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Falsehood alert for the sun helmet (but it's still a good idea!)

19.12.2019

Translation: machine translated

In fact, I don't like picking on things. But when I see this solar helmet, where JBL's marketing department is making one stupid mistake after another, I have no choice.

"Self Charging. Endless Playtime."

The JBL Reflect Eternal is an interesting product, as the wireless over-ears headphones feature a solar cell in the headband that allows continuous operation - hence the name Eternal - without a power outlet. The Bluetooth headset is not yet available for purchase. It is being developed via crowdfunding on Indiegogo. According to the project page, the whole thing is at the prototype stage.

What you still need to know is that JBL has been owned by Harman since 1969. And, since 2016, Harman has been part of Samsung. Basically, JBL doesn't really need to rely on crowdfunding. JBL uses Indiegogo as a marketing tool and relies on its contributors to become ambassadors for the product.

Bad math on JBL's part

If the description is to be believed, the solar cell would work even with artificial light. This should be made possible by "Powerfoyle" technology from Swedish company Exeger. JBL also claims that with just 1.5 hours of sunlight, you should gain 68 hours of battery life. The small print indicates that 50,000 lux was used for the application examples. These are bright conditions on a slightly cloudy summer's day. With artificial light in the office - around 500 lux - there shouldn't be much charging power left.

JBL's sample calculations leave me with an uneasy feeling: the 700 mAh battery capacity should be enough for 24 hours of operation. So why are they telling me that an hour and a half of sunlight is enough for 68 hours? It's not as if I can overcharge the battery to keep myself supplied.

Nonsense.

A miraculous solar cell with unheard of efficiency

Next, I check the performance data for Egexer's "Powerfoyle" solar cell using some simple maths.

Solar radiation at our latitudes is around 1000 watts per square metre.
Good cells offer 20% efficiency.
Theoretically recoverable energy per square metre is therefore 200 W.
The energy actually collected per m² is around 100 W, as the sun does not always strike the cell perfectly at right angles and conversion losses occur.
The solar panel on the JBL headphones is, being generous, 20 cm long and 3 cm wide, or 0.006 m².
Thus, the panel delivers 0.6W if it has commercial efficiency values.
The battery offers a capacity of 700 mAh at 3.7 V, which allows 2.59 Wh to be stored.
As 700 mAh equates to 24 hours of operation and an hour and a half in the sun provides, according to JBL, 68 hours of headphone autonomy, the solar band delivers 1983 mAh in ninety minutes, or 1322 mAh per hour. That's 4.89 Wh from 3.7 volts of energy.

As a reminder: the energy (1000 watts per m²) emitted by the Sun and reaching the Earth is 6 W per sunny day for a surface of 0.20 m × 0.03 m amounts to 6 W per sunny day.

It is therefore impossible to recharge the battery almost three times in just an hour and a half. Unless Exeger have developed a solar cell that has an astonishing 76.5% efficiency level. In that case, I'm already congratulating them on the Nobel Prize.

Once again, it's all bullshit.

Here's JBL's reaction:

And mine:

Still an interesting product

Even if the performance data advertised are purely fantasy values, the concept is interesting. Even if the panel only extends the listening pleasure a little, the idea is a good one.

The other data for the JBL Reflect Eternal:

the headphones will be available in green and red;
it does not offer noise reduction, but an "Ambient Aware & Talk Through" function, which corresponds to the "Transparency Mode" of the Airpods Pro;
quick charge function offering 2 hours of use for 15 minutes of charging. The battery is fully charged after two hours;
the Reflect Eternal supports Bluetooth 5.0. JBL does not yet specify the codecs supported;
IPX4 protection rating ("Splash protection from all sides") ;
the headset currently costs $99 on Indiegogo and can still be purchased in the cheapest package.

I dare say that if the Reflect Eternal works properly, it will end up in our online shop. If you want to be one of the first to own the JBL Reflect Eternal, you can back the project on Indiegogo until 14 January 2020. The product is due to ship in October 2020. Personally, following the fancy marketing, I'd wait for solid reviews to be published before buying it.

51 people like this article

Aurel Stevens

Chief Editor

aurel.stevens@digitecgalaxus.ch

I'm the master tamer at the flea circus that is the editorial team, a nine-to-five writer and 24/7 dad. Technology, computers and hi-fi make me tick. On top of that, I’m a rain-or-shine cyclist and generally in a good mood.

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