Using 7.4v. Lipo with flysky rx

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
G-Man

G-Man

Well-Known Member
Messages
1,075
Reaction score
406
Hey Rampage MT guys. Do any of you use a Flysky it4s transmitter and receiver? I have one and want to use a 7.4v lipo to power the rx. Anybody use this setup? Seems my hitec steering servos don't like the 6v nimh hump pack. Thanks
 
G-Man said:
Hey Rampage MT guys. Do any of you use a Flysky it4s transmitter and receiver? I have one and want to use a 7.4v lipo to power the rx. Anybody use this setup? Seems my hitec steering servos don't like the 6v nimh hump pack. Thanks
Click to expand...

I don't have that radio but if you want to use a LIPO to power your RX you should use a BEC and set it to 6v
 
prostock said:
I don't have that radio but if you want to use a LIPO to power your RX you should use a BEC and set it to 6v
Click to expand...
Ya I thought about that. I may get one. But it seems the servos crave higher voltage. My RX states 6.5v max. I can set the kill switch for lipo low voltage shut off. Plus my radio warns me if the rx voltage goes low. I don't know, I have a spare rx if it fries. My steering servos are frustrating me. I run 2 hitec 5765. I swear they are adjusted/synched properly. I get no nimh battery life since swopping The steering quits working 10 minutes into running it.. I used to get at least a tank from the stock ones.Seems some have no problems with them, but I am. That is why I am going to a lipo. Thanks for the input prostock!!
 
G-Man said:
Ya I thought about that. I may get one. But it seems the servos crave higher voltage. My RX states 6.5v max. I can set the kill switch for lipo low voltage shut off. Plus my radio warns me if the rx voltage goes low. I don't know, I have a spare rx if it fries. My steering servos are frustrating me. I run 2 hitec 5765. I swear they are adjusted/synched properly. I get no nimh battery life since swopping The steering quits working 10 minutes into running it.. I used to get at least a tank from the stock ones.Seems some have no problems with them, but I am. That is why I am going to a lipo. Thanks for the input prostock!!
Click to expand...

G-Man you can look into Futaba receivers the new ones are rated for 7.4v http://www.futabarc.com/receivers/surface.html
 
prostock said:
G-Man you can look into Futaba receivers the new ones are rated for 7.4v http://www.futabarc.com/receivers/surface.html
Click to expand...
I emailed Futaba today. They seem to think the Flysky will not work with the Futaba rx. I looked at every rx Flysky has that is compatible with my tx. None of them have have higher than a 6.5v. max. So I either get a bec or throw away my 3 month old radio system for one that is lipo capable. Or and a big OR... Just say screw it and run the lipo directly to the rx. My luck I chose a radio system that is limited. And very limited support, Flysky's phone number is directly to China. What?? No USA sales and service? BS.. I can't get an email response or fb message either.
 
10 mins of run time? That very low!

The issue could be:

1- with the servo themselves
2- steering setup (binding, resistance, restricted steering movement, servos fighting each other.
3- bad battery

Did you tried a different known good battery pack?
 
designed2survive said:
10 mins of run time? That very low!

The issue could be:

1- with the servo themselves
2- steering setup (binding, resistance, restricted steering movement, servos fighting each other.
3- bad battery

Did you tried a different known good battery pack?
Click to expand...
It probably is the servos fighting each other. I have 2 brand new hitec 5765 installed. I did and/ or am having a hard time getting the adjustment down. I got it where it seemed fine ran the truck for 5 minutes and the steering would slow down. Is there any tricks to getting a good adjustment? Funny thing is that the servos don't get hot to the touch when this happens. And my radio warns me of low voltage when I steer. I have 2 2500 mah stock packs. Tried both, same thing happens. So I assumed it was battery power problem. This is why I went lipo. Haven't set it up yet..
 
Well here I am still pulling my hair out. I went to the Lhs and got a castle bec and linked it to my pc to adjust the output voltage to 6 then hooked up the lipo. Installed in the truck loosely to make sure I am good to go. I still have problems. I have no steering or throttle now. Then I remembered that the last time I ran it I had to use the kill switch twice because of it being stuck full throttle. It was fridged that day so I lubed the linkage and it seemed ok. I was more concerned with the steering. Well today the throttle wouldn't move. I put a known new servo in its place and bang throttle now works and the steering works also. I did run through snow that day. Guess it fried the hitec hs 5645 I had in for the throttle. It's 4 months old. Another guess going by how stiff it is to manually turn the servo that it is bound up inside and was just chewing up the battery. I'm not sure if I want another hitec.
 
prostock said:
No problem, here is an article that shows you how to power the servos direct while using the BEC to power your receiver. http://www.fingertechrobotics.com/how-to_servo_voltage.php
Click to expand...
Ok man this article has me back to running again. 1 large steering servo with 7.4v straight from the lipo to the positive lead on the servo, ground and reference wires to channel 1, Castle BEC reducing 7.4v to the 6.5v max. that the rx can handle. New throttle servo also. I took the time to tear each servo down and waterproof them to the best of my ability, and set all the end points. Hopefully my servo problems will be done for awhile. I will be one happy man Saturday when I get the chance to try it out. Thanks to ALL who helped with all the ideas!!!!
 
Do you have any pictures of your set up? I'm looking to do the same thing you are doing but am unsure how everything hooks up. I understand you need to hook positive of each servo to positive battery lead but do you have to solder these in or so they have a connector? Also does the bec go between the battery and rx I'm assuming? And which battery did you go with and did it fit without modifications ? Thanks in advance.
 
fordgtr06 said:
Do you have any pictures of your set up? I'm looking to do the same thing you are doing but am unsure how everything hooks up. I understand you need to hook positive of each servo to positive battery lead but do you have to solder these in or so they have a connector? Also does the bec go between the battery and rx I'm assuming? And which battery did you go with and did it fit without modifications ? Thanks in advance.
Click to expand...
I ran a castle 10 amp bec. Soldered appropriate lead ends onto the bec pos. and neg. wire ends so it can hook to the lipo. On that same solder joint on the bec I ran another separate wire from the positive to the positive on the high voltage servo by gently removing the wire end from the plastic connector. Then soldered a male end on the new wire I ran from the bec slid the two wires together and shrink tubing done there. The other two wires stay in the servo connector and plug into the receiver as usual. Then the bec plugs into the switch which you will have to swop ends to match the bec servo type wire end. The bec needs to be set to your receiver and other servo etc. max voltage using a laptop or a portable programming card they sell. It really wasn't that hard just took me a little bit to get a grip on how I wanted to do it. I will put up a picture
 
No modification. In fact it is smaller. Let me see if I have a wiring picture.
 

Attachments

  • 20170105_174939.webp
    20170105_174939.webp
    46.6 KB · Views: 20
G-Man said:
I ran a castle 10 amp bec. Soldered appropriate lead ends onto the bec pos. and neg. wire ends so it can hook to the lipo. On that same solder joint on the bec I ran another separate wire from the positive to the positive on the high voltage servo by gently removing the wire end from the plastic connector. Then soldered a male end on the new wire I ran from the bec slid the two wires together and shrink tubing done there. The other two wires stay in the servo connector and plug into the receiver as usual. Then the bec plugs into the switch which you will have to swop ends to match the bec servo type wire end. The bec needs to be set to your receiver and other servo etc. max voltage using a laptop or a portable programming card they sell. It really wasn't that hard just took me a little bit to get a grip on how I wanted to do it. I will put up a picture
Click to expand...


Thank you for replying. I think I understand what your saying. Pictures if you had them would confirm what I'm thinking in my mind. And I'm glad the battery will fit with no problems. Thanks again.
 
fordgtr06 said:
Thank you for replying. I think I understand what your saying. Pictures if you had them would confirm what I'm thinking in my mind. And I'm glad the battery will fit with no problems. Thanks again.
Click to expand...
The red wire is direct 7.4v. goes to the positive wire on the high volt servo. The other servo plug goes to the receiver battery input (channel if you wish). This is now regulated down to 6 volts so your receiver isn't over powered.
 

Attachments

  • 20170201_174736.webp
    20170201_174736.webp
    131.4 KB · Views: 14
G-Man said:
The red wire is direct 7.4v. goes to the positive wire on the high volt servo. The other servo plug goes to the receiver battery input (channel if you wish). This is now regulated down to 6 volts so your receiver isn't over powered.
Click to expand...
Forgot to put the lipo in the pic. Here it is..
 

Attachments

  • 20170201_175906.webp
    20170201_175906.webp
    139.5 KB · Views: 19
Back
Top