The expansion battery register

An expansion battery is usually the second-biggest purchase in a power-station ecosystem — and the one where spec pages say the least. Two questions decide most of its real-world value, and we answer them explicitly for every pack we track:

• Does it work as a battery on its own? Some packs carry their own USB or 12V outputs and function as a standalone power bank. Others are link-port only: no outputs of their own, usable solely while connected to their host station.
• Can it recharge without the station? Some packs accept solar, AC, or car input directly; others can only be refilled through the host station.

Neither design is wrong — a link-port pack is often lighter and cheaper per Wh — but the difference matters if you pictured, say, leaving the pack at a campsite while the station rides in the truck. Verdicts below come from manufacturer documentation verified per model; where we could not verify, the table says unknown rather than guessing. Cycle-life spreads in this table are wide (500–6,500 rated cycles) and worth as much attention as price. How we verify.