Charmast Portable Charger Review: The $21 Power Bank With Built-In Cables

Verdict: Worth it

Charging your phone on the go is easy. Having the right cable with you is the hard part. The Charmast Portable Charger solves that with four cables built straight into a slim 10,000mAh body — USB-C, Lightning, microUSB, plus the pack’s own USB-A recharge cable. At around $21 (often marked down from $29.99), with a 4.5-star average across more than 18,000 buyer ratings and a #2 spot in Amazon’s portable power bank category, it’s the rare budget gadget where the reviews match the promise.

Why we noticed it

Built-in-cable power banks keep showing up in deal roundups — including an October Prime Day tech roundup just days ago — and this one has real marketplace traction behind it: Amazon’s Choice placement and a sustained #2 best-seller rank in portable power banks. The appeal is obvious the first time your phone hits 5% in an airport and the only cable in your bag is the wrong one.

What it does

It’s a 10,000mAh slim power bank (about 8.5 oz) with 4 built-in cables: USB-C, Lightning, and microUSB outputs plus a USB-A cable that recharges the pack itself. Three extra inputs/outputs bring the total to up to 6 devices at once, and it supports 3A fast charging. An LED digital display shows the remaining charge, it recharges fully in about 4.5 hours, it’s TSA/airline-safe, and it ships with a carry pouch in six colors.

What we like

• No cable hunting. The built-in cables solve the #1 annoyance with power banks — the dead cable drawer shuffle before every trip.
• Serious value. ~$21 for 10,000mAh with built-in cables and ~20K ratings is far cheaper than Anker’s equivalent bank at ~$50.
• Charges the whole family. USB-C, Lightning, and microUSB in one body means your iPhone, your partner’s Android, and the kid’s old tablet all charge off the same brick.
• Slim enough to use while charging. It pockets easily, and the LED display means no guessing when it’s time to refill the pack.

The catch

• “6 devices at once” is marketing math. Total output is shared wattage (15–22.5W), so loading it up with four phones slows everything to a trickle. Two to three at once is the realistic sweet spot.
• Budget-brand durability record is thinner. Charmast is a budget Shenzhen manufacturer, not a first-tier maker like Anker — long-term battery-cycle data from owners is less established.
• Built-in cables can’t be swapped. If one frays after a year of pocket abuse, the built-in port is done — though the spare USB-A ports are a fallback.
• 3A is modest for big devices. It’ll top up phones happily but charges tablets and newer large phones slower than a 45W PD brick.

Who it’s for / who should skip it

For: frequent travelers and commuters, families with a mix of USB-C and Lightning devices, and anyone who’s ever bought a power bank and then forgotten the cable. At $21 it’s also an easy stocking stuffer.

Skip it if: you need fast charging for tablets or laptops (look at Anker’s 45W-class banks instead), or you want a brand with a decade of battery-cycle track record behind it.

Price

Around $20.99, 30% off the $29.99 list price. Recent deal coverage shows it regularly landing between $19 and $26.

Where to buy

Price: ~$20.99 | Where to buy: View on Amazon

How we evaluated it

We did not hands-on test this power bank. This Rbay Finds review is researched and curated: we compared charmast’s published specs (capacity, built-in cable set, output wattage) against competing 10,000mAh banks from Anker, INIU, and VRURC, read through buyer reviews focusing on long-term cable and battery reliability, and checked its sustained #2 best-seller rank and Amazon’s Choice placement in portable power banks. Findings reflect aggregated buyer experience and published specifications, not a lab test.

3 alternatives

• Anker Nano Portable Charger 10,000mAh with retractable cable — the premium pick: 45W max output and the trusted Anker brand, but ~$50 (2.5× the price) and fewer built-in cables.
• INIU Portable Charger 10000mAh — similar budget-class pick with strong Amazon feedback and a slim metal body, but typically needs your own cable for Android or iPhone.
• VRURC Portable Charger 10000mAh with built-in cables — near-direct rival with 4 built-in cables plus a wall plug, in a similar price band, with a smaller review base.

FAQ

How many full phone charges does it hold? About 2–3.6 full charges depending on your phone model — plenty for a long travel day or a weekend away.

Can I take it on a plane? Yes. At 10,000mAh it’s well under airline limits and is TSA-compliant for carry-on.

Does it work with newer iPhones? Yes — the built-in USB-C cable covers iPhone 15/16 and current Android phones, and the Lightning cable covers older iPhones.

Final verdict

The Charmast nails the budget power-bank formula: built-in cables that end the cable hunt, a 10,000mAh capacity that covers real travel days, and a price around $21 backed by a five-figure review base. Don’t expect premium fast-charging or a decade of battery data — but for the price, it’s the bank you can toss in every bag you own. Verdict: Worth it.