An F9 case is two things at once: a charger for the buds and, on most versions, a small power bank for your phone. Charge it right and one pair covers a week of gym sessions.
Fresh as of September 2026Plug the case into a USB wall adapter with the cable from the box; the LED digits climb as it fills, usually over one to two hours. Drop the buds onto their cradles and they charge on contact. Buds play roughly 3 to 6 hours per charge, and the case refills them many times over.
Charging starts with the case, not the buds. Plug it into a USB wall adapter or a laptop port and the LED readout starts counting up.
Most F9 cases fill in one to two hours. BMHOLU quotes about 1 hour for its F9-5 case, NC and Avalanche Market about 1.5 hours, BSWLMDD and DB LLC about 2 hours.
A 5V adapter rated 1 to 2 amps is plenty. Fast chargers work too, because they fall back to 5V for a device that asks for nothing more.
Then seat the buds. Each one drops onto a magnetic cradle and charges on contact. On the Harigal F9-5C Twin Display, charging cuts off at full, so an overnight top-up is safe.
Buds refill faster than the case. BMHOLU puts a full bud charge at about 40 minutes and Voltstech at about an hour, so a lunch break covers an evening session.
| Pair | Case battery | Readout | Charges a phone |
|---|---|---|---|
| BSWLMDD F9 | 1,200mAh | Case percentage | Yes, as emergency power |
| MDNS BTH-F9-5 | 2,000mAh | LED battery levels | Power-bank case |
| Volt Plus Tech F9 power bank | 2,000mAh | Case and buds | Yes |
| NC F9 | 2,200mAh | Case and buds | Yes, and stands the phone up |
| Voltstech F9-5 | 1,500mAh | Case and buds | Yes, over its USB port |
| Huiye F9-5 | 3,600mAh | Percentage | Yes, emergency charging |
| BMHOLU F9-5 | 500mAh | Power display | Not stated |
Capacities and features as each maker states them. Real phone top-ups come out lower than the cell figure because of conversion losses.
The glowing digits are the F9's signature. On some cases they show only the case's own charge; the better ones add each bud.
Flashing digits usually mean charging in progress; steady digits mean the case is idle. A reading that drops from 30 to 10 under a phone load is normal, since cell voltage sags while the case works hard.
The display draws a little power itself, so most cases blank it after a few seconds. Open the lid or seat a bud to wake it.
A readout that shows each bud earns its keep when one side fades early. Spot it on the lid of the DCBCODGAL CF9 and clean that cradle before the side dies mid-run.
|
BSWLMDD F9 Earbuds |
MDNS BTH-F9-5 Sport Earbuds |
Volt Plus Tech F9 with 2,000mAh Power Bank |
Huiye F9-5 with 3,600mAh Case |
NC F9 with 2,200mAh Case | |
| Type | F9 | F9-5 | F9 | F9-5 | F9 |
| Case | 1,200mAh power bank | 2,000mAh power bank | 2,000mAh power bank | 3,600mAh power bank | 2,200mAh power bank |
| Battery readout | Yes | Yes | Yes | Yes | Yes |
| Water rating | — | IPX7 | IPX7 | — | IP7 |
| Bluetooth | Bluetooth 5.3 | Bluetooth 5.0 | Bluetooth 5.3 | Bluetooth 5.0 | Bluetooth 5.0 |
| Playtime (with case) | 48h with the case | — | — | — | 126h with the case |
| Grab this pair | Grab this pair | Grab this pair | Grab this pair | Grab this pair |
F9 earbuds battery life splits into two numbers: how long the buds play per charge and how many refills the case holds. Makers quote both, and they vary a lot across the range.
| Pair | Buds per charge | With the case | Case battery |
|---|---|---|---|
| MDNS BTH-F9-5 | Up to 5 h | 120 h standby | 2,000mAh |
| BMHOLU F9-5 | Up to 5 h music, 4 h talk | Up to 30 h music | 500mAh |
| NC F9 | 5 to 6 h | About 126 h extra | 2,200mAh |
| Voltstech F9-5 | Up to 6 h talk | Not stated | 1,500mAh |
| Volt Plus Tech F9 Pro Touch | 5+ h | About 25 h | 2,000mAh |
| DB LLC F9-5C | 3 to 4 h | 130 h standby | Not stated |
Standby and total figures swing with volume, calls and temperature, so treat them as ceilings. A loud gym playlist and cold morning runs both cut real listening time.
Long weekend away? The biggest case in the range belongs to the Huiye F9-5: 3,600mAh with wireless charging. Every version's case capacity is lined up in the F9-5 vs F9-5C, Pro and Mini comparison.
NC's F9 pairs a 2,200mAh USB-C case with buds rated for 5 to 6 hours each. The case refills them about 20 times and tops up a phone in a pinch.
Grab this pairMost power-bank F9 cases hide a USB-A socket on the side. That socket is an output: plug your phone's cable into it and the case turns into a small power bank.
Expect a top-up, not a full refill. A 2,000mAh cell at 3.7 volts holds about 7.4 watt-hours, and after conversion to 5V roughly 60 to 70 percent reaches the phone. That is about a quarter to a third of a typical 4,000 to 5,000mAh phone battery.
F9 earbuds power-bank cases across the range:
Slim pockets beat power banks on some days. The F9 Mini from Volt Plus Tech drops the phone-charging feature for a thin case that disappears into running shorts.
A case that will not charge usually comes down to a cable, a port or a deeply drained cell. Work through the causes in order and most cases come back.
Case charges but the buds do not? Clean the pins in each cradle and the contacts on each bud with a little isopropyl alcohol, then reseat. The F9 reset steps help when a bud charges yet stays silent.
The case takes about 1 to 2 hours from flat, depending on the model. Buds refill in roughly 40 minutes to an hour on their cradles.
Buds play about 3 to 6 hours on a single charge, set by the model and how loud you play. The case adds anything from about 20 to over 100 hours of refills.
Swap the cable first, ideally for a USB-A to USB-C lead, and check you are using the input port rather than the USB-A output. A deeply drained case may need 30 minutes before the digits light up.
Yes, on power-bank versions with a USB-A output. Expect a partial top-up: a 2,000mAh case gives a typical phone roughly a quarter to a third of a charge.
It is the case's remaining charge in percent. Cases with three readouts also show the left and right bud levels.
