Alternative power sources : final project report

Classroom radios need fairly large speakers and have correspondingly high power requirements. The cost of this power is also high because most developing country schools, especially those in the poorest rural regions, lack public utilities and must use batteries, which may cost as much per year as the radio. The Alternative Power Study was undertaken by the Radio Learning project to investigate alternatives to battery power, especially solar power. Although solar power for radios has been discussed as an alternative for years, and even tried in several sites, it is only recently that the cost has decreased enough to make it a genuinely feasible alternative. The project experimented with a number of configurations of radios and solar panels. Two panels promised to work well with the GE SuperRadio, a radio that is being used as a classroom radio in several countries, including the Dominican Republic and Honduras. Since an apparatus that works well in the laboratory may not work as well in actual practice, a field test was planned. Eight typical rural schools in three different climate zones in Honduras were selected as test sites. A solar panel was installed on the roof of each school, with a lead going down to the radio. The radio could be unplugged from the solar panel when desired. Thus, the radios could be moved about, but the solar panels were fixed. Both configurations that worked well in the laboratory were used in the field tests. The sites were visited twice, first at initial installation, then several months later, to see how well the equipment was working. The apparatus itself was inspected, and teachers were asked to express their experiences and feelings about the use of solar power. Both solar panels worked well, but it was clear that the large panel was more acceptable to teachers. Those who had the large panels reported a higher degree of satisfaction with battery life (before recharging) and with sound quality. The situation in Honduras is unique in one way: the teachers themselves own the radios. There are two consequences of this: first, the radios are unplugged from the solar panels at the end of the school day, which is usually very early in the afternoon; consequently, the batteries were not charging during some of the peak sun hours (from about 10 AM to 3 PM). Second, the radios were used by the teachers at home, on battery power only, for four or five hours a day. In this circumstance, the large solar panel was found to be more acceptable. In places where more of the peak sun hours would be used, or where the radios are not run for as long a time simply on battery power, the small panels would be a successful, and cheaper, solution. One disadvantage of the large panel is that, with strong sunshine, it can deliver enough power to damage the radio. This needs further investigation, but it is possible that a charger controller might be needed, which would add to the cost of the package. (Author abstract, modified)