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Measuring Power System Max Watts?

Old 01-27-2009, 04:48 PM
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Buck Rogers
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Default Measuring Power System Max Watts?

When measuring the max watts of a power system what does everyone assume as the state of the battery?

Is it better to measure max watts using a fully charged battery or is it better to use a partially discharged battery assuming that the Voltage (and hence amp and watts) will drop to a nominal level after a bit of use?
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Old 01-27-2009, 04:55 PM
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gfdengine204
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I always use a fully charged battery. I always start my flights with a fully charged pack. If you don't use a fully charged pack to test, you won't see max wattage and could have problems later.
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Old 01-27-2009, 05:08 PM
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Buck Rogers
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My thinking is that the voltage drop on a fully charged battery can be quite steep in the first minute or so and then it levels out. You could probably over prop slightly to allow for this so you can full power when the battery is nearer its nominal voltage.
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Old 01-27-2009, 06:08 PM
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slipstick
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If you're desparate to get a little more power you should buy a bigger motor/ESC/battery etc. If you constantly run your equipment right up to and past the edge of the specification you will find this hobby gets very expensive.

Maximum power is obtained with the highest voltage. That's when the battery is fresh. If you wait until the voltage drops before measuring you know that the power is going to be higher in the early part of the flight. So the spec says you can use 300W and you're going out of your way to exceed that limit.

Your choice but it's not something I'd do.

Steve
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Old 01-28-2009, 04:27 PM
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Walt Thyng
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Most reliable testers start with a fully charged battery and run whatever system they are checking for 5-10 seconds before starting measurements. The really good ones also let the pack cool after charging.
In my opinion, the only way your can get reliable, repeatable results is to use the above process.
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