Wednesday, Apr 21, 2010 at 12:40
"If you use the voltage actually produced by the solar panel * BEFORE * its regulated down to 14.3v it will register @ ~17v and definitely not 14.3v."
Yet again we see a totally erroneous statement.
The Steca solar regulator is, I believe, a PWM shunt regulator. This being the case the solar panel voltage will never be more than a fraction of a volt higher than the battery voltage. Mainey, feel free to prove me wrong by measuring this voltage and showing us.
When in bulk charge mode, the regulator effectively acts as a short circuit between the solar panel and battery.
The voltage before and after the controller will be identical (disregarding switching losses).
When in an output voltage control mode as in equalisation mode, the output voltage will be controlled by SHORT CIRCUITING the solar panel.
I assume this is how the regulator measures the solar panel current,
Mainey's notorious 12Amps. Really has no relevance to the charging current.
Measuring the solar panel voltage at this time will show a voltage less than the battery voltage due to the PWM shunting.
The Steca has a screen display which shows the battery charging current, according to the user manual. ONCE AGAIN I ask Mainey to give us a picture which shows THAT display, as that is the relevant information for calculating efficiency.
This request has been repeatedly ignored.
If we had that figure and the battery voltage, we could calculate the real
power output of his solar system using Joule's law. P=VI.
With regard to the manufacturer's specifications, unless you can measure the solar radiation when making the measurements, you can neither prove nor disprove their figures.
I now withdraw from this thread.
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