7.4v for Rx

[chinslip]

hi again. I'm looking at upgrading my servos and Rx battery to 7.4v lipo. I am getting 7.4v servos but dont know if my Rx can handle the 7.4v. Any ideas?

 

[BrianBrownlee]

hi again. I'm looking at upgrading my servos and Rx battery to 7.4v lipo. I am getting 7.4v servos but dont know if my Rx can handle the 7.4v. Any ideas?

what’s the make and model of the radio system?

 

[chinslip]

what’s the make and model of the radio system?

Right, that would help. Futaba 3pm fasst. The receiver has an operating limit of 6v.

 

[BrianBrownlee]

Use the same fasst system and I use lipos and or life bats ... but with the use of a voltage regulator... never had a problem.. super long bat life like days of use lol and well it puts out the 6v and the average boat works fine off of 6v servos or 7.4 cut down.. too.. if the linkage and torque are great enough for the rudder job

 

[chinslip]

Use the same fasst system and I use lipos and or life bats ... but with the use of a voltage regulator... never had a problem.. super long bat life like days of use lol and well it puts out the 6v and the average boat works fine off of 6v servos or 7.4 cut down.. too.. if the linkage and torque are great enough for the rudder job

thanks for the info. will get li-fe bats

 

[RaceMechaniX]

Futaba receivers are OK to use 7.4 2S lipos directly. Hopefully Mike will chime in here to confirm.

 

[Daniel's Racing]

Lipo is no problem for R603FS/FF and 99% of all current stuff is ok on LiPo.

Better to stick with LiFe for so many reasons.

Get servo's that are strong enough at 6.6 volt and call it done.

 

[Grimracer]

yep.. 2S Lipo is OK to use with all current (including FASST systems) RXs (hard to believe its been 13 or so years since we started using Futaba 2.4 systems!)

Grim

 

[Grimracer]

If you choose to use a Lipo I am sure you know all the care that must be taken with them.. not just charging and discharging but storage is important too.

I like LiFe packs for RX or Nicads...

If you choose to use a Lipo or LiFe and you have older servos (non HV) its BEST to use a regulator. (I failed to follow this a few years ago and it cost me a 3500 dollar helicopter!)

in the end.. higher voltages in standard servos WILL shorten servo life.. (its that when?) that got me...LOL

Enjoy!

Grim

 

[chinslip]

thanks for the help guys, much appreciated. The lipos have different plugs and wont go directly in the Rx. I have ordered a couple of 6.6v li-fe and have 25kg servos rated for 7.4v

 

[Grimracer]

Norm,

There are Lipo setup just for RX use. But.. if you have LiFe please use them then.. just check the info on the battery,.. it should state someplace the C rating. (it should be around 10C for best results)

 

[chinslip]

Norm,

There are Lipo setup just for RX use. But.. if you have LiFe please use them then.. just check the info on the battery,.. it should state someplace the C rating. (it should be around 10C for best results)

it's 20c. Is that okay?

 

[Grimracer]

sure.. I have never seen a 20C Life.. I have seen 15.. O yea.. its good More is better in this case. (sorry I should have said that.. )

NO WRONG.. you got it!

Grim

 

[Samuel Hagan JR]

Does Life and Lipo charge the same?

 

[Mike Starrett]

Does Life and Lipo charge the same?

NO

 

[user 21992]

Been using Fromeco Relion 2600 mAH for years now. Have tried many other and keep coming back to the old dependable Relion, They are compact and as per instructions this are 7.4 Volt Lion batteries (fully charged is 8.4 volt) and they are charged as lipo, (My batteries are from the days of RC Airplanes and do my best to take care of them, some are nearing around 10 years). On 6 .0 volt servos, I do use a regulator that puts out 6.0, and no regulator for High Voltage Servos, be careful here, the receiver must be able to handle 8.0 volts or more, if you don't know play it safe and use a regulator. ---- Fromeco avises to replace Lion batteries every 3 year, ---- So read instructions carefully. Be careful and use, heavy gauge wire connecters. Please read manual carefully if using the 7.4 volt Relion 2600 mAH battery. If regulator is needed, try this Maxx Product product number ACC134N Selectable Voltage Regulator'
Enjoy your Battery Adventure.

Battery:
https://fromeco-scale-avionics-llc..../relion-battery-line/products/relion-2600ma-h
Charging:
https://fromeco-scale-avionics-llc....harger-settings-for-fromeco-lithium-ion-packs
Regulator:
https://www.maxxprod.com/mpi/mpi-21.html#Miracle Switch

 

[dwilfong]

so where do you get a voltage regulator that will let you run the 2c lipo battery's and have a 6V out put to the receiver.

 

[dwilfong]

how about this.
https://www.pololu.com/product/2852or may be this?
https://www.servocity.com/6v-step-up-down-voltage-regulator/

 

[BrianBrownlee]

Amazon also has the regulators

 

[user 21992]

Also would like to mention a little on Radio ON/OFF Switches !! Many are using the push/ pull switch (mostly used for 4.8 Nicads to 6.6 Life batteries) and may not be compatible with the higher voltage Lipo/Lion batteries. With that said, I would highly recommend using a Speed Masters Pull ON/OFF Switch and you will need to solder on your own wires, or, Daniel's Racing carries a nice heavy gage pre-wired Pull ON/OFF Switch with Jr Connecters.

From Maxx Products on regulator, Input Range and selectable Output:
ACC134N Key Features: • Universal Connector • Input Range:4.8V - 8.4V • Selectable Output: 5.95V or 5.4V • Current: 5A continuous, 10A peak @ 7.4V input and 5.95V output, Weight: 0.7oz