Why Solio Makes the Best Solar Chargers.

At Solio we are singleminded about lightweight, minimalist products that fit into your pack unnoticeably. Through our unique proprietary designs, we have put together the best combination of solar panel and smart battery and added special optimized discharging modes for both the Wireless Industry USB standard used by Android devices and the exact protocol for charging Apple “i-Devices” the iPhone, iPad, and iPod.

What Makes the Best Solar Charger?

Since Solio invented the hand-held solar charger we have a strong opinion about what it takes to make a good one. There are four parts to a great solar charging experience.

First, the device should be small and lightweight enough that you have it with you when you need it. Second, the solar charger must flawlessly discharge to all sorts of USB powered devices with exactly the right charging protocols. Third, there should be a smart and high temperature rated battery designed for solar use as part of the design. Lastly, the quality and efficiency of the solar photovoltaics must be designed for small devices.

Small Size. Light Weight. Perfect Ratios.

Power to size ratio is very important - we think a product is only useful if you actually have it with you when you need it. We have worked to balance the ratio of small size and highest functionality in power management. Competitors add extra “ruggedization” features which simply add weight and cause thermal build up. We are the company that first brought pocket sized solar products to market 10-years ago and we understand better than most what makes products last in the field. Our products are rugged by design not by added features. Like Saint-Exupery we feel that design “perfection [is achieved] not when there is nothing left to add, but when there is nothing left to take away”.

Exactly the Right Charging Protocols

Only Solio has built-in a special mode to ensure optimized charging for Apple® “iDevices” every time. Because iPhone®, iPad®, and iPod® products have more sensitive charge requirements than many other electronics, Solio has built is a special mode just for iDevices. All Solio models are iPhone, iPad, iPad Mini, and iPod ready- no special cables required.

Solar Smart Battery Onboard

The Solio approach is to first charge a solar smart battery from the sun, then discharge that energy to a target device like a phone or headlamp. This means that your energy receiving electronics gets uniform power every time without current drop-outs when the sun passes under a cloud or a bird flies overhead. Capturing energy onto a solar smart battery has the additional benefit of keeping your electronics mobile and allowing you to be ready to recharge them– no matter the conditions - day or night. Direct solar charging is a bad idea- even though our competitors promote it. Why would anyone would want their expensive electronics to bake in the sun? It is bad for their battery and housing materials - not designed for high heat and intense UV exposure. Abbreviated Li-poly, Li-Pol, LiPo, we use specially designed hi-temp lithium ion polymer batteries. Solio batteries are designed with extra charge-control protections for the extreme heat conditions of solar charging.


Not all Solar Panels are the Same

Solio utilizes the highest quality wafer silicon photovoltaics - tested for a minimum 17.5% efficiency- the highest reliably commercially available. Beware of amorphous or so-called flexible, rolling or thin-film solar cells that claim to work better in low light conditions but never ever work beyond 8% conversion in full sun conditions.


More Background about Charging Protocols

Charging protocols are important to a good user experience. Apple “i-Device” products are especially fickle with solar charging and battery packs. At Solio we have a special output mode built into our products that makes them backwards compatible with all generations of Apple “i-Devices” while we have a second mode built for the wireless industry (CTIA) standard. Of course the fact that we use a battery as a “buffer” between solar energy input and discharge means that your electronics will always receive a uniform power supply— just the way they like it.

Even more background: When USB was first adopted by the market in 1998, the original specification for power output was only 150mA. As time went on, additional specifications for outputs of 500mA, 900mA and eventually 2A were established to supply power more quickly. Because the same physical connector (USB) is used for all these multiple generations of standards – there also needed to be a way to indicate to the connected device that it can safely draw higher current (or not) — and that was accomplished through use of the data lines of the USB cable. If a device was set to allow the draw of too much current the results could be as simple as the device shutting down, or as disastrous as the device or charger overheating and self destructing.

The real problems came when batteries got bigger and the need for higher output rates evolved quicker than the standards, so manufacturers developed proprietary techniques to communicate the charging requirements to the discharging device. Of course these manufacturer solutions are competing and incompatible with each other and with the Wireless Industry (CTIA) power and charging specifications. So today there is a mess of incompatible gear in the marketplace and consumers are confused. Sometimes the charging experience seems smooth and other times there is a problem or and error message. Most chargers either support one proprietary standard or one CTAI standard but nothing else. Many manufacturers side-step this compatibility issue completely by calling their device “Universal” when all that really means is it will discharge at the lowest rate the target device perceives as safe. This means a charging device that is capable of fully charging connected device’s battery in an hour could actually take 2 hours to charge if the target device doesn’t recognize that it is connected to a compatible high-power charger.

At Solio we are concerned about a good user experience -solar charging provides enough variability— users should not have to worry about the physical connection USB connection being made but the target device not charging correctly. We’ve built in the two main standards for 1AMP output and allow users to switch between them for an optimized charge rate. View our support section for more information about changing discharge modes.

More Background on Solio Solar Smart Batteries

Solio battery designs have a very low self discharge rate and excellent shelf life in storage if stored ideally at 40 to 85F . During storage remaining battery capacity should be 40%~50% of full charge capacity. If competitors use a battery at all, other solar devices often use NimH or NiCd battery chemistry which do poorly in storage and have a high self-discharge rate. Some competitors use Lithium-ion cells which do not have any special charge control safety design for solar charging and will easily exceed safe operating temperatures and shut down or be ruined by the extreme heat. In terms of life span, the Solio battery is designed to retain up to 80% of its original capacity at 500 full charge and discharge cycles, the point at which the charge capacity of the battery declines to 80% of the as-built capacity. Eventually batteries may have permanent capacity loss; which as the name implies, refers to permanent loss that is not recoverable by charging. For this reason, we have built Solio products for easy battery replacement by end-users. We have partnered with iFixit on guides for common Solio repairs- see our support section for more information.




More Background on Photovoltaic Solar Panels

Some competitors use thin-film cells which uses amorphous protocrystalline, nanocrystalline or black silicon. Thin-film silicon is opposed to the wafer silicon we use (monocrystalline or polycrystalline). The solar cells made from competitors amorphous materials tend to have lower energy conversion efficiency than our wafer silicon, but are also less expensive to produce. To its credit, Amorphous silicon has a higher bandgap than crystalline silicon, which means it absorbs the visible part of the solar spectrum more strongly than the infrared portion of the spectrum allowing it to work in lower light conditions but never work well in full sun conditions. Solutions to overcome the limitations of thin-film silicon have been developed but none or yet commercial leaving the efficiencies of thin film well below those of wafer silicon cells. The moment a better technology than wafer silicon is available we will use it!