mavrick

My Feedback: (1)

HI Guys Is anyone running A123's straight into there receiver's, So far I have been using a Turbo Reg set at 5.9 into my AR9100's but can't see much point as a fully charged 5cell
is over 7 Volts if you can run the batteries straight into the receiver it is something less to go wrong. All my servo's are Hitec 645's and 5645's just like to get your view's.
Mav

cavandish

I have the powersafe rx and feed it with x4 two cell life batterys, divided into 2 parallel packs my servos are 5645s.
This is an awsone set up giving nearly 9 amp hours of power, I charge at 5 amps in the plane , swapping 1 charger around, this takes very little time after a day at the field. The other great thing is that these 2200 mah packs are $11 each.

phjoker

My Feedback: (4)

I have 2 A123's going into an Orbit Power Jack on my flash and 2 A123's going into my receiver on my Boomerang. No problems what so ever..

erazz

FWIW it's usually the servos that suffer from overvoltage.
I've been running 2 A123's into my Rx without a problem for more than a year now.

highhorse

My Feedback: (2)

Lots of folks are running unregulated 123's without a hitch.

Helijet

You are fine. I have an A123 pack no reg. in my Spit running all Hitec servos - no issues. In my Panther I run two A123 packs into the JR 9 channel dual battery. Again no regulator with a mix of JR and Hitec servos. One thing I have discovered though and this has happened three times to me. The JR 2721 analog servos with extension leads longer than 18 inches DO NOT LIKE THE HIGHER VOLTAGE. Considerable jittering around neutral occurs to the point where I have removed them from flap and rudder applications. Guys may use them but I believe this to be a high potential failure point.

d.w.

tp777fo

My Feedback: (28)

That's how I do it 4 jets, no problems.

sidgates

My Feedback: (2)

Most of the 2.4GIG receivers were designed for a larger voltage range but I would check on the receiver you are using. Servos are another matter. As Dean pointed out the analog servos he has are jittering. I would be very cautious about the servos I use on higher voltage. If not rated for high voltage they may work at first but are easier to over stress under high mechanical loads and may burn out. Check the manufactures specs first in both case.

quist

My Feedback: (198)

I am running a batshare inbetween the battery and receiver. The diode in the batshare drops the output voltage by .45 volts. It also gives you battery isolation.

SinCityJets

Mav,

A fully charged 5 cell nimh pack peaks out a little over 7 volts also. We have sold over 3000 packs of 2 cell A123's, and I haven't ever heard of a problem with someone running them direct to the receiver. And, truth be told, it's not the (modern) receiver that would have the problem, it's the servos. Most any (modern, NON 4.8v specific) servo is going to handle the voltage just fine.

Chad

Countryboy

My Feedback: (25)

Like others have quoted, it's not the receiver you need to be concerned with. The AR9100 can handle up to 10V and has built in battery isolation.

BaldEagel

The A123's straight off the charger are 3.6 volts per cell that means a two cell is 7.2 volts, a five cell Nimh is well over 7.2 volts can sometimes come off the charger as high as 8.6volts, so be more worried about running Nimh's than the A123's straight into a Rx, been running A123's two off straight into a Futaba 6014 for about two years with a single problem.

Mike

David Jackson

My Feedback: (15)

This post could not have come at a better time. In the past two days I have managed to smoke 5 Hitec digital servos, (1)5955 and (4)5645s. In one day, four servos smoked in my 1/4 scale Corsair and one was lost in my F-4. In each case, dual A123 Racing 4800mah paks were used and attached to a Smartfly EQ10. Luckily, both planes were on the ground. [8D]

SinCityJets

A Smart-Fly EQ-10 introduces an additional .5 volt drop. It's not the A123's causing your problem, it is something else in your set-up. I have used over a dozen 5955's and 5645's in my GS stuff direct from A123's. Check your set-up, I'll bet they are fighting each other.

Did you set up your aileron (and other multiple servo surfaces) using an amp meter? PM me if you don't know what I am referring to.

I hope you track it down.

Chad

David Jackson

My Feedback: (15)

Chad,

One servo operated the retract valve, three servos on individual flap panels, and one on an aileron (no multiple servos used on any one surface). In each application, the surface or valve being controlled moved freely without any binding. Servos actually failed as soon as the system was powered up or within seconds of system being turned on. The puzzling part about the whole situation is that I have used Hitec digital servos for more than 10 years on all my jets and large prop planes without any problem. On my 40% Yak, I have three servos per aileron panel and two per elevator and have flown this plane for the past 2 years (Hitec 5955s) without issue. However, it is an EQ 10 system powered by LiIon batteries on a Turbo Reg. So until I discover the real problem, I will play it safe and use a regulator with the A123 batteries.[8D]

By the way, I always charge my batteries the night before I fly. Again, just glad the plane was on the ground when the servos failed. Hitec should soon receive a package for me with the first four dead servos.[8D]

SinCityJets

Ouch David. Sounds like you just got a bad batch. Even if you wait for 30 minutes after the batteries have been charged, they will be down to about 6.8, and the EQ10 puts another .5 volt drop in there.

I hope you get it sorted out!!

Chad

cavandish

it is also somthing else to go wrong.

SinCityJets

The system is completely redundant. I use an EQ-10 (has built-in bat share) on any plane I have thats worth anything.

Chad

Vinceyboy

Hi Guy's are these A123 batteries okay to use through a Powerbox Evo? as i am a bit dubious about using Nihms on my jets due to the hype I have heard about their sudden voltage drops.

Cheers,

Vince.

Turbotronic

David, I had the same happen to me years ago with JR8711 is. I still have 20 dead servos to prove it. The problem is not the A123 or the Batshare gizmo directly. The problem is with the servo amplifier design, specifically the motor drive circuit which consists of 4 mosfets. When I had 20 servos let go in a $m's UAV I had to look into in because of certification requirements. I was surprised to see the amplifier had none of the inductry standard measures designed in to prevent the mosfets from failing under power surge conditions. So we had to add spike protection on the power bus to the servos. BTW this spike also caused other analog servos to let go. None of these servos even moved from their neutral position at power up. The better the batteries ability to deliver power the worse it gets. Also by putting diodes in series with a batshare gizmo also makes it worse since the battery is no isolated from current flowing back into it so the spike in not absorbed by the battery. In fact that setup resembles a voltage step up converter when you add high current pulses to it!
I repeat its NOT the battery or qizmos problem. I am sure if the gizmo manufacturer were aware of the problem and understood it they would add the spike protection to their device. But the spike protection needs to be in the SERVO itself.
How can this be fixed. All you need to do is add a 12V TVS diode of the bidirectional type across the bat + and Batt- as close as possible to the servos and other sensitive electronics.
It is important to understand the servos did not fail because of too much current draw but an overvoltage (30V - 100V+) condition. This makes the mossfetss all conduct at the same time and voila... SMOKE.
I designed my own FASST gizmo for this purpose for use with high $ models.
Here is a link to what you need. It will kill 1500 Watts of spikes! They do come in smaller packages but this one looks the part as well.
http://search.digikey.com/scripts/dk...5KE12CADICT-ND


Andre Baird

BaldEagel

As far as I know A123's do not come in a muliple that will allow 4800Mah to be achived, are you sure of your cappacity and they are genuine A123's?

Mike

Turbotronic

For the teach minded here is a doc explaining the same thing it automobiles.


http://www.vishay.com/docs/88490/tvs.pdf

http://www.vishay.com/docs/88436/appnote.pdf

All of the details are contained in this design, including a whole lot more...

mavrick

My Feedback: (1)

Thanks guys for all the input I have three jets now 2 running A123's and one with 2X 4500 Mh 6.6 V Lifepo4's all going through a Turbo Reg with out any problems but I thought I would just run it past you guys to see if any one was going straight into the receiver ,I use all Hitec servo's 645 &5645.
Thanks again for all the input
BRG Mav

TimBle

I run my LiFePo4 straight into the Futaba R617FS RX and using Towerpro SG5010, MG94, Futaba S3152 and S3004 servos in my planes. No prblem but Futaba Rx are far less voltage senstive than JR. They work happily with the Hyperion LiFePO4 I am using.

mavrick

My Feedback: (1)

All my receiver's are AR 9100 Spektrum with 4 remotes
Regards
Mav