Hi folks,
I've fitted a Hobbyking LCD back light to my Turnigy 9X.
I've just left the TX on for 60 minutes to see how much battery consumption was used. It used 1.1 volts.
Not being an electronics man i have no idea if that is good or bad. And i didn't test consumption before fitting the back light!
On the face of it that doesn't seem to bad to me. What do you people out there think?
I want to fully charge my 3s lipo and do the same test again. Then re-charge it and see how many mah were used. However, i want to fit what i think is called an "in-line diode" to reduce the out-put voltage of the lipo first.
Does anyone out there have any knowledge of this??

Here's a thread on it over in radios...
http://www.rcgroups.com/forums/showthread.php?t=1338412

According to Hobbyking, it should draw about 90mA from a 3S battery, so you should see about 90mAH drawn, in addition to what the TX draws, in 60 minutes. If you have a current setting on your voltmeter, it's just a matter of inserting the meter leads in series with on of the two battery wires to get the total current draw: minus from the battery to minus of the TX, for example.

Originally Posted by Wintr

According to Hobbyking, it should draw about 90mA from a 3S battery, so you should see about 90mAH drawn, in addition to what the TX draws, in 60 minutes. If you have a current setting on your voltmeter, it's just a matter of inserting the meter leads in series with on of the two battery wires to get the total current draw: minus from the battery to minus of the TX, for example.

Charged TX lipo, Left TX on for an hour then recharged it.
It used 397mah!!!

Originally Posted by Wintr

According to Hobbyking, it should draw about 90mA from a 3S battery, so you should see about 90mAH drawn

That is totally false information. The leds have a 470 ohm current limiter resistor in line with the leds so according to ohms law it should be maximum of 21mA on 10V and 25mA on 12V assuming the output is shorted. Something like 15mA measured is reported by some folks.

I will measure it tonight.

Hey Guys,

Here is a fairly simple mod to add to your 9X to reduce unneeded current draw from your battery. Add a mini toggle switch in series with the power to the backlight panel. Fits just fine in space next to speaker vent slots near top of transmitter. While I was at it I put in a switch to turn off the speaker ( saved my sanity)

Bill

See pic:

Originally Posted by B12

That is totally false information. The leds have a 470 ohm current limiter resistor in line with the leds so according to ohms law it should be maximum of 21mA on 10V and 25mA on 12V assuming the output is shorted. Something like 15mA measured is reported by some folks.

I will measure it tonight.

I just quoted the listing on HobbyKing's site. Is there only one resistor, or are there a few, operating more than one string? Assuming each string has a 470 ohm resistor, I would guess their numbers indicate three or four strings in parallel.

The standard 9X on 8 NiMh 2300mAh fully charged will power for over 8 hrs till Low voltage alarm sounds.
I have had over 9hrs ... but I work to 8.

Then that is : 287mA rate per hr. (I'm making it simple by assuming alarm is at lowest nominal voltage and use of total mA capacity ... yes its wrong but practical).

Taking mateys 397mA draw over an hour from his battery ...

397 - 287 = 110mA ... which seems to agree with HK .. OK a touch higher ... but lets put that down to errors in Wattmeter calculation of use .. which is a pure maths figure based on reading batts.

Jam1e Do you fly a lot at night? I canīt imagine why anyone would need backlight? apart from night flying or bad eyesight.

Originally Posted by papabearflying

Jam1e Do you fly a lot at night? I canīt imagine why anyone would need backlight? apart from night flying or bad eyesight.

I have the 9X and it is a bit dim to read sometimes, the contrast in the menu is pretty poor range.
But so far after near a year of use - never needed to look at fitting a BL. Neither the Firmware that people rant on about.

It is measured now. Total draw of the Turnigy 9x (ER9X) was 135mA backlight on and 120mA backlight off. This was with 9.6V battery voltage.

So 15mA it is, no more, no less.

Originally Posted by Wintr

I just quoted the listing on HobbyKing's site. Is there only one resistor, or are there a few, operating more than one string? Assuming each string has a 470 ohm resistor, I would guess their numbers indicate three or four strings in parallel.

It has only one resistor feeding two leds.

Originally Posted by B12

It has only one resistor feeding two leds.

Then, clearly, it is not the one here: http://www.hobbyking.com/hobbyking/s...dProduct=17129. The rating there is for several sets of LEDs. Not unheard of for the parts to be different from those advertised, though.

It is the same one but blue color. It has total of two surface mounted leds and one 470ohm surface mount resistor. I kind of know because I have disassembled two backlights for fitting a BS170 mosfet for ER9X control for the light.

And just FYI, different color LED's have very different power consumption, so unless we are comparing same colors, the numbers mean absolutely squat...