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Power Options for Charging Smartphones in the Field Cody Winn East Africa Coffee Initiative July 2011 SUMMARY TNS East Africa CI is evaluating the feasibility of deploying smartphones with applications for use in the field. The phones and applications can have significant benefits, and 98% of Rwanda is covered by mobile internet, but the biggest concern is the lack of power for recharging the phones. Very few wetmills are connected to the electricity grid. Wetmill employees generally walk some distance to the nearest mobile charging station in a village, drop their phone, and pick it up at the end of the day. This is not a feasible option if they are expected to use the smartphone throughout the day. This presentation outlines a number options for charging smartphones in the field. There is no clear product that will work successfully – field studies should be done before moving forward with this project. Generators Details Some wetmills were provided with generators for powering equipment Concerns Generators frequently broke down and had to be returned, and are not reliable Generator charge fluctuates, and thus is not recommended for electronics because it can fry the battery More expensive generators with an AVR (automatic voltage regulator) or with an additional battery for charge storage would be required Recommendation Not a viable option, too unreliable for electronics Solar panel + Powertank Details Create a kit from a solar panel plus a power storage battery (by itself, a small solar panel generates 125-500 mA of power, which is not enough to switch a smartphone into charging mode) Sample battery: Swisscharger Powertank L Includes multiple outputs and adaptors to charge light, radio, phone, etc Cost $40 (Powertank) + solar panel cost Concerns Would need to assemble a kit from different parts – may be support requirements Any solar solution will require strong sunlight, so no charging can be done at night or during rains, a significant concern as the harvest is during the rainy season. Field studies and online reviews show disappointing results using solar to charge smartphones. The power generated from solar is often not enough to meet the daily battery consumption of a smartphone Recommendation Probably better to use a product that combines both (see next slides). Field testing should be done with any candidate solar products to evaluate performance. d.light s250 Details Already used at wetmills for night lights Solar panel + battery embedded within a light Includes phone charger connection Cost $60 Concerns Not strong enough to keep a smartphone charged if needed for regular use – solar power stored per day is less than an Android phone needs to recharge Concerns about life of battery Other considerations d.light is continuously doing R&D and will come out with stronger, cheaper products over time Recommendation Not a viable option now, but company’s products should be monitored for 2012 season Fenix ReadySet Details Can take charge input from solar panel, stationary bicycle, or grid Low-maintenance, optimizes battery efficiency through software, will last 3 years Can charge multiple phones, lights, radio, etc Grameen Uganda has deployed these into the field for 4 months and is happy with results so far Cost $150 retail, possibly cheaper for large purchase or NGO use Concerns Very expensive - it is not a charge generator in itself, solar panel is also required Other considerations A bicycle can generate significantly more power than solar (100x per same unit cost). Wetmills have expressed opposition to biking for power but it could be an efficient option. Recommendation Discuss minimum cost of product + solar panel with Fenix. Re-think whether wetmills could hire day laborers to pedal a bike and charge a battery. Solio Classic Hybrid, PowerCurve Solio Classic Details Similar products: solar panel + internal Li-ion battery Claim to fully charge in one day of sunlight but online reviews say this doesn’t often happen Various outputs for charging phone, light, radio, etc but only can charge one device at a time Cost $40-$90 Concerns Online reviews of use of these products to charge smartphones are not positive– eg: “When fully charged from the wall the battery pack would only take my phone from 10% up to about 40%. Since it takes so long to charge in the sun, this rate of charge is unsustainable” Will only charge a smartphone up to about 75% full but some reviews say 60% is more common Recommendation Unlikely to be sufficient, but can try to get demo products to field test the performance PowerCurve Great Lakes Energy – reseller of 2 solar products Details Solar re-seller based in Kigali, recommend 2 products: Greenlight Planet Sun King Pro Trony Sundial Both are similar to d.light – solar panel + battery embedded within a light - but newer and better Battery should last multiple years Cost $70 each Concerns Initial field test of a Trony Sundial charging a Huawei Ideos phone was not positive After charging the battery for 1.5 days in fairly strong sunlight, the battery only intermittently charged the phone – the phone wouldn’t recognize the charger 100% of the time. Even while successfully charging, the phone battery only increased 7% in one hour. As with all solar products, performance in rainy season is a significant concern Other considerations Could replace the d.light for nightlight use as well Great Lakes also sells a larger but similar Philips product for $140 Recommendation Continue talking to Great Lakes and do more field testing on their products