Can I get the higher voltage and ampere by wiring modification on futaba port?

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aav514
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Can I get the higher voltage and ampere by wiring modification on futaba port?

Post by aav514 » Mon Sep 25, 2017 5:52 am

hi,

Can I get the higher voltage and ampere by wiring modification on futaba port?


I attached the 2.4Ghz 3000mW radio amplifier on my 9xr pro.

the amplifier ask at least 5V /2A, support 5V~16V external power source.


but I want to use futaba port of 9xr pro, as a power source of amplifier.

how much voltage and ampere can support on futaba port? 5V / 1.5A ??

But That is a little bit insufficient voltage and ampere .


Of course, I can connect wire to battery directly with futaba port.

but if I modifiy like that, amplifier would always be ON, regardless the state of the power switch of 9XR.

I want to make it works according to the status of 9XR switch.

so, connect wire to battery directly with futaba port is not a good idea.


Can I get the higher voltage and ampere by wiring modification?

Does anyone have a good idea about power output modification on futaba port?

Please help me.

Thank you in advance for your support.
Last edited by aav514 on Mon Sep 25, 2017 12:56 pm, edited 2 times in total.

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MikeB
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Re: Can I get the higher voltage and amphre by wiring modification on futaba port?

Post by MikeB » Mon Sep 25, 2017 8:08 am

The power connection on the Futaba port is basically battery voltage, but is switched via the power switch.
However, the battery connects via a FUSE (FU1 type 170F), a current measuring resistor (R9 0.1ohm, 0.25W and a diode (D4 type SS34).
The diode is rated at 3A.
R9 measures the TOTAL current drawn from the battery. At 0.25W rting, this limits the total currect to 1.58A.
I'll need to check the rating of the fuse. A quick check suggested 170mA, but this seems to be too low for the radio.

Mike.
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aav514
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Re: Can I get the higher voltage and amphre by wiring modification on futaba port?

Post by aav514 » Mon Sep 25, 2017 1:24 pm

MikeB wrote:
Mon Sep 25, 2017 8:08 am
The power connection on the Futaba port is basically battery voltage, but is switched via the power switch.
However, the battery connects via a FUSE (FU1 type 170F), a current measuring resistor (R9 0.1ohm, 0.25W and a diode (D4 type SS34).
The diode is rated at 3A.
R9 measures the TOTAL current drawn from the battery. At 0.25W rting, this limits the total currect to 1.58A.
I'll need to check the rating of the fuse. A quick check suggested 170mA, but this seems to be too low for the radio.

Mike.
Hi, Mike

Thank you for your answer.

Problems about voltage and switch state has been solved.
but ampere problem not solved yet.

5V, 2A , 10W
3 cell lipo 11.1V , 1.58A, 17.538W
I think this might be ok.

If I replaced the fuse, I could get higher ampere output on futaba port?

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MikeB
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Re: Can I get the higher voltage and ampere by wiring modification on futaba port?

Post by MikeB » Mon Sep 25, 2017 2:35 pm

Checking further (without taking a 'PRO apart to look at the fuse), I think the fuse is a FVT170F, which is rated at 1.7A.

The radio takes up to 200mA, peaking rather higher when voice output is taking place, so for R9 to be OK, I would limit the current taken from the Futaba socket to around 1.2A. Note you will lose around 0.6V in diode D4, with over 0.1V lost in R9, so the voltage at the socket may well be 0.8V (allowing for wiring losses as well), lower than the battery voltage.
I don't know what the power switch is rated at.

I might also question if a 3W output at 2.4GHz is legal!

Mike.
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jhsa
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Re: Can I get the higher voltage and ampere by wiring modification on futaba port?

Post by jhsa » Mon Sep 25, 2017 4:10 pm

Did he say it was 2.4Ghz?? :)
But I believe 3W might be illegal in any frequency, pretty much anywhere in the world and surroundings, unless you work for the military or NASA.. ;) :mrgreen:

About the switch, seeing my radio's switch fail as its contacts became completely black with normal operation of the radio during about 2 years of operation, I would suggest not to load it with anymore than what the radio already takes.
Using that switch without the aid of some electronics, at more than 1 ampere, it is just a matter of when it will fail, not if it will fail. That in my opinion is asking for trouble... Big trouble.. :)

João

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ShowMaster
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Re: Can I get the higher voltage and ampere by wiring modification on futaba port?

Post by ShowMaster » Fri Sep 29, 2017 7:02 am

I’m not sure I would want 3w at 2.4g close to my face and eyes if the antenna is on the case?

Quote from the Cisco Wireless Safety warning.
Do not hold any component containing a radio such that the antenna is very close to or touching any exposed parts of the body, especially the face or eyes, while transmitting.





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aav514
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Re: Can I get the higher voltage and ampere by wiring modification on futaba port?

Post by aav514 » Fri Sep 29, 2017 6:01 pm

MikeB wrote:
Mon Sep 25, 2017 2:35 pm
Checking further (without taking a 'PRO apart to look at the fuse), I think the fuse is a FVT170F, which is rated at 1.7A.

The radio takes up to 200mA, peaking rather higher when voice output is taking place, so for R9 to be OK, I would limit the current taken from the Futaba socket to around 1.2A. Note you will lose around 0.6V in diode D4, with over 0.1V lost in R9, so the voltage at the socket may well be 0.8V (allowing for wiring losses as well), lower than the battery voltage.
I don't know what the power switch is rated at.

I might also question if a 3W output at 2.4GHz is legal!

Mike.
thank you, mike
it works well

amplifier was made in china, 3 watt output maybe not a actual performance.

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