On 7/1/03 13:22, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote:
> Notice that it took 60 minutes to drop from 10.9 to 9.9 (0.0017 volt/min) > 120 minutes from 9.9 to 9.8 (0.0008 volt/min) > 100 minutes from 9.8 to 9.7 (0.001 volt/min) > 42 minutes from 9.7 to 9.5 (0.005 volt/min) > 38 minutes from 9.5 to 9.0 (0.013 volt/min) > 20 minutes from 9.0 to 8.5 (0.025 volt/min) > > SO now we take a BC6 see what color corresponds to the voltages shown above > and we have an idea of where to worry about finding the gas station. I think you missed the point. The various on board devices are ONLY useful at the end of the curve. You might determine that the last green light (in my curve) corresponded to 9.8 volts. But since it sits at 9.8 volts for 100 minutes it tells you nothing about how long you can fly, unless you catch it at the instant that it came on. A lot will depend on what voltage the first yellow comes on at. But even then, you could take off with a green and go yellow at the instant you released for the launch. I keep saying this and somehow cannot get my point across, battery voltage alone is absolutely meaningless when it comes to determining remaining flight time unless you are already at a critical voltage (1.1 or 1.0 volts per cell). The only reliable way I know of is to determine your average consumption and then TIME your flight. Battery voltage checking then only becomes a means of making sure that the battery is still working. Not as sexy as a nifty thingy in your plane with lights and such, but it works without question. They are useful in telling you that you are dead, but useless at telling how far you have to go if you are not yet fully dead (battery wise that is). Even knowing the transient low voltage recorded during a flight is not really all that useful. Kind of interesting, but not very important. Now if you can develop a curve like the one I posted for my TX battery you can then start to use voltage, but you still need the time element since without it you cannot place yourself on the curve. A device that would allow you to load the curve data into it and then keep track of time for you would start to get us to where we want to be. But I still find it far easier to cycle my battery, determine the average consumption and then simply time it from there. Way too easy and it is specific to my battery in that plane under my usual flight conditions. ~~~~~~~~~~~~~~~ Bill Malvey RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
