Range Video 2.4 GHz Rx Power Supply?

[Luke]

Hey, quick question... (Figured I'd better ask, before I go and burn something...)

Can the Range Video 2.4 GHz receiver be run directly off a car battery? I seem to remember the thing is rated at 12V +/- 10%, which is just about right, but now I can't seem to find that reference..? (Range Video is selling a different Rx now.)

Has anyone powered the RX this way, and if so, were there any negative effects?

Thanks!

~Luke

[eickst]

I've done it (from a jumpstarter with a cigarette lighter socket) on their 1.3ghz receiver.

I use a regulated supply typically, but I have used lead acid batteries in the past with no problems

[Luke]

Gotcha. Yes, I'd prefer to use regulated supply, but that would mean using an inverter to get 110V off the car battery, and then a transformer, to get 12V DC, regulated. Seems round-about, but I can't (?) just use a 12V voltage regulator on the car battery, since it's only ~12.6V; even an LDO regulator wouldn't be happy on that...

~Luke

[Terry]

I would guess that a car battery would be fine but if it is connected to a car then don't run the engine with it connected. There are voltage spikes and a higher voltage for it to deal with which may be a problem if it was not designed to do so.

Terry

[ThomasScherrer]

yes they run from 9V to 14V

but they get a bit hot at 14V so I suggest you use a little leadacid pack charged from home

then the voltage is in the 12.5 to 13V and that is ok.

a 4Ah or 7Ah will not get lost and will run for many hrs :-)

an old 8 cell NIMH flight pack that can not give 100A anymore, can be used :-)

you see the receivers only draw 150-250mA, but ok enought to heat them up a bit,

but that is normal for all receivers for this frequency range

[eickst]

Actually what I do now is use a 2S lipo and step it up to 12v. I know this seems weird, and the step up converter has about 85-88% efficiency, but I did this because of the amount of 2S lipo batteries that I have and have no use for other than that.

Plus I don't have to lug a SLA 17Ah battery around anymore. A 2S 900mah battery is enough to power the receiver for 5 or 6 hours, even with the loss from step-up. I use the same method on my camera and transmitter as they are 12v and I have a plethora of 2S lipos.

[Luke]

Thanks for the info, sounds like the setup I've got planned will work. I've been using a 3s LiPoly, but I usually fly right next to a car, so plugging into the lighter socket would be more convienent. I did voltmeter the socket, and found that when the car is off, the voltage is right around 12.65V, but on, it spikes up to 13.6V, or so. So, I'll just be careful.

Of course, I could do a step-down-step-up setup, considering how low the current draw is... Use a linear regulator to go down to say, 9V, then step-up to 12V... Would be around 60-70% eff., but.... It would work, right? Eickst, what type of step-up converter do you use?

~Luke

[eickst]

Thanks for the info, sounds like the setup I've got planned will work. I've been using a 3s LiPoly, but I usually fly right next to a car, so plugging into the lighter socket would be more convienent. I did voltmeter the socket, and found that when the car is off, the voltage is right around 12.65V, but on, it spikes up to 13.6V, or so. So, I'll just be careful.

Of course, I could do a step-down-step-up setup, considering how low the current draw is... Use a linear regulator to go down to say, 9V, then step-up to 12V... Would be around 60-70% eff., but.... It would work, right? Eickst, what type of step-up converter do you use?

~Luke

I use a TI PT5041 to step up to 12v. But if you have 12.5 in your car you can use a regulator and avoid stepping it down and stepping it up again. Use a step-up/down converter ie buck-boost and you won't need to convert it twice.

http://www.maxim-ic.com/appnotes.cfm/an_pk/1810

The circuit is for 9V but has an implementation for 12V output.

[Luke]

Or something like this..?

http://www.bphobbies.com/view.asp?id=V7182...15167&img=l

~Luke

[eickst]

Or something like this..?

http://www.bphobbies.com/view.asp?id=V7182...15167&img=l

~Luke

Looking at the datasheet it can only supply 346ma when going from a 13v input to a 12v output. If that's all you need then it should work.

[Luke]

Well, ThomasScherrer posted that the Rx only draws about 150-250 mA... So, cutting it a bit close, but it seems like it would be OK..? (Famous last words.)

~Luke

[W3FJW-Ron]

You could use it like a 723 regulator controlling a larger transister if necessary, however it is sort of an expensive 723....

Well, ThomasScherrer posted that the Rx only draws about 150-250 mA... So, cutting it a bit close, but it seems like it would be OK..? (Famous last words.)

~Luke