Powering nitro aircraft with Spektrum receiver

[Spurr]

Question: What is the easiest way to power my receiver?
Application: 4-channel nitro J3 Cub
Equipment on hand for my project: Spektrum AR636 6-channel receiver and Spektrum DX6 transmitter

I'm having trouble understanding how to power my Spektrum receiver. I started out with a 4.8V NMH because the published input voltage range is 3.5 to 9.6V. Got it to bind OK but then no light on the receiver. One club member said I need at least 5V to power my receiver. Then he said consider using an 11.1V LiPo with a 5V BEC between battery and receiver. I quickly realized I needed a male MOLEX connector for the female MOLEX balance battery lead. Trying to find 3S male MOLEX connections is much like looking for some "unobtanium." :confused:
Can't wait to hear from some RKPs (Really Knowledgeable Person)!

[xviper]

You don't need to use the balance plug on your battery to tap for power. You can use the main power leads from any 2s or 3a LiPo battery and plug that into an external BEC and from that, plug it into the RX into any unused port or even into a "Y" if you don't have an empty port.
Here is what I've used in the past with some planes. Note that I'm using this set-up to powering a servo test, but the end that goes into the tester is the same end that goes into your RX. I'm using a 2200mah, 3s LiPo but you can use a 2s or 3s with anything around 1000mah, more or less. The BEC will scale down the voltage to what the RX needs.

[Spurr]

Xviper, Thank you so much for your post! The smallest LiPo I have is 7.4V, 1500mAh, 2S. I bought them by mistake awhile ago. Still holding a storage charge. Will they provide enough power after going through the 5V BEC? No problem now with connections. Nice Christmas present for me!

[xviper]

Xviper, Thank you so much for your post! The smallest LiPo I have is 7.4V, 1500mAh, 2S. I bought them by mistake awhile ago. Still holding a storage charge. Will they provide enough power after going through the 5V BEC? No problem now with connections. Nice Christmas present for me!

That LiPo will work. The BEC needs only 5V, so a 2s battery when fully charged will put out 8.4v. Just monitor the amount of juice it uses for one flight so you know how many flights you can do before you need to charge it back up. Don't let it get below about 3.8v/cell before charging.

[Spurr]

Xviper, again thank you for your most excellent reply!

[Jawbreaker169]

Good day all,
i have an AR636 that I want to install in this nitro plane in the attached photo. I have installed many in my foamy electrics with no issues… difference now is port #1 would now occupied by the throttle servo so where would the battery plug into, since there is no esc with nitro to power up the receiver through the ESC 🤷🏻♂️🤔
I was talking to some guy and he said that I should plug it into the bind Port. I tried that but the receiver didn’t light up like there wasn’t enough power or something and I just took the battery off the charger and tested it so I know it was fully charged. If I can get some help soon I might get this baby in the air.


looking forward to some helpful replies God bless you all see you in flight soon.

[xviper]

Good day all,
i have an AR636 that I want to install in this nitro plane in the attached photo. I have installed many in my foamy electrics with no issues… difference now is port #1 would now occupied by the throttle servo so where would the battery plug into, since there is no esc with nitro to power up the receiver through the ESC 🤷🏻♂️🤔
I was talking to some guy and he said that I should plug it into the bind Port. I tried that but the receiver didn’t light up like there wasn’t enough power or something and I just took the battery off the charger and tested it so I know it was fully charged. If I can get some help soon I might get this baby in the air.


looking forward to some helpful replies God bless you all see you in flight soon.

Most Spektrum RXs, the bind port is also the battery port. However, that is inconsequential as a BEC can be "Y'd" into any port. Ensure polarity is correct. If polarity is reversed, nothing will happen.
PS. Just so we're on the same page, when you say "battery", what kind of battery are you talking about - type, cells, volts? Meaning, you are not using an external BEC but a battery straight into the RX? The RX can only accept so many volts.

[Jawbreaker169]

Yes

[Jawbreaker169]

The strange thing is the receiver lights up and works perfectly when it switched to an ESC but when I try to plug-in a battery not using the ESC it won’t light up at all🤷🏻♂️…… I try to power it up with a Futaba nr-4qb battery and nothing!
I had originally plugged it into the binding port on the receiver and I got nothing….. so then I plugged it into the #1 slot where the ESC plug goes to control the throttle and nothing either!
So now I’m really confused I cannot use any of my other batteries because they’re too big I don’t have anything 5 volts everything I have is 11 volts or higher

[xviper]

The strange thing is the receiver lights up and works perfectly when it switched to an ESC but when I try to plug-in a battery not using the ESC it won’t light up at all🤷🏻♂️…… I try to power it up with a Futaba nr-4qb battery and nothing!
I had originally plugged it into the binding port on the receiver and I got nothing….. so then I plugged it into the #1 slot where the ESC plug goes to control the throttle and nothing either!
So now I’m really confused I cannot use any of my other batteries because they’re too big I don’t have anything 5 volts everything I have is 11 volts or higher

That's probably why it isn't working. These RXs can't handle 11 volts. You may burn it out. You need to get something like a LiFe battery or get an external BEC that is powered by any of your 11V batteries. The external BEC will scale it down to something the RX can function on. That's what the internal BEC of your ESC does. It scales it down. You need to see what the working range of the RX is. It's going to be in the 6V area.

[Jawbreaker169]

I think you misunderstood me I’m aware of that fact I’m aware that this receiver can only receive 5 V max!
I was simply informing you that all the rest of my batteries in my fleet are all 11 V or greater and they’re all 3-4&6 cell so unfortunately I would not be able to utilize those batteries for this plane. Which is exactly why I was using the 5 V Futaba radio battery that I used to use on my 72 MHz and what I use on my RC boat.
I left it on till it was fully charged I put it on my battery tester adjusted the tester for NiCad and it registers 100% charged which is why I cannot understand why it will not fire up this receiver.
The only time this receiver has ever seen an 11 V battery is when it was connected through an ESC!
Now, I did look up the item you mentioned(bec) and this is what I found. Maxmoral 1-Pack External 5V 3A UBEC Voltage Regulator Support 2S-5S Receiver Power Supply for RC Airplane Aircraft!
back in the day when I worked at hobby shack all my nitro planes ran on the Futaba battery that I am trying to use now maybe these new spectrum receivers don’t like the amperage on that battery and would require this set up is this what you’re suggesting that I utilize? I have a 3S 650 mA which is a very small compact battery which would probably work very well with this BEC if you give me the yes I’m gonna order it right now! I just hope that it solves my problem.
what sucks is I took everything apart pulled out one of my power packs from one of my former planes connected the battery to it plugged into this receiver and it fires up no problem so maybe this is the solution to the problem!

in any case I want to tell you thank you from the bottom of my heart for all this information it’s been along time since I’ve been in this hobby it’s good to know that there are still some good hearted people out there that want to help a fellow flyer to you sir I am grateful and you have a cool call sign!

[xviper]

The only time this receiver has ever seen an 11 V battery is when it was connected through an ESC!

Now, I did look up the item you mentioned(bec) and this is what I found. Maxmoral 1-Pack External 5V 3A UBEC Voltage Regulator Support 2S-5S Receiver Power Supply for RC Airplane Aircraft!

I have a 3S 650 mA which is a very small compact battery which would probably work very well with this BEC if you give me the yes I’m gonna order it right now! I just hope that it solves my problem.

in any case I want to tell you thank you from the bottom of my heart for all this information it’s been along time since I’ve been in this hobby it’s good to know that there are still some good hearted people out there that want to help a fellow flyer to you sir I am grateful and you have a cool call sign!

I’ll address each of the above points.
Your receiver should not have seen 11v when powered via that ESC since the internal BEC in it scaled the voltage down to about 5v to 6v.

I’m not familiar with the Maximoral. My worry is that 3A may not be enough to adequately power all the servos that might be working at one time. The typical SBEC (switching) in an ESC is minimum 5A and is usually more. A 3S 650mah battery should be enough to power a BEC in your plane for 2 to 4 or more flights, depending on how long the flights are (typically 10 to 20 min for a nitro) and how much servo draw there is and whether or not you’ve got lights involved.

[pumkin]

I just bought the GP Avistar and also have the AR 631 receiver, I would like to install this and set up safe and AS3X if possible, can't find any info on this-thanks for the help.

[xviper]

I just bought the GP Avistar and also have the AR 631 receiver, I would like to install this and set up safe and AS3X if possible, can't find any info on this-thanks for the help.

Did you scan the product page for the AR631? On that page, you will see a video on programming the 637T, which is the same procedure for doing a 631. That video is only "Chapter 1". View the video on YouTube and you'll see all the other chapters.

https://www.horizonhobby.com/product/ar631-dsmx-6-channel-as3x-and-safe--receiver/SPMAR631.html