Eagletree telemetry in a Savage Flux - RC-Monster Forums

marcus · **Eagletree telemetry in a Savage Flux -** 02.09.2009, 06:20 PM

So, I've been thinking about doing this for a while but "Othello" really added the final piece of inspiration with his telemetry overlay videos.

I got the Eagletree gear I need and am going to install it in my Flux to begin with, to test and get the hang of.

I'll update as I go...............

The V3 logging unit itself has deans connectors on it and you use the device as a passthrough from your battery pack. Using a Hall effect sensor, the current being drawn from the battery is measured and from this power is calculated as well as current, voltage, and cumulative capacity usage

Using Two Temperature sensors for this install, one for the ESC and one for the Motor casing

The Brushless RPM Sensor, there are other methods for measuring RPM but with the kind of rate the motor will be turning at, this is the most reliable

marcus · 02.09.2009, 06:22 PM

Whilst the radio box on a Flux would seem to be the best place for this, the distance from it to the ESC & Motor is too far. The sensors could reach with modification but I just don't fancy the long battery cables I'd have to run to complete the hall effect loop

Instead I cut and mounted a carbon plate to the chassis just adjacent to the motor. From this position it's possible to pick up the battery power without resorting to even a short cable harness having to be made.

Attaching the logger to it with 2xSided tape and tie wraps should be fine. It's yet to be seen what impact the proximity of the motor to the Logger will have heat wise.

skellyo · 02.09.2009, 06:59 PM

Since the wiring on the Flux is set up in series, the setup you have there won't get you a true voltage reading of both packs in series. It should work fine for the current since current is equal in series, but it won't work right for voltage since it's only measuring across a single pack.

marcus · 02.09.2009, 07:07 PM

Yep, you're totally right Skellyo. I'll be using an alternate series harness which kinda sucks because I know how manufacturers love to void warranty for such henious crimes. Oh well....

skellyo · 02.09.2009, 07:14 PM

I've often thought that if you use a series harness to the input of the Eagle Tree, the easiest way to fake out the ESC is to take the output of the Eagle Tree to one of the ESC inputs and just use a Deans jumper across the other input on the ESC.

marcus · 02.09.2009, 07:22 PM

No, the Flux ESC only has 1 Pos & 1 Neg input, unlike the Novak ESC's which have dual inputs and which you can frig like that.
The HPI wiring is perfect until you want to do this particular task. Ho-Hum

skellyo · 02.09.2009, 07:47 PM

Quote:

Originally Posted by marcus

No, the Flux ESC only has 1 Pos & 1 Neg input, unlike the Novak ESC's which have dual inputs and which you can frig like that.
The HPI wiring is perfect until you want to do this particular task. Ho-Hum

It still works the same way though. If you series the packs into the Eagle tree, you have 4-6S input, which goes out of the Eagle Tree as well. Take that output to one of the Deans on the Flux...does not matter which one. Take the other Deans on the Flux and Jumper across it. You have just made it a wire. Now your ESC sees the full voltage output out of the Eagle Tree. Here's a diagram:

marcus · 02.09.2009, 07:58 PM

Ah ya, sorry, see what you mean.

I'd still have to use a series y-harness to feed the Eagletree and frankly, there isn't much room in this area.
I've reduced the number of Deans and cable by converting the Flux to a single Deans which runs right out the Eagletree leaving me only having to use the one Harness to series link the batts.

It would have been nice to leave the Flux as stock though, I would probably have gone with your method had I realised earlier.

skellyo · 02.09.2009, 08:18 PM

Quote:

Originally Posted by marcus

Ah ya, sorry, see what you mean.

I'd still have to use a series y-harness to feed the Eagletree and frankly, there isn't much room in this area.
I've reduced the number of Deans and cable by converting the Flux to a single Deans which runs right out the Eagletree leaving me only having to use the one Harness to series link the batts.

It would have been nice to leave the Flux as stock though, I would probably have gone with your method had I realised earlier.

Either way works. Your way is actually a little less complicated, just makes it so you have to use a separate series harness to run the vehicle. Regardless, it looks like you're ready to go get some data. Now hurry up and go run it.

marcus · 02.09.2009, 09:38 PM

Ended up having to swivel the ESC 90 degrees to allow for cable reach, no biggie.

The RPM sensors I just soldered to the motor output sockets. The instructions called for one of the two wires to be attached, the second being needed in case of problems with the tach reading. Knowing my luck I'd tuck away the second wire and end up needing it so I attached it anyway, it's easier to remove later than to fit.

The ESC temp sensor I squeezed in through a side vent, it's laying against a FET Heat sink so should give a fairly accurate reading

The Motor Heat sensor is in the form of a Lasso which I ran around the motor body

Rather than tuck and hide all the telemetry cables away out of sight, which is normally my style, I left them very accessible. This way I can remove the unit and move it to any other model

Now to see what the software has to offer.................

What's_nitro? · 02.09.2009, 10:07 PM

I think your wiring looks fine.

Let's see some data!!!

MetalMan · 02.10.2009, 12:45 AM

Nice setup! Can't recall seeing someone spend so much time mounting their Eagle Tree data recorder so nice. But it paid off for sure.

Just one thing - telemetry is current-time wireless data acquisition. Looks like what you are doing isn't that, but data recording instead.

marcus · 02.10.2009, 12:53 AM

That is true Metalman, but there is a live function too on the Eagletree, so that kinda lets me squeak in hehehehe

Also, Telemetry doesn't necesarily have to be wireless although it usually is, but yea, definitley Realtime.

marcus · 01:15 AM

So I made a quik test here in my work area. The Flux was sitting on a box spinning the wheels as oppossed to driving.

All works fine, it's certainly quite cool being able to monitor so many parameters at once and seeing how some of them directly interact.

I did notice a failing with the truck straight off though, it's the lipos I have in there. They are cheapy 4000mah 3S but with a poor 15C rating.
You can see the voltage drop away pretty easily under throttle, and that's just spinning its wheels. The 24v at rest reading dropped to around 16v under the gun - yoiks !
Guess I better break out the 25C packs lol

VIDEO

othello · 02.10.2009, 09:35 AM

Glad to see your eagletree setup already at work. Recording of the eagletree software looks perfect (looking forward to see your videos with integrated eagletree data). Your poor lipos already had a very hard workout while only spinning your tires. At 56A voltage droped to 14,8V (2.46V per cell). I'm wondering if you had your lipo cutoff activated (setup properly)? At 6s your setup will require some high quality lipos considering your setup already draws around 30A (500W) while only spinning and accelerating your tires. With good cells holding voltage better max rpm will be around 50000rpm.