RCU Forums - Voltmeter Question

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RE: Voltmeter Question

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ORIGINAL: bruce88123

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ORIGINAL: BadSplice

ok, Im having a hard time wrapping my head around this one.... I went to the battery clinic page about the loaded digital voltmeter, and the idea looked great. Im all set to build one, when it suddenly occours to me.... how is the Voltwatch NOT performing this function already?

I have heard people say that the Voltwatch cant give you a good read of your battery under load... but if its performing the function of a voltmeter, and measuring when the servos are active, isnt that under load? How is loading the battery with a resistor or a lightbulb different than having the radio powered up. In fact, Id kind of think that it would be better, since it would be the exact load of your current radio setup....

so, am I brilliant or am I totally missing something here? [8D]

Missileman hit it on the nose. CONSISTANCY. The voltwatch measures whatever the voltage is at the instant depending on the load which is constantly varying. A constant repeatable load is the BEST way to know what is happening.

Bruce if you are interested in peak load readings, the volt watch is the best. The only thing better would be an O scope, but it's kind of hard to strap one on the side of your plane, and the extention cord screws up the CG. :D

When you get into things like a shutdown of your receiver due to a peak load droping the voltage below the cut off value, a "consistant" load reading isn't going to do you much good. I'm a huge fan of the voltwatchs. If you want a static state reading, just turn on the transmitter and receiver and have a look. If you want a dynamic reading, start moving the sticks. If you want some peak load readings, start stalling out servos while moving the sticks. None of these will give you the real picture of what is happening in the air though but they will give you a clue.

Don

RE: Voltmeter Question

Thanks for the replies guys :)
I can really see where both the variable load reading of the Voltwatch and the constant load of a voltmeter could both be useful. The constant load might give you a better feel for actual battery capacity. It makes sense to me though that if you always checked the Voltwatch under the same conditions (ie. always before flight, or always after flight, or while deflecting one servo, whatever works) that it would give you nearly as consistant a reading as the voltmeter.

RE: Voltmeter Question

The thing about Voltwatch, it is mounted on the airplane and you see how your battery is every time you turn the battery on.
Using a voltmeter you will not, or most people won't, check the battery every flight. If your battery goes bad you may miss it using a Voltmeter simply because you won't check as often as you will with Voltwatch.
Nothing says you can't use both, I do.

RE: Voltmeter Question

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ORIGINAL: Campgems

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ORIGINAL: bruce88123

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I'm not much interested in "Peak readings" on a "flight to flight" basis. I take care of that during setup. I want to see what the battery does under a steady load. If you are worried about voltages "at the RX" to verify wiring and switches and other "stuff" then put an extension in a spare RX connector and feed it to an outside point where you can plug in an ESV. Ya want a Voltwatch? Fine, I have nothing against pretty flashing lights.:D

RE: Voltmeter Question

One of the most valuable facets of the Voltwatch is it's ability to warn you of bad wireing between the battery and the receiver. If you see those light dipping down into the unsafe region when you cycle the sticks, it is warning you that you have a high impedance path between the reciever and battery or something drawing momentary high currents; something the loaded voltmeter will not do. This is especially important for anyone using the new 2.4GHz systems--any brand--as a momentary drop in voltage can cause a dropout of the computer and recovery can take up to 2.5 seconds before the plane is responding properly again.