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Average current draw from 2.4 transmitter

PostPosted: Fri Feb 04, 2011 10:24 pm
by S-rob
Hi there. whats the average (ball park) current draw for a 2.4Ghz transmitter ??
both, say 6v Spektrum & 12v Turnigy/generic

I want to setup a bench test of my NimH's AA's using my chargers discharge function (which can display maH discharged )
I have a few different AA's I want to test, after the dismal actual run-time of my 2800's.
Im back to using Alkalines, as various nimh just dont last in my 6v TX .


Re: Average current draw from 2.4 transmitter

PostPosted: Tue Feb 08, 2011 10:55 pm
by RCModelReviews
The current-draw of a transmitter depends on several things but mainly, the type of regulators it uses.

Some systems use linear regulators, some use switch-mode regulators.

The former will draw more current than the latter -- sometimes a lot more.

A good example are the current DSSS modules from Corona. They have a linear regulator so they have quite a high current draw. By comparison, the FrSky modules have a switch-mode regulator so they draw less than half the current.

The same goes with the transmitters themselves -- those with switch-mode regulators will draw less than those with linear ones.

I haven't done a head-to-head comparison but I do know that the days when you only got 60-90 minutes from your transmitter from a full charge are gone. Most 2.4GHz systems will give many hours of flying (especially if they have a lithium pack). I charge my own 9X only once a month at most -- and I tend to fly a lot when I can.

My JR 9XII (9303) now gets twice the time per charge since I replaced the JR 72MHz synth module with a FrSky 2.4Ghz module. That's partly because the 2.4GHz systems don't need so much power (100mW versus over 500mW) and partly because the FrSky has a switch-mode regulator.

A good way to tell if *your* 2.4GHz system has a switched or linear regulator is to feel the module or the back of the case. If it's getting warm after extended use then it's probably got a linear regulator. Switch-mode regulators should run cool because they're not wasting power in the way the linear ones do.

Re: Average current draw from 2.4 transmitter

PostPosted: Sat Feb 12, 2011 2:39 am
by Kamu
Is switching linear to switch mode a difficult task?
Perhaps a potential video to add to your ambitious todo list :)...