Hello everyone. First - this is my first post, and this weekend (including today) marks my first flight(s)!
I'm thrilled, and having fun (mostly). Here's my first ever flight: (then my question)
Now, my question:
It would seem that every time the main battery gets low (I'm running two - one for AMP2 & receiver, and 4S for ESCs/motors) one of the props quits sending the copter into a death spin. I've been fortunate that only a prop & gear has busted on my two hard "landings" - but I can't believe that the proper behavior for low voltage is a death flip (one motor stopping).
So - can you help? Is there an audible alarm anyone has rigged for low voltage - i.e LAND NOW! ??
Thanks in advance for all the guidance paid forward and all to be received!
Cheers, jake in Sonoma County, CA
Comments
I can recommend collecting data about power consumption:
1) If your transmitter has a timer, program it so that it activates whenever the throttle is raised over a threshold.
If your tx does not have a timer, keep flight time manually. Or you could probably retrieve it from the logs.
Write down your flight time when you take the battery of the copter to recharge it.
2) After charging the battery, write down how much power the charger put into it for that flying session.
3) Put the data into a spreadsheet and have the spreadsheet divide your power used by your flight time. That gives you your power used per minute. Have the spreadsheet divide your battery's capacity by that value. The result is your flying time for the battery. Do a few of these recordings / calculations to get an average value, and use that as a limit for your flying time, with a bit of safety margin.
This is all very helpful - thank you. Mike, I appreciate the lesson in appropriate posting, too... I'll be sure to comply better in the future :-)
John, that sounds like my hot ticket.
I have telemetry in my hands, the new 3DR air & ground boards, but haven't had time to configure & learn it yet. I also should disclaim that I'm as green as they come here - learning fast & excited about all that's left to come. As far as ease of getting it in the air and flying is concerned, the APM2 & 3DR quad has worked great, and I know of the *mountain* of documentation I've only just scratched the surface.
My ESCs are the 3DR 20Amp bits. I clearly have some reading up to do on those, as well now. Thanks everyone. Here is another video I made yesterday: ~jake
#1 Program all of your ESCs to NIMH mode. Then turn LVC (low voltage cutoff) to OFF.
#2 Add a voltage alarm.
Most ESCs dont allow you to turn LVC off when used with LiPos so you have make them think youre using NiMH batteries. Once you change that, you can turn LVC off. This will keep your motors spinning until the battery is completely dead, it might kill your battery but it will keep surprise motor cut-off from happening.
What you are explaining the problem is very simple,Mike mentioned to you...your ESc is not calibrated the same way,one or more of them is programed to low voltage cut off wich means it will stop working,shut down...
In the future, please ask questions in the forums. The forums are better suited to threaded discussions, so you can get better help there, other people can search for answers to similar problems, and it is also part of the site blog guidelines.
Congratulations on your first flight. I hope there are many exciting firsts and unexciting follow on events for you.
By the way, your question is discussed in the manual here and and there are a few places on the site and in various manuals that cheap lipo buzzers are recommended. There are also some blogs here that talk you through setting up LED displays to warn you of the battery status, do some searches. You'll find articles like this one to flash some LEDs and similar projects and howtos. The lipo battery *buzzer* is a cheap way to go, if you're flying near your hearing, the sensors are good if you are working with a ground station, and the LEDs work in other situations.
Happy hacking. Oh, and you should examine the settings for your ESCs. Each ESC maker has their own error codes and settings. For multicopter use, you generally want to change the default low voltage cutout setting. It is often to set to shutdown... suitable for some fixed wings, but never suitable for a multiroter. But be sure to read about what can happen if you run your lipo so low that this becomes a problem. These toys are not consumer-grade. You can damage your toys, and yourself, and others, with this stuff, so be sure to read and know how to maintain your gear.
@Jake you can get a low voltage alarm that plugs into the balance port. It makes a really loud alarm. However, prevention is better than cure. Being able to monitor amp usage and voltage is even better. You can get a tx with telemetry or a Quanum telemetry system with amp meter can be added to any TX/RX system.