Even if solar power running cost is very low, the related initial investment cost might be high, and, therefore, it raises a barrier for the adoption of solar power products by wide segments of the population. If lanterns are the best selling off grid solar power product, this does not mean, in most cases, that users needs are limited to the use of a lamp and the recharge of a cell phone. The most successful off grid solar power companies always offer their products together with the financial mechanisms that will make the payment affordable for all and the products accessible for the majority.

In addition to the financial constraint related to user's budget limitations, products design is also a constraint: an undersized system will not produce what users expect and an oversized system will cost unnecessarily expensive.

An off grid solar power system is designed to meet the needs of a specific user. Beyond the purpose it was designed for, the system might stop. Moreover, the photovoltaic conversion depends on the intensity of the sunshine. This means that below the expected sunshine, the system might also stop working. The most reliable systems integrate a generator to ensure battery charging under all conditions.