Originally posted by xviper2
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Correct about the integrated BECs. Don't be too concerned about your RX voltage. There are 2 internal BECs providing power to the RX on this plane. If one fails, the other "should" continue to power the RX. Unless you have a complete ESC failure on both ESCs on this plane, the RX will still draw sufficient power to do a "dead stick" landing even if there's not enough juice to power the motors. Internal BECs are nothing magical. They draw current from the main power coming in to the ESCs. Voltage drop at the RX will be the last thing you'll see happen if the main batteries get low. No point in watching it. Of course, you can always go for externally powered external BEC. One is all you need. These are usually powered by a 2 cell battery and is plugged into any unused channel on the RX or even into a "Y" with some servo.
Also, don't concern yourself so much with flight battery voltage. I try to land while the main batteries are still near storage voltage of about 3.75v/cell. This involves some trial and error. Start on the safe side and set your timer for 5 minutes for this plane. When you land, immediately check the batteries. If you still have lots of juice left, add a minute to the next flight and continue to do this until such a time that your batteries come down at the desired voltage. If you fly particularly high throttle on a given flight, then mentally deduct some time off your flight and land before the timer goes off. You can set your ESCs at whatever low voltage cut-off you like but don't fly till that happens. You also dial in what kind of cut-off you'd like ---- soft or hard. SOFT will get you a rapid decline in motor response while HARD will just cause your motors to simply stop. You can generally get a few more seconds if you shut the throttle down and give the batteries a little time to come back, then try the throttle again for another short burst. If you are low to the ground at the time, this will be of no use.
Now, if you're really worried about battery voltage while flying, you can utilize one of a couple of devices that will give you some warning. One type is the loud buzzer that you attach to the balance port of one battery. Get 2 if you want one on each. They cost about 3 to 5 bucks each.
Another alternative is to get one or two of those remote pagers that vibrate when the battery gets to a set voltage. HobbyKing used to sell them but they were finicky at times so they don't carry them anymore and I stopped using them because always forgot to turn the pager on. I know of buddies who use both types of devices and they seem to like them fine. Personally, I just fly by time. I think most people fly by time.
When I'm really concerned about RX power (on expensive planes), I go with something like this:
This does nothing till RX voltage is low or zero and it cuts in automatically so you can dead stick it. Peace of mind and cheap. Just remember to turn it on so it can monitor things.
Also, don't concern yourself so much with flight battery voltage. I try to land while the main batteries are still near storage voltage of about 3.75v/cell. This involves some trial and error. Start on the safe side and set your timer for 5 minutes for this plane. When you land, immediately check the batteries. If you still have lots of juice left, add a minute to the next flight and continue to do this until such a time that your batteries come down at the desired voltage. If you fly particularly high throttle on a given flight, then mentally deduct some time off your flight and land before the timer goes off. You can set your ESCs at whatever low voltage cut-off you like but don't fly till that happens. You also dial in what kind of cut-off you'd like ---- soft or hard. SOFT will get you a rapid decline in motor response while HARD will just cause your motors to simply stop. You can generally get a few more seconds if you shut the throttle down and give the batteries a little time to come back, then try the throttle again for another short burst. If you are low to the ground at the time, this will be of no use.
Now, if you're really worried about battery voltage while flying, you can utilize one of a couple of devices that will give you some warning. One type is the loud buzzer that you attach to the balance port of one battery. Get 2 if you want one on each. They cost about 3 to 5 bucks each.
Another alternative is to get one or two of those remote pagers that vibrate when the battery gets to a set voltage. HobbyKing used to sell them but they were finicky at times so they don't carry them anymore and I stopped using them because always forgot to turn the pager on. I know of buddies who use both types of devices and they seem to like them fine. Personally, I just fly by time. I think most people fly by time.
When I'm really concerned about RX power (on expensive planes), I go with something like this:
This does nothing till RX voltage is low or zero and it cuts in automatically so you can dead stick it. Peace of mind and cheap. Just remember to turn it on so it can monitor things.
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