ORIGINAL: PZ
Now the first questions I have are regarding the batteries and their use. First of all I would like to knowapproximatelybefore I fly how much flight time would I have with my batteries. Is there a way to calculate this? To know at least an approximate number?
Not exactly but you can develop an approximation. Every battery has an amp/hour rating. for instance, a 2000 mah battery will provide 2 amps or 2000 milliamps of currentfor one hour. You can use the current draw figure from your motor/prop combination to calculate the amount of time you can fly. How much throttle you use affects that, efficiency affects that, limits on the maximum discharge of the battery affects that and so on. So expect only a best case approximation by using the numbers.
With glow engines I simply fly a while and check how much fuel do I still have in the tank and come to an approximate number, but with lipo batteries for example, I should not let them discharge completely because I could damage them so how would I know how much can I fly? also what is the discharge limit?
Lipo batteries change chemically when they reach a point of dischargeof around 3 volts per cell. Going below that can ruin the battery and usually does. You can buy a simple voltmeter that plugs into the balance plug which will read the voltage for each cell. They are about $10.
My second question is in the same area, how much time would it take for my batteries to charge? I will be using 2 x 3200mah 3s batteries in the plane for a 6s config. If it takes much time then I should buy more packs so while I fly, the other packs are recharging and I do not have to wait a long time between flights? Also because I am using 2 batteries should Ipurchasea charger with multiple charging leads to speed up the operation?
Lipo batteries should not be charged faster than 1C or, in the case of your 3S batteries at a rate of no more than 2 amps.. It can take as long as an hour to charge a battery and balance it. I take lots of batteries to the field personally.I never take a charger.I havemore than enough batteries with me to handle the day's flying. You can do it as you like. Many people charge at the field.
Now in another topic is it true that I can not fly the airplane in full power for a long time?
No. What is true is that you can't overheat your electrical components for a long time. As long as your battery and ESC can handle the current draw of the motor and prop without overheating at full throttle, then you can fly that way until you need to replace the batteries. My own habit is to use ESC's that are at least one size bigger than the maximum current draw of the motor prop combination. I use batteries with a high C rating to prevent starving the motor of power. I can fly at any throttle setting I like for as long as the battery has sufficient charge.
Sorry for the long post but I wanted to explain myselfthroughly and thanks for theanswers.
Welcome to electric flight. Hope you enjoy it as much as fuel flight.<br type="_moz" />