Soundboks 4: battery life and spare battery

Two figures, a wide gap

Forty hours on one side, six on the other: the gap is huge, and it has an explanation. The Soundboks 4 has 3 class D amplifiers of 72 W RMS. At medium volume they need little energy; at full volume they need far more. Soundboks states that the speaker can play at 126 dB for 6 hours.

There is no universal definition of “medium volume”. Take the 40-hour figure as an order of magnitude, not as a promise for your evening. The most useful thing is to remember the principle: the louder the sound, the shorter the battery lasts, and not in a proportional way.

To estimate your evening, here are orders of magnitude drawn from the announced figures, not measurements:

• a 5-hour evening at full volume uses almost the whole battery;
• a 6-hour evening at medium volume uses less than a sixth of it;
• a weekend of two evenings at medium volume stays within the 40-hour margin.

This calculation assumes a constant volume, which never happens: the background music during drinks barely uses the battery, while the moment everyone dances uses much more. Always keep some margin. Turning the volume down a notch when the mood allows it is the move that stretches the evening the most.

What else drains the battery

Volume is the main factor. The second is more discreet: the battery also works as a power bank. Its USB-C output delivers 5 V 2 A, with no fast charging. Fully charging a smartphone cuts the battery life by about a fifth, according to Soundboks.

If your phone is nearly flat in the middle of the evening, the temptation is to plug it into the speaker. Do so if you have to, but knowing that you are cutting into the music time. On a long evening, a pocket charger for the phone is more economical.

The battery: removable, LiFePO4, 99.84 Wh

The Soundboks 4 battery is called “The Battery”. It is removable, LiFePO4 technology (lithium iron phosphate), 12.8 V, 7.8 Ah, that is 99.84 Wh. It is compatible with all generations of Soundboks. You take it out of the speaker and slide another one in: that is what makes the spare battery simple to use. Since the speaker is handed over with its battery charged and checked together at departure, you start the evening with a full battery.

The Soundboks 4 has its amplifiers built in: it is an active speaker. If you are interested in the difference from a passive speaker, our article active or passive speaker: what changes covers it in detail.

When to take the spare battery

The option makes sense in three cases: a weekend with two evenings, an evening that has to last all night, a party where the volume will stay high. In these cases, a second charged battery saves you from interrupting the music. For a single evening at medium volume, the battery handed over with the speaker is more than enough. The rental lasts from 1 to 7 days, the price depends on the duration and is shown on the page, like the price of the option. To decide, ask yourself a simple question: how many hours of music, at what volume, with no possibility of recharging? If the answer is more than a few hours at high volume, take the second battery.

Recharging on site

Charging is done via USB-C. According to Soundboks, with a 65 W USB-C PD charger, the kind used by a laptop, the battery recharges in 2 hours. With 45 W, allow about 2 h 48. On a 5 V 1.5 A USB port, about 18 hours: a port of this type is therefore only suitable for an overnight charge. You need a charger of at least 10 W. You can play while the battery is charging, even at full volume, between 0 and 40 °C.

No charger is announced with the rental. If you plan to recharge, bring a laptop USB-C PD charger. You also need a power outlet: without one, consider the spare battery option, and read our article on how to set up sound for an outdoor party without a power outlet.

Returning the battery

On return, at Lyon 3, every day from 9 am to 8 pm by appointment, bring back the speaker with its battery, and the spare battery if you took it. There is no shipping. The speaker is checked together with you; if you took the Shure SM58 microphone as an option (€5 per microphone per rental, two at most, XLR cable supplied and microphone stand free of charge), bring it back with its cable and stand. You can compare it with the RCF ART 912-A pair if you have a power outlet, as it runs on mains power.

See speaker rental in Lyon