Julian on December 8th, 2012

In the late 19th century, Westinghouse and Edison slugged it out over whether electricity should be distributed as alternating current (AC) or direct current (DC). Transmission of electricity over large distances requires very high voltages to minimise losses and AC transformers were far simpler than DC motor-generator sets at that time. So AC won and [...]

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Julian on November 20th, 2012

Project Banana is nearing completion. The idea is to make up a kit of connectors to simplify connecting the PWM5 between a solar panel and a battery. On the battery side, there’s a pair of modified crocodile clips which have banana sockets attached. The positive croc clip has two red banana sockets and the negative [...]

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Julian on November 3rd, 2010

Bootstrapping is the process of picking one’s business up by its own bootstraps, or in other words, using one’s own products or services to increase business efficiency. My product controls the process of charging lead-acid batteries from solar panels which gives me free electricity. So to bootstrap my business, I need to use that free [...]

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Julian on May 12th, 2010

The charge controller project has largely exited the design and test phase and entered a production oriented period of activity. However, that doesn’t mean there aren’t any design challenges still to tackle.¬†At each stage of production there are processes that take time, and opportunities exist for the design of production aids or ‘jigs’. One such [...]

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Julian on April 14th, 2010

Too great a compromise. That’s the upshot of trying to use two 5.6 volt zener diodes in series instead of a single 9.1 volt diode. The 9.1 volt has a completely stable reverse voltage over a wide range of current. The 5.1 and 5.6 volt zeners are completely different and have a non-linear current/voltage relationship. [...]

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Julian on April 4th, 2010

Time to have another look at the battery voltage measurement circuit – and in particular the behaviour of the zener diode. The purpose of the zener diode is to shift the relevant range of battery voltages (between 10 and 15 volts) to the 0 to 5 volt range of the PICs analogue to digital converter. [...]

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