Julian on March 10th, 2011

It was always my intention to follow up the design of the PWM5 with a MPPT (maximum power point tracking)¬†charge controller. But it hasn’t happened – for a number of reasons. Firstly, there’s a simple economic argument. The 30% or so of extra power that MPPT squeezes out of a solar panel can be obtained [...]

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Julian on February 6th, 2011

The PWM5 is now rated for use with solar panels up to 100 Watts. By upgrading the external diode (the one in the yellow wire) I’ve brought the maximum current handling up to 6 amps. If you look at the label on the back of a 100 Watt solar panel, you’ll see Isc is around [...]

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Julian on November 21st, 2010

I was asked recently if the PWM5 can be used in a 24 volt system. If the 24 volt battery is actually two 12 volt batteries (connected in series) then the answer is a qualified yes. Qualified because this can’t be done with a single solar panel. The diagram shows how it should be configured. [...]

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Julian on September 26th, 2010

I’m very pleased to announce that we’ve just appointed our first overseas sales agent in Brookvale, New South Wales just north of Sydney, Australia. The company is Stern First Pty Ltd, specialists in mobile marine services. They will not only hold stock of the PWM5, but will also supply and fit a complete system including [...]

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Julian on September 26th, 2010

During the summer my solar array expanded a little with the introduction of a new 80W monocrystalline solar panel. I now have around 60 watts of amorphous and 80 watts of silicon. The panels are all connected in parallel inside the box on two chunky aluminium bus bars. A long run of 15A mains twin [...]

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Julian on April 14th, 2010

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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 February 8th, 2010

This is the finished PWM5 Solar Charge Controller

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Julian on January 24th, 2010

Here is the MOSFET circuit including protection and EMC related components. Firstly that innocuous looking 10k resistor connected to the gate of the IRFZ44N MOSFET. This component makes a huge difference to the amount of RFI (Radio Frequency Interference) that the charge controller generates. Together with the FETs own gate capacitance, it slightly increases the rise and [...]

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Julian on September 1st, 2009

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