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Old 08-01-2009, 09:12 PM
Hoppy Hoppy is offline
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Join Date: Sep 2008
Posts: 241
Originally Posted by witsend View Post
OK this is how I would suggest the test be conducted if there are no storage scope meters available.

Set the duty cycle and check the temperature of the resistor when it's stable.

Then apply the same resistor to a variable power supply and adjust the voltage until the same temperature is found and stable over the same resistor

Then do a v^2/r analysis to determine the wattage dissipated at the start of the experiment.

Then record the start time to run the experiment until the battery is depleted to say, 11 volts from a 12volt supply or 22 volts from a 24 volt supply.

Then recharge the batteries and apply a resistor in series with them to draw down the same amperage as recorded at the start of the experimental test.

Then record the time it takes for the battery to deplete to the same level as the experiment.

Then rerun both tests.

If you've got two sets of batteries - run them concurrently until one or other hits that critical voltage level. Then recharge both and swap them, control to experiment and vice versa.

Please comment if I've left out anything critical.
Yes, re-run test as many times as necessary until calculated COP stops falling and stabilises out!