Solar Charging Phone Case

Final Analysis Report

Abstract

Our project studies the development of a phone case charged by solar energy. As long as the customers are in an area with direct sunlight/light, the case will automatically charge their phones. This portable product will help customers prolong their battery life while being outdoors and having no outlet. This product will directly compete with products like a portable charger or a built-in battery phone case. Even though the battery it brings might not be as strong as the competitors, its size, weight and the convenience it brings will make up for it. Our study will focus on how much battery this solar case charges, how budget-friendly it is, and how its design can be portable for our user base.

Introduction

In recent years, the development of technology brings about many new features and utilities for mobile devices, especially phones. However, these new developments come with a disadvantage–they use up phone batteries fairly quickly. Nowadays, it is rare for phone batteries to last for a day, as more and more features are added and people can use phones for pretty much everything. This calls for a demand for portable chargers, since we are not always indoors to get a power outlet to charge our phones. We aim to look into the viability of a product that satisfies requirements of a normal portable charger but is more compact so it is more convenient to carry around, with an advantage of using solar energy so electricity would not be necessary.

Survey Design

For our survey, we included two eligibility requirements: participants had to be over 18 years old and spend a lot of time outdoors. For the first requirement, we set an age limit to make sure that participants are able to provide consent when needed. Secondly, since our study is about a wireless solar charging case, we aim to focus on individuals who are frequently outside, engaged in outdoor activities, and get exposed to a lot of sunlight. By setting this eligibility requirement, we want to understand the potential demand for our product among people who are likely to benefit from its functionality.

We collected information about our respondents’ age, location, gender and household income. By collecting information on these data, we hope to gain insights into the preferences, behaviors, geographical traits, and financial capacity of our target audience. This information will later on help us with developing a well-rounded product, marketing, and decision-making processes.

We provided the respondents with a product sample and diagram detailing how our product would look like, what its weight, price, power output, capacity, and technology type would be, along with their respective units. Using this image of the solar case design, we hope respondents could get a contextual and visual understanding of the product and utilize it in their decision-making process while taking the survey.

Product Sample

In this research survey, the attributes and levels chosen for the conjoint choice questions are:

1. Type: The attribute “Type” represents different options for our solar charging case and other portable phone chargers on the market. The levels chosen for this attribute are “Battery Pack” and “Solar Case.” These levels reflect types of products with varying features and functionalities.

2. Weight: The attribute “Weight” represents the weight of the chargers. The levels chosen for this attribute vary from 70g to 182g. These levels will help respondents take into consideration how portable and lightweight they want their chargers to be.

3. Price: The attribute “Price” represents the cost of the chargers. The levels chosen for this attribute reflect a range of price points that we think are realistic and meaningful to the target market. These prices vary from $30 - $50, which is a reasonable range for this product based on our market research.

4. Power Output: The attribute “Power Output” represents the amount of power that the different chargers can have. The levels for this attribute are 10% or 80%. The battery output is calculated in percentage charged in 30 minutes. Using these output points, the respondents can grasp how fast each option charges and find out the tradeoff they’re willing to make for each option.

5. Charge Cycles Per Day: The attribute “Charge Cycles Per Day” represents the number of times each charger can charge a phone in a day. The levels for this attribute are 1 or 3 charges. Using this measure allows us to measure the capacity of the different technologies.

For our conjoint question of the survey, each has 8 different options presented with 8 different combinations of attribute levels from the range above.

Data Analysis

Sample Description

Our sample after cleaning consists of 181 data points, spread across the US with the following descriptive statistics:

Data Cleaning

To clean the pilot survey data, we created a variable for how long each respondent spent on that part of the survey and dropped the rows where the session ID was NA in each dataframe. We joined all three data files into one dataframe using left_join on the variable session. Once the new dataframe was created, we no longer needed session, so we dropped it. We had a total of 201 data points at this point, but we had some noise from people who clicked through randomly without enough consideration for the choices. To fix this, we filtered out the respondents that completed the entire survey in less than about 2.5 minutes. We also dropped any respondents who didn’t answer all of the conjoint questions since this is a critical part of our survey. After these cleaning steps, we had a total of 181 data points.  

Once we narrowed our dataframe to what could be useful, we created the choicedata dataframe by pivoting our data longer by taking the cbc columns and turning their values into the new choice column, and the names of these options were moved to the qID variable. That variable was then converted into a numeric value using parse_number.

Modeling

Simple Logit Model

Below is the logit model we initially estimated to measure utility.

\[u_j = \beta_1 x_j^{\mathrm{price}} + \beta_2 x_j^{\mathrm{weight}} + \beta_3 \delta_j^{\mathrm{poweroutput}} + \beta_4 x_j^{\mathrm{chargecycles}} + \beta_5 x_j^{\mathrm{solarcase}} + \varepsilon_j\]

As expected, customers had a lower utility for higher prices and larger weights of the chargers and had a higher utility for larger power output, number of possible charges a day, and the solar case over the battery pack.

Mixed Logit Model

We also estimated a mixed logit model with the same baseline equation as above, but we assumed the weight, power output, and charge_cycles_per_day were normally distributed. Based on our simple logit results, we chose a normal distribution for weight because the coefficient was close to 0 and not significant, so we could not assume preferences were strictly positive. We had a similar rationale for choosing a normal distribution for power output, although this coefficient was significant. Below are the results of that model. In general, the coefficients indicate the same trends as the simple model, but they have slightly different magnitudes.

Sub Group Logit Model

The last model we estimated accounted for two subgroups: men and women. Below are the results of this estimated model. Although price was statistically significant at the 0.001 level in the first two models, it was only significant at the 0.05 level in this model, but it agrees with the negative preference for price.

Results

Willingness to Pay

The willingness to pay graphs below illustrate how customers value each of the features. People are less willing to pay for a heavier charger. For each gram that the weight increases, customers expect to see a $0.09 decrease in price or they will be unwilling to purchase it. Unsurprisingly, people are willing to pay more for a charger that charges their phone faster. People are also willing to pay more for a charger that can charge their phone more times per day. They are willing to pay $6.16 more for a charger that can charge their phone 3 times per day versus 1 time a day. People are willing to pay a lot more for a solar case than a battery pack. They are willing to pay $43.00 more to have a solar case rather than a battery pack. This could be due to the novelty of the product, it being eco-friendly, or personal preferences.  

The solar charger is estimated to have approximately 55% of the market share and is expected to lose about 10% of the market share for every $25 increase in price.

Market Shares Simulation

For our simulation, we present one competitor of our product, the portable battery pack, and study both of their probable market shares.

A market share simulation was conducted to determine the sensitivity of consumer preference for our solar charging phone case in comparison to a competing product, a portable battery pack. The simulation was designed to assess how changes in product attributes—such as price, power output, weight, and charge cycles per day—affect potential market shares for both products.

The above tornado plot represents the sensitivity of the market share to these attributes. Each bar on the graph corresponds to a different attribute and shows the potential fluctuation in market share caused by changes in that attribute. The following observations can be made from the graph:

Price: The length of the price bar indicates that price is the attribute with the most substantial impact on market share. A lower price point is strongly favorable, with consumers showing a high sensitivity to price changes. As illustrated, a decrease in price leads to a significant increase in market share for the solar case, while an increase in price tends to favor the market share of the battery pack.

Power Output: The power output, measured as the percentage of charge delivered in 30 minutes, also shows a notable influence on market share. Consumers prefer products that can charge their phones more quickly, as indicated by the sizable market share swing towards the charger with higher power output.

Weight: The weight of the product is another critical factor. The market share is inversely related to the weight, with a lighter product being more desirable. The graph shows a moderate variation in market share with changes in weight, suggesting that while important, it is less of a factor than price or power output.

Charge Cycles Per Day: Lastly, the number of charge cycles per day that a product can support has the smallest impact on market share among the attributes we tested. However, the ability to charge multiple times a day is still a value-adding feature, as evidenced by the slight preference for higher charge cycles.

The simulation indicates that price is the primary driver of market share, followed by power output and weight. The solar charging case shows a competitive edge over the battery pack in scenarios where it is priced competitively, offers superior power output, and maintains a lower weight profile. Charge cycles per day, while less impactful, still contributes to overall product appeal. To maximize market infiltration, the solar charging case should be optimized for cost-effectiveness, rapid charging capability, and lightweight design. This strategic focus is expected to capture a larger market share from the battery pack competitor and establish the solar case as a leading product in the portable charger market.

Sensitivity Analysis

Our research has revealed a strong consumer inclination towards a lightweight and efficient solar charging phone case. This preference is rooted in the increasing need for mobile energy solutions that are both eco-friendly and convenient for on-the-go lifestyles. The solar charging case, as a product, capitalizes on these needs by offering a sustainable energy source without the bulkiness of traditional portable chargers.

We also conducted a sensitivity analysis to figure out how the changes in our price affects the potential market in this plot.

The baseline price for our product is $30 per solar charger. Evidently, we see that the model is sensitive to price as the observed market share decreases from about 63% to 55% with a $20 increase in price, while the predicted market share could fall to only about 33% with a price of $100. Since this product is at the early stages and the real cost of production has not yet been determined, it is possible that these solar chargers would be sold at a higher price point to ensure at least a breakeven point.

As for revenue, our analysis shows that as the price increases, revenue also increases as market shares don’t drop too drastically within this range. As above, the revenue only starts stabilizing $75 and up. Currently, the best price point for this product is likely around $30-40.

Limitations

Our study has 181 respondents, which is around 100 respondents fewer than what was needed for the results to be significant based on our power analysis. Therefore, the findings may not accurately reflect the preferences and behaviors of the target market.

We only took into consideration one competitor for our market share simulation which is not a big enough representation of the current battery charger market.

Our conjoint analysis conducted in the study only focused on attributes such as weight, price, power output, and charge cycles per day. Other important factors that could influence consumer preferences, such as durability, compatibility with different phone models, and ease of use, were not included in the analysis but will be considered for future steps.

Recommendations for Product Development

Weight Optimization: The data suggests that the lighter the charger, the more appealing it is to consumers. Efforts should be focused on minimizing the weight of the solar charging case without compromising its durability and efficiency. Materials such as lightweight polymers or composite materials could be explored.

Efficiency Enhancement: The solar charging technology should be optimized for faster charging capabilities. This involves investing in high-efficiency solar cells and ensuring that the power conversion process is as effective as possible.

Design and Aesthetics: While functionality is key, the design should not be overlooked. A sleek, modern design that appeals to a wide range of consumers should be pursued. This includes considering different sizes to accommodate various phone models and possibly offering a range of color options.

Price Point Strategy: While there is a willingness to pay more for solar technology, pricing should be strategically set to balance affordability and perceived value. Competitive pricing, possibly through tiered options based on features, can cater to different segments of the market.

Environmental Impact and Branding: Highlighting the eco-friendliness of the product can be a significant selling point. Marketing strategies should emphasize the sustainability aspect, aligning the brand with environmental consciousness

Final Thoughts and Conclusions

The solar charging phone case has the potential to be a good competitor in the portable charger market, assuming production is feasible. The feedback, both quantitative and qualitative, from the survey indicated that people have a preference for the solar charger. Some of the comments in the survey conveyed the sentiment that eco-conscientious people would be willing to pay a much higher price for this product which we were not able to measure these sentiments in our quantitative analysis. We have tentatively priced the solar charger between $30-$50 which is comparable to the market, but this price is subject to change based on how much it realistically costs to produce it.

The main feature of concern at this stage is the power output of this product and its feasibility. The comparable portable chargers in the market have a much higher power output that solar power simply cannot produce at this time. However, it might be that people would be willing to forgo that speed of charge in order to help preserve the environment. Our analysis has shown that people do prefer the solar charger over the portable battery pack which is encouraging.

Appendix