What voltage is a lightning charger?
Lightning bolts carry enormous voltages—typically tens of millions to a billion volts. Chargers using Apple's Lightning connector do not have a single fixed voltage; they negotiate via USB Power Delivery and commonly operate at 5V, 9V, 15V, or 20V, delivering about 18–20 watts when fast-charging an iPhone.
In this article, we distinguish between two meanings of the phrase "lightning charger": the natural electrical discharge of a storm and the consumer charging accessories that connect via Apple's Lightning port. The sections below explain the voltage ranges, how charging works, and what to expect in practice.
Lightning as a natural phenomenon
Typical voltage ranges
Lightning is a brief, stochastic discharge in which the voltage along the conducting channel is enormous and hard to pin down precisely. Estimates commonly place peak voltages in the range of about 100 million to 1 billion volts, with wide variation depending on storm conditions and the length of the channel. The current carried by a strike is usually tens of kiloamps, and energy release depends on duration and channel resistance. In short, voltage is extremely high but not a fixed value.
Key facts about natural lightning voltages include:
- Typical voltages are in the tens of millions to over a billion volts (rough estimates).
- The voltage is highly variable and short-lived, lasting microseconds to milliseconds.
- The current often ranges from about 10 kA to 100 kA or more, depending on the strike.
- Voltage can be influenced by distance, cloud charge, and atmospheric conditions, making precise figures elusive.
These numbers help illustrate why lightning is both immensely powerful and inherently unpredictable. Even with modern measurement techniques, a single strike can show wide variance in voltage and current from one event to the next.
Lightning connectors and charging voltages
How USB Power Delivery negotiates voltage
When a charger uses the Apple Lightning connector for charging, the device does not rely on a fixed output voltage. Instead, the charger and the device negotiate via USB Power Delivery (PD) to determine a safe, optimal voltage and current. The common PD voltage levels are 5V, 9V, 15V, and 20V, with the exact choice depending on the charger capabilities and the device's acceptance profile.
For iPhones and other devices that support fast charging with Lightning, typical practical outcomes are around 18–20 watts of power when using a compatible USB-C PD charger (for example, an 18W or 20W adapter) with a Lightning-to-USB-C or USB-C-to-Lightning cable. The actual voltage delivered at the phone will be one of the PD levels the handset negotiates (most often 9V for fast charging), and the current adapts accordingly.
In short, a Lightning-based charger does not have a single fixed voltage; it adapts based on negotiation, hardware capability, and cable type.
Summary
The phrase "lightning charger" spans two realities: the extreme voltages of natural lightning and the capped, negotiated voltages of modern USB Power Delivery charging using Apple’s Lightning port. Natural lightning voltages are vast and highly variable, while Lightning charging leverages standards to deliver modest but fast power, typically up to around 18–20W via 9V or similar PD profiles. Always treat lightning as dangerous and rely on certified charging equipment for everyday use.
Is the Apple 20W charger 5V or 9V?
20W can provide a maximum of either 5V3A or 9V2.
Is USB-C 5V or 12V?
USB-C power supplies always support 5 V and some are limited to that, but support for higher voltages is where it's at. The usual voltage steps of USB-C are 5 V, 9 V, 15 V and 20 V ; 12V support is optional and is more of a convention.
What voltage is a Lightning cable?
5 Volts DC
Apple's power rating for its Lightning cable is 5 Volts DC carrying 1.8 Amps of current equaling 9 Watts of power.
How many volts is an Apple USB-C charger?
Apple 20W USB-C power adapter
Line Voltage: 100 to 240 VAC. Output Voltage/Current: 9 VDC/2.2 A.
