Another good reason for telemetry reading each cell.
Actually Pete, I was curious how you were powering the dual BECs in your SU?

What brand?

Budget Zippy 5S 3000mAH 20C. (plane uses 43A WOT)

The Su BEC's are powered off the flight battery. A tap off the main leads to a JST (like smaller batteries have). Then a Y to the BEC's. The JST so I can use a small Lipo for plane RC setup stuff and not need to connect any main/larger battery.

Originally Posted by Maxthrottle

Another good reason for telemetry reading each cell.
Actually Pete, I was curious how you were powering the dual BECs in your SU?

I have a telemetry system from FriSky that does this, however do you realy take your eye off your SU to look at a screen?. Tracking states I have 2 new batterys showing up here today. I hope the same thing doesent happen to these-http://www.hobbyking.com/hobbyking/s...dProduct=24214

FrSky and ER9X you could set an audible alarm, and have the transmitter vibrate in your hands...

(a bit OT, but hey)

hehe.
Even better is the Android apps... send the FRsky via BlueTooth.... to a phone or tablet. And they have voice reporting of what ever you want.
I have all the stuff, but only dabbled in it and haven't got it all working yet. Seeing it works to a laptop (via Bluetooth), but not to my Galaxy S2 ! (there is an issue with certain smart phones Bluetooth capablites - BAH)
Of course you need the FRsky multi cell battery thingy.... I also have all their other add on things... Hub, Alt, Amps, RPM etc... cant even remember what they all are. But fitting them all into a plane could be fun too!
I think the cell volts - best for flight time control - is the main item of use. Then the other 'points of interest' ones, like Amps, Alt, Speed, RPM. Real-time being more use than recording devices - but not needed all the time either.

When I first got the FRsky TX/RX stuff LONG ago, I straight away made up home-made voltage divider doovies (just a 10turn pot and resistor) to report the Lipo voltage back to the TX.... but there is that issue of having to look at the screen! And worse.... the way volts changes with load. Best off just using an alarm on the volts being low I guess.

But I only used it a while and gave up on it, for some reason. It could be fit into any plane of course (8mmx8mmx12mm approx) so I had one for every plane (permanently wired off the ESC plug), even all the 800mm ones. Then eventually cut them all out....
I think it was because the triggering (low volts) was always occuring at 'random' times - according the throttle use of course - even very early in a flight. So it wasn't much use knowing that then.... it was too hard to link any truly useful pattern/point to mean anything of great accuracy use. "Land now? I hits supposedly low volts already within a minute... " but you can fly on to the full timer and only put back way less than max capacity. And Current tests show the plane operating well within battery specs.... so nothing is really technically amiss in the usage.
Maybe I should have set lower volts threshold really.....

The quanum telemetry unit I use has alarms that let you can set thata way your not taking your eyes off the plane, unless an alarm goes off at the setpoint.

I have telemetry built into my Hitec A9. I spent a crap load buying all the gear and gadgets. Tried it in several models and am just not impressed with the functionality. Like everyone is saying how do you watch the screen and the aircraft at the same time? Yes, I can log my flights with post data and that helps but it would be great if one had a flip down HUD on your sun shades to see realtime data and the flight at the same time.

However, connecting up to an Iphone or iPad was really helpful when we fly the larger Turbines and EDF's at the dry lake bed. With an assistant calling the numbers it helps us set up approach and landing speeds with a new model. The A9 does log max flight data so nice to know max current draw, height, speed etc.

The FrSky FAS-100 or FAS-40 (the current sensors) also integrate current, so it'll let you know how many mAh you've used, not just the cell voltage. You can set the radio to say "Joker Fuel" at 4000mAh, and "Bingo Fuel" at 4500mAh if you want. Not through your phone, using the speaker in the transmitter - no second device required

You can also set it to read out certain parameters to you at given intervals, so with the gear down, you might want a speed readout every 10seconds, or above certain throttle settings you might want to know motor temp etc.

It doesn't log though. That would make the Android link valuable alone. I've got a NIB eagletree that I've never used as I've moved to FrSky, but logging would be great.

//Edit: Wow, that sounds like an ad for a radio! All the sensors fit in and around the battery bay, with the Rx at the aft end, BEC in the LEX.

hehe
Yes, that is why I went Android... for the logging. And also the extras it can do too.
All I need is to BUY a very cheap ($100) 7" tablet, seeing my phone wont work!

Hmm, I never looked at any speech in the 9X (ER9X?)... if it is that that can do it.
I only saw the addon speech boards, or the Sky9X which has a ton of other beneficial reasons to be worth having too (at $95).

Maybe the Android way is better as you have a 'player' to go over the records while you are there too? (could use a laptop with any SD card system I guess)

mAh used isn't overly useful, seeing older batteries drop volts before getting to near max capacity. eg a 3000mAH could be unusable in flight by 2000mAH used already - or I have seen even worse cases than that.
Volts.. and preferably per cell.... are probably the most useful.

Rather than a speech readout, or any number etc, probably better is a sliding scale of 'beeping'... like a geiger counter. Very fast beeping being bad! hehe. Do whatever you need to do to REDUCE the beeping rate.... use less power... land ASAP.... etc

Bloody control arm problems.....
I don't quite have useful bits to implement the control arm I need/want on the airbrake pivot shaft. It all moves as planned, but needs a very low/short control arm on that pivot - to stay clear of the battery.
Optimal would have been if I could braze something onto it (metal to metal), to be small and solid. More thinking/planning needed on this part....

I also made the airbrake assembly removable. The airbrake pivot is clamped by a... umm... "clamping pivot bush unit"... so you can unbolt that and release the airbrake assembly from the hatch.
I forget exactly why I planned for that.... it seemed a useful idea...

And I got all my "Su-35 paints" (Acrylics) matched up, so I have the set for repairing/painting the plane now.
Airbrushing.......

Pete,

Isn't 3ah 20c pack only going to deliver 60 max ? So if you were pushing it and had a cell acting up then it very well could have been implemented by the combo of both, bad cell and asking for 60a when the pack only had 2.5ah or less left in it

Originally Posted by v8truckin

Pete,

Isn't 3ah 20c pack only going to deliver 60 max ? So if you were pushing it and had a cell acting up then it very well could have been implemented by the combo of both, bad cell and asking for 60a when the pack only had 2.5ah or less left in it

So, I guess trying to save a buck on batterys is a bad idea?

Originally Posted by PeterVRC

Bloody control arm problems.....
I don't quite have useful bits to implement the control arm I need/want on the airbrake pivot shaft. It all moves as planned, but needs a very low/short control arm on that pivot - to stay clear of the battery.
Optimal would have been if I could braze something onto it (metal to metal), to be small and solid. More thinking/planning needed on this part....

I also made the airbrake assembly removable. The airbrake pivot is clamped by a... umm... "clamping pivot bush unit"... so you can unbolt that and release the airbrake assembly from the hatch.
I forget exactly why I planned for that.... it seemed a useful idea...

And I got all my "Su-35 paints" (Acrylics) matched up, so I have the set for repairing/painting the plane now.
Airbrushing.......

I see the weather you folks in OZ have. I bet your paint will dry fast in 130 degree heat!