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Futaba RX's & Servos: NO Lithium Bats, 6v Max??

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Old 12-01-2010, 07:17 AM
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VF84sluggo
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Default Futaba RX's & Servos: NO Lithium Bats, 6v Max??

This morning I emailed Futaba Tech Support about using either unregulated 2s A123 batteries, or 5-cell NiMh batteries, with the s9252 servo. In the reply, I was told that, for Futaba receivers and servos, the voltage must be regulated to no more than 6v regardless of battery type. Further, I was informed that the use of lithium batteries of any type is not recommended and that the risk would be all mine if I use lithium batteries with a Futaba receiver or servo.

This seems to go against posts I've read on RCU where folks are using unregulated A123's and 5-cell NiCd/NiMh with Futaba rx and servos. Heck, I'm pretty sure I've even read where some are running a 2s lipo right into a Futaba R6014HS rx.

NOTE: I edited this post. I removed the exact reply from Futaba Support when I re-read the reply and saw the confidentiality statement after the tech's signature block, prohibiting any copying and posting of his reply, "in part or in whole" on a public forum or emails. My post here is now a summary of what I learned from the tech's reply, and are my words. However, the information presented is an accurate summary of the response.

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Old 12-01-2010, 07:45 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

The new 4 and 6 channel FASST receivers are 8.4v

This is a quote from Bill Baxter on another forum:

http://rc.runryder.com/helicopter/t613644p1/

"Receivers have no problems with 8 Volts. The servos are what have limits."

Bill Baxter, Manager
Futaba Service Center North America
3002 N. Apollo Dr. Suite 1
Champaign IL 61822
USA

Phone: (217) 398-0007
Fax: (217) 398-7721
Email: service@futaba-rc.com
Web: http://www.futaba-rc.com/index.html
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Old 12-01-2010, 08:24 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

Then perhaps I should forward my email response from Futaba Tech Support to Bill Baxter of Futaba Service Center. They should get on the same page.

However, your quote from Mr. Baxter still doesn't address the no-lithium response that I received.
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Old 12-01-2010, 09:37 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

http://www.hobbydirekt.de/product_in...ucts_id=159325

That is the lipo battery for the 8FG, 12FG. Robbe is the European distributor for Futaba.
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Old 12-01-2010, 10:23 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

The issue here in this thread is not lithium use in a Futaba transmitter...it is use with a Futaba receiver and/or servo.

And, more to the point, lithium use wasn't even my intitial question, it was acceptable voltage. The 'no lithium batteries/use at own risk' with Futaba receivers and servos warning in the technicians's response to me was unexpected...and frankly, surprising.
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Old 12-01-2010, 10:39 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

Futaba's official line has always been, "Futaba recommends using 4.8 volt nicad packs, or four 1.5 volt alkaline batteries with their servos and receivers. If you choose to use any battery that is not recommended, you do it at your own risk."

In the US, Hobby Services follows the 'company line' because they probably cannot charge Futaba for warranty work related to damage caused by high voltage.

Just because RCU members write that they use different stuff with no issues, I doubt that Futaba will change their recommendation. If you want warranty coverage you follow Futaba's rules. If your stuff is out of warranty, or you don't care about warranty, you use whatever you want
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Old 12-01-2010, 11:10 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

What I care about is whether or not the A123's or 5-cell NiMh's are going to cause my R6014HS or 9252 servos to fail.
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Old 12-01-2010, 11:57 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

No problem with the receivers, but that servo is for 4.8v only.

I will not use 6.6V or 6.0V with that servo.

Doug.
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Old 12-01-2010, 12:00 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

There is a battery FAQ http://www.futaba-rc.com//faq/faq-battery.html#q782 that mentions regulating voltage to 7.5 going into the receiver
Below it is one about using NiMH or LiPo batteries where the instructions say to use NiCd only.

According to the part notes for your servos http://www.gpdealera.com/cgi-bin/wga...pgm?I=FUTM0222 they are only rated for 4.8 volts and Futaba recommends against using them with 6 volts.

These two things would make me believe the receiver would be pretty safe with the higher voltage and the servos would be at risk.
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Old 12-01-2010, 12:32 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

I've been running A123's unregulated for two years, not one problem. Just make sure the servo is rated for 6 volts. Shoot, I even ran 3003's on A123's.
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Old 12-01-2010, 04:12 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

ORIGINAL: carrellh

There is a battery FAQ http://www.futaba-rc.com//faq/faq-battery.html#q782 that mentions regulating voltage to 7.5 going into the receiver
Below it is one about using NiMH or LiPo batteries where the instructions say to use NiCd only.
I see all of this when viewing that link, but it flies in the face of the "use lithium at your own risk" admonition by the tech support guy. If Futaba "recommends against using lithium batteries", and you "use them at your own risk", why then are LiPo's even mentioned by Futaba in these instructions, i.e. "If you are using...LiPo batteries..." ?
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Old 12-01-2010, 04:30 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

9252s have a 4.8v limit. Why does their response surprise you?
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Old 12-01-2010, 06:11 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

You are spitting into the wind with your Lithium argument.

Futaba recommends 4.8v or 6.0v maximum to retain warranty. Two cell Lithiums are higher than that and Futaba usually states that if you want to use them they must be regulated.

Servos are designed at various voltages for optimum operation. Go beyond that and its service life can end abruptly.

Freshly charged A123's and LiFe packs taper to 6.0v very quickly so can be used providing the servo is also rated for 6.0 volts.

There is no mystery as Futaba's voltage specifications are on the individual products web page.

A lot of radio equipment gets smoked because guys don't pay attention to the specs or think hey know more than the product engineers.
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Old 12-02-2010, 07:15 AM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

ORIGINAL: MikeL

9252s have a 4.8v limit. Why does their response surprise you?
That doesn't surprise me. With the s9252 I was just hoping that maybe 6v would be ok. The part of the response that did surprise me, and still does, is 1) the R6014HS cannot take unregulated 5-cell NiMh (NiCd too?) power, 2) No lithium allowed (not even LiFe?) Why no lithium? What does it matter to a receiver or servo the type of battery that is creating the juice, as long as voltage limits are observed?

BTW, I did get a follow up response from the Tech Support guy when I forwarded him the info in post #2 from DougV in this thread. I was informed that "The new 4 and 6 channel FASST receivers are 8.4v"...no info on what is considered a "newer" 4 or 6 channel receiver. However, the R6014HS is limited to 6v.
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Old 12-02-2010, 03:17 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

Some NiMh cells have very high internal impedence and suffer major voltage drop if they are hit with a big load. It's possible that some lithium cells have the same issue.

Futaba (and their service center at Hobby Services) gives recommendations based on what they KNOW will work, which is 4.8 volt NiCd. If you look at the replies in the Futaba forum when this question was asked in the past (many many times) the reply from Bax or Krysta pretty much says that, and that Futaba has not provided any documentation stating they have even tested any other batteries with their equipment. They officially recommend against using anything else. I guess they put in the "If you are using xyz..." because they know people are doing it and they are saying "We warned you... and if anything goes wrong it is your problem, not ours."
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Old 12-02-2010, 03:45 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

That all makes good sense. Since it's cost and time prohibitve to change out 7 S9252 servos in this Baby Boomer I just got, I'll have to live with 4.8v Nicads. I'd much prefer A123's, but I don't want to add voltage regulators.

And, as you say, Futaba certainly knows what works with their stuff.
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Old 12-02-2010, 07:28 PM
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Dave McDonald
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

If you're waiting for Futaba to officially admit that 9252 servos work fine on unregulated A123 cells, it will never happen.

If you're waiting to hear from someone who has been flying 9252 servos on unregulated 5 cell NiCd/NiMH batteries for many years with zero problems........here I am. About a year ago I converted all of my 9252 equipped planes to unregulated A123 batteries, again with zero problems. If you do some searching, you'll find there are lots of us out there running 9252 servos on 6+ volts.

The speed and power increase on 6+ volts is noticeable. After flying the 9252 servos on 6+ volts for years, I would never go back to running 9252 servos on 4.8 volts.
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Old 12-02-2010, 07:43 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

Thanks Dave. What bothers me about using 4.8v batteries is that when I consider battery lead lengths, servo lead lengths, and voltage demands by multiple digital servos, seems like the voltage actually arriving at the servo itself could be something less than 4.8.
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Old 12-02-2010, 11:08 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

all of Futaba's Rx works with unregulated A123.
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Old 12-13-2010, 01:46 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??


ORIGINAL: carrellh Some NiMh cells have very high internal impedence and suffer major voltage drop if they are hit with a big load. It's possible that some lithium cells have the same issue.
Futaba (and their service center at Hobby Services) gives recommendations based on what they KNOW will work, which is 4.8 volt NiCd. If you look at the replies in the Futaba forum when this question was asked in the past (many many times) the reply from Bax or Krysta pretty much says that, and that Futaba has not provided any documentation stating they have even tested any other batteries with their equipment. They officially recommend against using anything else. I guess they put in the "If you are using xyz..." because they know people are doing it and they are saying "We warned you... and if anything goes wrong it is your problem, not ours."
Futaba FAQ - Can I use 6v (5 cell) receiver packs with my Futaba receiver/servos?
Q. Will I get increased performance from my equipment? Are there any drawbacks to using 6 volts?
A. All Futaba systems are designed to operate on either 4.8 volts (NiCD 4 cells) or 6 volts (Alkaline 4 cells OR NiCD 5 cells), except certain servos which are specifically labeled for use at one voltage or the other only. Some manufacturer's systems are not designed for and do not operate well on 6 volt, but most Futaba equipment handles the increased power input and provides increased performance, speed and torque.
Please note that while 6 volts provides you more torque and speed from your servos, it also provides you a significantly shorter run time for the same milliamp hours of capacity and may shorten the life of your servos proportionally. This sounds confusing, so it may help to compare the current in the battery to water in a bucket. If you have four small holes in the bucket, the water will come out at a certain rate. Add a fifth hole the same size, and you're supplying more water (increasing the current and therefore making the servos stronger AND faster); however, the bucket empties 25% sooner than when it only had four holes."

Standard Futaba (and some other mfg) response on newsgroupsto use of lipo &Life with typical RX& servos
http://www.rcuniverse.com/forum/m_9478498/tm.htm
ORIGINAL: Ace Dude Hi Bill/Krysta, Are Futaba FASST receivers/servos compatible with the new Hobbico LiFeSource LiFe receiver packs without the use of regulators?The Hobbico website says: "With a nominal voltage rating of only 6.6 volts, LiFeSource batteries typically do not require regulators to power the receiver and servos, as LiPo packs do."http://hobbico.com/radioaccys/hcam6415.html
ORIGINAL: Bax -
Futaba has the voltage recommendations for their equipment.
Those are the long-term voltages, so any battery pack that consistently delivers more voltage cannot be used.
Yes, 5-cell NiCd or NiMH packs deliver more voltage initially, but the voltage drops very quickly to 6 V or below and holds there for quite a while.
The LiFe packs hold higher voltages, and so would not be recommended, per Futaba. - Bill Baxter, Manager Hobby Services/Futaba Service/North America
There are some good, e.g.5v or 6v Switchmode Regulator, units available to cater for use of the advantanges of Lipo &LiFe batteries.

Alan T.
Alan's Hobby, Model & RC FAQ Web Links
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Old 12-14-2010, 08:20 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??



Iam faced with a similar issue. I recently repaired an airplane that a club member gave me after he crashed it. Well I did the repairs and found it had 2 9252's in the wings. I know Futaba recommends not to use 6V on these servos, but if I recall I've used them with Alignregulators. My question is, is Futaba recommending against the use of 5 cell 6v Nimh/Nicds which fully charged is 7+ volts? But it can be used with 2s lipo and a regulator @ 5.8~6.0v?

Iknow a fully charged 4 cell nicd/nimh can be 6+ volts when fully charged so 6v shouldn't be an issue Iassume. Ihad a mishap with my spectrum years ago (beforequick connect)due to a low voltage situation while running a 4.8v Nicd, and since then Itold myself Iwill never run 4.8v again, unless it is using 2 batteries for redundency. But the planeI haveis a 60 size skybolt and don't see a need for dual batteries to weigh it down.

If there are many guys running 5 cell nicds/nimhs without issues than IguessI'll jump on the sameboat.

Thanks and Happy Hoiday's from Hawaii

Les

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Old 12-15-2010, 02:10 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

Hello Les..................I'm building a TF Sea Fury and I have two Futaba 9252 in my elevator and rudder. You can use a 6v rx battery as long as It's regulated down to about 5.3v. I will probably use the MPI MAXX Products voltage regulator ACC134N, it has a jumper you can cut to change from 6v. down to 5.4v output regulation. I'm refering to a Nicad RX Battery.
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Old 12-15-2010, 02:29 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??


ORIGINAL: VF84sluggo

What I care about is whether or not the A123's or 5-cell NiMh's are going to cause my R6014HS or 9252 servos to fail.

Well, I can tell you that I am running unregulated LiFePO4 packs (6.6 volts) right now even with servos (S3150) not rated for 6 volts with not one single issue. Beyond that, I have run nothing BUT 5-cell NiMH for the last several years, again with no issues. I have a large number of 9252 servos that I have run on 5-cell NiMH, again no problems.

I have no idea why Futaba is so conservative with their recommendations, but they are. I also know based on my personal experience and that of numerous others that 5-cell NiMH pose no issues at all. I am also establishing a clear track record on the success use of LiFePO4 packs.
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Old 12-15-2010, 03:40 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

My Hangar 9 F4U Corsair has Futaba 9202/9001 2.4ghz RX with an SR Battery 1500 series 6.0v 5 cells Unregulated. Test flight went well.
But my UCD 60 WITH an SR Battery 1500 series 6.0v 5 cell is regulated with an MPI ACC134, 6.0V and HiTech digital servos.

But to play it safe on my H9 Corsair I plan to install the MPI ACC134, 6.0V Voltage regulator.
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Old 12-15-2010, 07:03 PM
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Default RE: Futaba RX's & Servos: NO Lithium Bats, 6v Max??

Hello Les..................I'm building a TF Sea Fury and I have two Futaba 9252 in my elevator and rudder. You can use a 6v rx battery as long as It's regulated down to about 5.3v. I will probably use the MPI MAXX Products voltage regulator ACC134N, it has a jumper you can cut to change from 6v. down to 5.4v output regulation. I'm refering to a Nicad RX Battery.
Ihave an extra Align 6A Bec that chops the voltage to around 5.8v, and if Iadd the step down it will cut it down to 5.1v. Ibelieve that even a fully charged 4 cell nicd/nimh can be around 5.6~5.8v, so Iassume running a regulated 5.8v should be no problem for the 9252's. Ijust have a fear that with a 4.8v pack Irisk the chance of a brownout or other issue regarding low voltage situations.

Imay just get some 6v servos to replace the 9252's and just run a 5 cell nimh.

Happy Holiday's

Les
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