jetmech05

Ok quick questions I understand Futaba does not recommend using lipos in a transmitter.
i know folks are doing it, what would the fully charged voltage be on a lipo transmitter battery. At what point would you recharge.
Thanx

JohnShe

Neither a 2 cell or a 3 cell LiPo has a suitable voltage. Plus, I doubt that you can find one that fits. If you want to go to a higher capacity, you can go with a 9.9v LiFe. That will definitely work. HobbiCo makes one that you can buy at Tower Hobbies. I have been using one with great success.

Try: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAEBY

jetmech05

At what voltage do you recharge

Hossfly

I am very glad that there are folks a lot smarter than me plus being braver. I see too many of these guys starting fires with Lipos and they don't even have any weiners to roast. For transmitters there are so many good batteries available, such as 2600 mah Nmih, and Lithium Ion which lasts a long time and IMO as stable as Nicads and Nmih.
Scary!

Rob2160

When I first got into 2.4 Ghz radios one of my first was a Futaba 6EX, I bought a 3S lipo for it but did a bit more research after buying the lipo (yep, too late then) and decided the risk wasn't worth it so I never used it.

A 3S LiPo fully charged will give you around 12.6 volts.. Probably a little high for a TX designed around 8 NiCd / NiMh cells ( max I get from those is about 11.6volts)

I would recharge it when the voltage drops to 11.1 Volts. (3.7 volts per cell)

flyinwalenda

My Feedback: (5)

I've been using lipos in my Futaba radios for 5 years. The voltage on the display coming off the charger is 12.2 but drops off fairly quickly from a full charge and holds steady around 11.9/11.8 . I recharge when the display reads 11.4. I'm recharging more often now that the packs are several years old but they hold a charge for a long time. If you are worried about the high voltage you can add a diode or two to drop the voltage, or use a LiFe pack.

TimBle

which futaba transmitter is the subject of discussion?

scale only 4 me

My Feedback: (158)

Been running the same 3s lipo in my 8uap and my 10cag for 3 years with no ill results,,, I'm sure Futaba doesn't recommend using anything they currently don't sell. Once they start selling one, the recommendation will miraculously change

scale only 4 me

My Feedback: (158)

Sir, sorry you're wrong, Lipos for TXs have been available for years, One example http://www.valuehobby.com/power-syst...ry_connector=3

eddieC

My Feedback: (2)

LiFe cells are 3.6V/cell when full, can be run down to 2.5V/cell but 3.0 is a good point at which to recharge. Using a 3-cell, that coincides with the lo-batt alert on many tx's.

JohnShe

Well scale: That is more of a yes and no situation. Most of the Futaba Tx line (excepting for the very newest and most expensive) use NiCds at 9.9 volts. Since the initiator of this thread was asking about Futaba txs that "did not" use LiPos then my answer is valid.

The LiPos you found at value hobby could damage your Futaba Tx as the voltage is much higher than design.

757jonp

My Feedback: (48)

I've been using a 3 cell lipo in my trusty old 9C for about 2 years now without issues of any kind. I don't have to charge it very often, but when I do, I remove it Best thing since sliced bread IMHO.

Yours may vary.....

Hinckley Bill

My Feedback: (569)

Futaba' latest, greatest TX, the 18 MZ, uses 2S LiPo's

http://www3.towerhobbies.com/cgi-bin...&I=LXBYFG&P=WR

JohnShe

Well 757 I wish you the best of luck. As expensive as those suckers are, I don't like to take needless risks. So I'm gonna stick with 9.9v.

JohnShe

Bill, You are correct, but my 7C takes 9.9v NiCd or LiFe. And the original question did not appear to address the 18MZ.

VF84sluggo

My Feedback: (55)

Been using a 2s LiPo in my 12FG for almost 3 years, no trouble at all. Works great.

eddieC

My Feedback: (2)

Jet mech,
A fresh 8-cell nicad pack just off charge can approach 12.0V (1.5V/cell), and a fully charged 3S Lipo is 12.6V (4.2V/cell). Their nominal ratings are 9.6V and 11.1V respectively.

byrne1157

My first Tx was a Futaba 6 EXA. Bought a lipo tx pack for it the 2nd week, used it for 2 years. Always charged it to 12.55 volts, never once had a problem with it. My 2nd radio is a Turnigy t9x, bought a lipo pack for it when I bought the tx. Still using it, with no problems after 2 years. Charges to 12.6 volts. I always charge when my lipos get to 9.9 volts. (3.3v per cell.) The battery in the Futaba is a 2200mah 5c 3cell, the one in the Turnigy is a 2600mah 5c 3cell. I charge about once every 2-1/2 months. And I do fly quite a bit, and use the tx's for setting up airplanes. Not saying anything bad about theirs, but very happy with mine!!

TimBle

Since the OP hasstill not answered the question on which Tx he is refering too, the 8FG, 14Sg and18MZ can all accomodate 2 Lipo, 2Cell Life or the supplied NiMH packs

scale only 4 me

My Feedback: (158)

You statement that you can't find a lipo to fit a futaba TX was dead wrong,, use what you're confotable with, I'm not trying to talk you into anything.

A full charged Nimh pack comes off peak at near 12 volts, measure the voltage coming off your wall charger,, beleive me it much more than the 9.6volt rated pack,, the TXs can take it just fine,, us guys who have been using them for years have proved that.

good lck

Hinckley Bill

My Feedback: (569)

John, the original statement was, "Ok quick questions I understand Futaba does not recommend using lipos in a transmitter."

Up until I bought my 18 MZ Futaba transmitters I owned either had Ni-Cd or Li Ion batteries....was actually kind of surprised they went with LiPo's. Something in their 'logic' of suitable batteries must have changed eh?

Bill

757jonp

My Feedback: (48)

It's been my observation over the years that just because Futaba doesn't recommend it doesn't mean it won't work.

chris923

My Feedback: (53)

I have been using 11.1 2500mah lipos in my 7c-9c and 10c radios for 5 years! I always charge them OUT of the radio. I always recharge them when they reach 11.1 volts. Many of my fellow clubs also use lipos in their Futaba Radios (more than 50 users). Not a single radio failure, no battery fires inside radios, NO having to recharge every day.

They work!

If you don't want to use them don 't, it's your choice.

futura127

My Feedback: (57)

I have been using Value Hobbies 3S in my 10C for over 3 years without any issues at all. I fly until mine hits 11-11.1V and then recharge. Good for another 2-3 months of flying for me. My buddy and many others at our field also use them without any signs of problems. Now having said that a good friend of mine that I have known for 34 years decided to buy one for his Futaba 6EX and he used it a few times without any issues but then all of a sudden he had 3 airplanes go into lockout and they flew away, all within or < 5 minutes of taking to the air. These were all different receivers/equipment and planes. Lucky he had one he found that went into a corn field with no damage. This was 2.4 by the way. I was told by another friend that has flown Futaba forever that the 6EX radios do not like the high voltages that are maintained by using the 3S lipos. I know people using them in 7C,8series,9C,10C,12 and 14's though with no issues.

Mine usually charges up to 12.2V but as someone else above stated it drops quickly down to 11.7-11.8 and usual stays there for a long time.

Oh I also charge mine out of the radio and keep a fully charged one in my transmitter box ready to go just in case I do hit that 11v mark while at the field.

G.Barber

My Feedback: (1)

I , too, went to a LiPo battery in my Futaba 7C. I am using a 11.1V 2800 mAh pack that was designed to fit in place of the original NiCd battery. I have been using it since April, and the only difference I have noticed is how often I have to recharge the battery!

I definitely love not charging every time I want to go flying.

I actually contacted Futaba, and they said that they could not recommend using a LiPo battery, but it hasn't had any ill-effect on my transmitter.

With that said, I can only imagine that individual results may vary, and only comment on my one experience.