Nitecore · United States · compact
Exact model: Carbon Battery 6K · Revision: Current 6K model
Product identity · checked 2026-10-07
Manufacturer product image · source
The cylindrical Carbon Battery 6K puts an explicitly rated 21.6Wh into an 88g, 22.8 × 90.4mm body. Its single USB-C input and output are both limited to 10W.
View manufacturer product pageAvailability checked 2026-10-07. Stock can change.
Manufacturer product image · source
BatteryRank review
A very light compact bank for buyers who prioritize a small 88g carry and accept a 10W USB-C ceiling in both directions.
Ratings below are manufacturer-claimed. Open a reading to see its source and check date; derived comparisons are identified separately.
Use and carrying fit
Nitecore lists 88g, IP68, and one USB-C port rated 10W input and output. The product shape is cylindrical rather than a flat phone-pack layout, so the published 22.8 × 90.4mm dimensions are useful when planning pocket or pouch fit.
What changes the choice
The bank is rated at 6,000mAh / 21.6Wh, and Nitecore lists 10W maximum USB-C input and output. That is a much lower power ceiling than the 22.5–30W outputs in the nearby 10,000mAh outdoor models.
Nitecore lists a single USB-C input/output port and does not list a second wired output. Buyers who need simultaneous wired charging should compare a multi-port bank instead.
Before connecting devices
A port’s published maximum and the combined multi-port limit are separate ratings. A device can draw less than the bank’s maximum based on its own requirements and the negotiated charging profile.
The product page lists USB-C input and output at 5V/2A. That is a 10W maximum in either direction, so it is not the choice for fast-refilling the pack or for devices that need a higher USB-C power profile.
Manufacturer documentation
Manufacturer claims link to the dated source used for this exact revision. Watt-hours appear only when the OEM states them explicitly; we do not infer energy from milliamp-hours.
Exact-model questions
Yes. Nitecore specifies 6,000mAh at 3.6V, or 21.6Wh, and separately lists 3,700mAh at 5V as rated output energy. We use the explicit 21.6Wh cell figure for energy-per-weight comparisons.
No. The single USB-C port is listed at 5V/2A for both input and output, which is a 10W ceiling. Check that limit against the source and device you plan to use.
Evidence record
We use manufacturer documentation for the product identity and claims shown on this review.
Checked 2026-10-07
Checked 2026-10-07
Checked 2026-10-07
Review updated 2026-10-07. Ratings are manufacturer claims tied to the cited documents.