher voltage; if not, they stay at 5 volts.
  3. Charging circuit. The circuit inside the phone lowers the incoming voltage to what the battery accepts.

The adapter’s amps and watts are covered in iPhone charger amps and watts.

Why it is dangerous is in phone battery shocking risks.

Brand › Model › Repair listChoose your model, ask about the faultSamsung models

04How to get your phone to us

Visit our store

Hasanpaşa Mh. Söğütlüçeşme Cd. No: 192 (opposite the mosque car park), Kadıköy. Monday – Friday 09:00 – 20:30 · Saturday 09:30 – 20:30 · Sunday: Please ask.

Send it by post

Free two-way shipping with our contracted carrier from anywhere in Turkey. Send the device without its case, in a well-protected box, with a note giving your phone number and the fault.

Motorbike courier

Within Istanbul you can send your device by motorbike courier; just send us your address and the fault on WhatsApp.

FAQ

Frequently asked questions

01

How many volts is a phone battery?

The nominal voltage is usually 3.7–3.9 volts; a full battery reaches roughly 4.2–4.45 volts depending on the model.

02

Why does a charger supply 5 volts?

5 volts is the standard USB voltage; the circuit inside the phone lowers it to what the battery accepts.

03

Does fast charging give the battery higher voltage?

The adapter supplies power at a higher voltage; the phone’s charging circuit lowers it to suit the battery.

04

Will a battery replacement delete my data?

Data is usually preserved during a repair; still, you need to back up your data before the repair starts (backups are the customer’s responsibility).

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What our customers say

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Today we had an original battery replacement on our iPhone 14 Pro done by Can, and we thank him very much for his kindness, his speed and his professional support. You can come with no question marks in your mind. I recommend it 👍

Özgür Can K.Customer review · Translated from Turkish
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They replaced the battery of an iPhone 11 in 20 minutes and handed the device back.

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I had the screen and battery of my 14 Pro Max replaced and I am very pleased. Thanks for your work.

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This is the place I have shopped at with endless trust and sincerity for 20 years, since the Cep Market days. I am so glad you are here; Teknoway is the only place for me.

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A company I have known for a long time that helps in every way it can. I definitely recommend dropping by and at least listening to their ideas and advice.

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We had a screen protector fitted, and they gave us gifts I think were worth more than the screen protector. Most of all, thank you for the friendly welcome.

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From our customers’ reviews. All reviews

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