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Old 12-27-10, 12:13 PM   #27
strider3700
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Join Date: Dec 2008
Location: Vancouver Island BC
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good point hamster.


Doax I'm using 1 of these Linear BiPolar Hall Effect Current Sensor +/- 80 Amps. I picked up 4 and with shipping they cost less then $30 total if I remember correctly.

I have 2 more that will be going to the hotwater heater probably tonight. And that leaves me 1 more which I haven't decided what to do with yet. I may pick up a couple of the larger ones with the 1/2" openings to monitor power usage on the heat pump. It's got some thick cables running to it.


Last night I took my test cord back and plugged the woodstove in. It only took a couple of minutes with the kilawatt meter to determine voltage, and watts used by the fan then tweak the code in the arduino so that it matches or very close to If I remember kilawatt readings are 42W low, 74W high and the arduino now reads 43W low 74 high by changing the 0.26mV/amp to 0.40 mV/amp. This gave pretty accurate readings across the board from 16-74W but would be way way too low above 500W.

Since you don't move the sensors around easily and my loads are going to be pretty consistent hardcoding that adjustment into a function used just for the woodstove works just fine for me. If I was making this completely generic I could do a table of voltage-conversion factors.
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