Current measurement by telemetry

[ZAxis]

Coming from the Mikrokopter camp we used it's built in telemetry to monitor battery capacity in mAh to judge flight times. With DJI FC we have lost this functionality but want to find an alternative. You can buy current telemetry modules for Spektrum, Jeti and the like. These will monitor overall battery capacity with a single module up to 150A or more but I worry that this module represents a single point of failure, negating the failsafe nature of a dual battery pack. As an alternative I'm looking at a dual sensor setup with one per battery on the dual pack system. It looks as if the Jeti system will allow this whereas Spektrum will not. Has anyone implemented this or have any comment to make?

andy

 

[PeteDee]

Lots of people fly lots of multi's using a single power sensor, very few ever report having any problems. I would think that the risk of having a problem is very low, it is a very mature technology.

Pete

 

[ChrisViperM]

All modules and devices (regardless if built-in or external) to measure mAh usage are not very reliable.....you get a good estimation, but not more....the "Voltage Monitor" feature from Wookong and Naza is useless crap and has led to more problems than doing any good.
I have tried just about any method to avoid a mid-flight LiPo cut-off due to low voltage, and the only reliable product I am using is a LiPo alarm......cost a few $ and doesn't fail:

The actual Voltage under load is about the only relaible indicater to know if it's time to land or not, combined with a decent knowledge of your average flight-times per LiPo pack...

Chris

 

[kloner]

I've flown off mah telemetry telling me when to land for a year now. last spring i built a jib for a guy and put an iosd in it which only has voltage. I can nail 80% better off that voltage gauge easier than looking at a mah gauge. i always land it in a hovering voltage no less than 22.1 and it's dead on....... the extra noise floor of another piece of equipment isn't worth it IMO

 

[Stacky]

I have been using one of these http://www.hobbyking.com/hobbyking/..._2_4Ghz_Telemetry_System_Temp_Amp_add_on.html which goes with one of these http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10343

 

[Efliernz]

I have been using one of these http://www.hobbyking.com/hobbyking/..._2_4Ghz_Telemetry_System_Temp_Amp_add_on.html which goes with one of these http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10343

I too have been using what Stacky has. Individual cell monitored voltage readout (balance plug), total voltage as well as the real-time and total current draw are brilliant. If one cell is failing (as I have experienced twice) the monitor will beep even though the total voltage may be ok. The best insurance $$ I have spent on multi's yet!

Pete

 

[ProPilotWannaBe]

I have tried just about any method to avoid a mid-flight LiPo cut-off due to low voltage, and the only reliable product I am using is a LiPo alarm......cost a few $ and doesn't fail:
The actual Voltage under load is about the only relaible indicater to know if it's time to land or not, combined with a decent knowledge of your average flight-times per LiPo pack...

A couple of months ago I switched over to using the LiPo alarms Chris pointed to... Glad I did!

 

[ZAxis]

OK, thanks for all your input.
I have spoken with Jeti and it is indeed possible to run 2 current monitors at the same time so I will be able to monitor voltage and current drawn for each battery. The voltage will then be monitored by 3 sensors, 2 Jeti + 1 WKM. The Jeti Tx will sound an alarm at one or two levels and the WKM will flash at its preset level so given I can read capacity used along with an alarm on that as well I seem to have all bases covered.

andy