Does School Server Need a Lead Acid Battery Interface?

I was describing my efforts to use an Arduino microcomputer to monitor lead acid batteries to a battery sales engineer in the Philippines. His reaction was that it would be a great opportunity to include a de-sulfating circuit.

I knew nothing about de-sulfating, but the issue of lack of power in the developing world keeps resurfacing in my reflections. So I’ve been doing research on the internet about batteries.

It turns out that the people in the developed world, who are trying to live off the grid, have been learning a lot about how to get better service from lead acid batteries. (This reference was the first I found about repairing lead acid batteries). The basic idea is that wet lead acid batteries don’t last very long (only 1-3 years), because the lead plates become coated with a layer of inactive lead-sulfate crystals. By pulsing a battery with high current for a very short time (a few thousandths of a second), this inactive layer can be removed. (Later I discovered a whole forum about the desulfating process).

I think that many schools in the developing world will need lead acid batteries and solar panels or battery chargers, if the school server is going to be useful as a local content server, and a connection to the global internet. And if there is power available for the school server, teachers are going to want to charge their cell phones while they are at school. Who knows how many other demands may be made for power? So there needs to be a way to monitor the charge in the system, so that these additional needs can be serviced without degrading the main purpose of providing the school server functions.

My vision is that both of these needs, the de-sulfating, and the battery system monitoring, can be served by the same gadget. It would connect to the battery and also the school server. It would prolong battery life, and also provide valuable insight into the health of the power system which is essential for proper functioning of the school server in areas of the world where power is not reliable.

Ideally, this gadget, would have a lcd (liquid crystal display) which directly announced the percentage of charge, and the total charge available when the battery is down to its half power point.  This “half power charge” capacity will decline over time, but it will give some warning and visibility into the declining health of the battery, and the need for attention, or replacement.


About George Hunt

Retired electrical engineer and programmer, enthusiastic about OLPC as a vehicle for gathering together volunteerism, mine and so many others', for helping education in developing countries.
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