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Logitech Wireless Solar Keyboard K750

November 14th, 2010
Logitech tries its hand at infinite battery life.

Logitech's K750 attempts to solve one the most basic frustrations with wireless keyboards: having to buy and charge batteries. The unit has two solar strips built in, which Logitech claims are sensitive enough to keep the keyboard running off of artificial light, and not just the sun. We'll see whether this claim holds up, and whether the K750 works as a keyboard in general. Setup

Although it does operate with Macs, the K750 is only officially compatible with Windows systems, and was tested in Windows 7. Logitech supplies very little in the box: there's the keyboard, a cleaning cloth and a two-part RF receiver used to connect to a computer. Technically, only one piece of the receiver is actually needed -- because it's designed to sit flush with a notebook's USB port however, an adapter makes life easier for desktop users.

Beyond some simple diagrams on the packaging, the only manual for the keyboard is at Logitech's website, and this is just as well. Installing and configuring the K750 can't be much easier. A watch-style battery comes pre-inserted, and after plugging in the receiver and flipping the keyboard's "on" switch, a Logitech configuration program kicks in automatically for Windows users.

The process puts a piece of software called the Solar App on your computer, which is triggered by a special hardware button and displays light levels in the form of a lux meter, and battery level as a percentage. The meter has to stay above a certain threshhold in order to avoid draining the battery; two lights on the keyboard, alternately, can be used to determine a simple "good" or "bad" lighting situation.

Look, layout and basic use

The design of the K750 is strongly reminiscent of Apple's stock wired keyboard, complete with chiclet-style keys and an extremely thin body, less than a third of an inch thick. The K750 is almost entirely made of plastic though, and if there are any meaningful quality complaints to be aimed at the product, they're right here. Materials feel slightly more fragile than they should, particularly in the support stands, which could break if a person were to slam their fist down hard. The surface of the keyboard is also intensely glossy; while aiding sex appeal, this also means that that cleaning cloth is going to have to sit close at hand. In less than a day of testing, some early signs of specks and lint began to appear.

The keys are extremely quiet on the other hand, something bound to be welcome in a lot of offices. One thing neither here nor there is Logitech's decision to make K750 a compact non-ergonomic keyboard, with commands like music controls demanding that users hold down a toggle while pressing one of the function keys. Some people may prefer the comfort and convenience of a full-sized ergonomic keyboard, but an important tradeoff is portability and a smaller footprint.

Power tests

As mentioned at the beginning though, the real attraction of the K750 is where its power comes from. So long as a decent amount of light is hitting the solar strips, the battery should always have a charge, and may never need replacing. In several days of testing, in fact, the battery never dipped below 100 percent, even when the keyboard was on in the darkness overnight.

This is probably linked to the strips only registering poor levels of light when a room is unreasonably dark. Absent times without any light whatsoever, the only point during testing when the keyboard was theoretically losing energy was a Saturday evening at sunset, when it was also obscured by shade. Light dipped down to just 23 lux, but quickly jumped back to acceptable levels when an overhead incandescent bulb was turned on.

In bright midday light, the K750 hit a peak of 312 lux, well into the Solar App's high range. Normal sunset conditions gradually cut levels to around 45 lux, which is barely acceptable. At night, with an overhead lamp on, levels sit between 49 and 52 lux. Nighttime may result in significantly greater drain with less direct sources of light, such as a lamp aimed at a wall or ceiling.


For obvious reasons, perhaps, it's difficult to do a definitive review of the K750. In theory, it could take years before drain might even start to take a toll. In the short term though, the keyboard appears to deliver on the promise of a wireless model that doesn't have to have its batteries removed and charged every couple of weeks. The ultimate question -- mostly a matter of preference -- is whether it's worth $80 for the convenience, especially when the K750 lacks the luxuries of full-sized ergonomic rivals. The answer may well be yes.
- Indefinite battery life.

- Quick, automatic setup.

- Very quiet keys.

- Attractive design.

- Relatively delicate construction.

- Missing keys, comfort of full-sized ergonomic keyboards.

- More expensive than some competing compacts.