Transcript Here`s - As The Water

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