Gday Troy
Quote:
Originally Posted by AndrewJ http://www.iceinspace.com.au/forum/....s/viewpost.gif
PWM controllers allow you unlimited power levels ( almost ), can be easily converted into thermostatically controlled units ( so they only heat when required, thus preserving yr batteries )
Does this mean you could, knowing the dew point, set a temperature somehow on the controller at which the heater would kick in? Any pointers in the right direction for that?
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Sort of.
"YOU" dont need to know the dew point.
( and it changes over time anyway )
There are 2 basic ways to run a thermostatic heater
1) Keep corrector just hotter than ambient ( easy )
2) Keep corrector just above dew point ( harder )
I have made 2 types, one passive ( ie no PIC used ) and one PIC based
For the first, you set a temp differential, and the heater comes on only when reqd, and keeps the corrector X degrees above ambient.
This is simple to do but may heat when not reqd.
The Dewpoint version is more complicated ( and really needs a PIC controller ), as it has to measure relative humidity, and then calc dewpoint, and ensures the corrector stays X degrees above dewpoint.
The latter involves more calculations, but saves power as the heater is only used when absolutely necessary
For general use, just staying 1 to 2 deg above ambient is sufficient.
There are many ways to do this
Andrew