SinCityJets

The use of a CellPro Multi 4 (which actually charges through the balancing connector) will prevent this "creeping" of the high cell, or imbalance issues.

Still to this day, I feel they make the best overall charger.

Chad

JimDrew

My Feedback: (16)

We have been a U.S. distributor for A123 products for over three years. In that time we have had only three packs (two 2300mAh and one 1100mAh) fail. All three failed CLOSED (not open circuit), so the voltage appeared as "low". I do not know if they always fail closed, but these three did. Out of thousands of packs we have sold, I would say this is an incredibly good reliability rate.

A123 packs work with MOST (but not all) servos and receivers. Futaba has issued warnings about using more than 5v with their 2.4GHz receivers. Futaba owners might want to check into this before investing in A123 packs.

A123 packs can be paralleled by plugging them directly into the receiver bus without any type of regulator. All ground (-) and power (+) pins on receivers are tied together. We recommend plugging one into your "battery" port, and another into an empty channel (or through a Y-cable if no empty channels are available). This does two things: adds redudency, and doubles the current capability of your servo bus. Keep in mind that servo pins are only good for about 5A, and the connection really depends on how many insertions/removals you have done. Yes, there is a life cycle on the female connector that plugs into a receiver. So, if you have a jet that uses 14 servos and each draws 1A, you have technically exceeded what the servo bus can supply (before experiencing some amount of voltage drop), even with two A123 packs. The A123 packs themselves will never be an issue for power. Your wiring would burn up long before the A123 packs ever got remotely warm. Considering you can start your car in the dead of winter with the A123 packs (there is a video of that on YouTube), you don't need to worry about the A123 packs being inadequate. I would NEVER use any type of regulator system, and A123 packs allow you to avoid unnecessary hardware that is prone to failure. We don't use switches either. We use a pair of Deans connectors. You plug in the Deans as your "switch". All of our jets (and we have a lot of them, EDF and turbine) all use dual A123 setups.

BaldEagel

News to me, where have you seen this warning?

Nearly all JR servo's are not to be used with over 6volts, but all Hitec and specified Futaba can.

Mike

highhorse

My Feedback: (2)

I only have experience with one such Futaba setup (6014 rx), but there have been NO issues.

BaldEagel

I have used all the current (sic) Futaba 2.4Ghz Rx's with A123 plugged directly into them with no issues, I would like to know where Jim Drew, CEO/President - Xtreme Power Systems has seen this warning.

Mike

Turbotronic

Depending on how much power the RX uses the regulator may contribute some heat to the futaba heat issue (maybe)
Power dissipated = current x ( voltage in - voltage out )
Dunno the futaba current but say 100mA then 0.1 x (7.3 - 3.3) = 0.4watt. For an SMD regulator that is quite a bit. But I dont have the exact nr. Bear in mind linear regulators HAVE to produce heat to regulate. When they overheat they reduce output voltage or shut down to prevent thermal runaway.
One can assume 150 deg C per Watt above ambient worst case. So that would mean 60 deg above ambient.
This kind of physics probably does not apply to jets unless its printed in a purple font.

BaldEagel

Turbotronic

Thank you for the explanation, but I would like to know where Jim Drew, CEO/President - Xtreme Power Systems has seen a warning from Futaba concerning using over 5 volts, as Futaba make servo's designed for use with 6 volts I can't see them issuing a warning not to use over 5 volts ?

Mike

phjoker

My Feedback: (4)

I would like know where to see the warning also. I have dual A123 set ups in both my jets with Futuba Receivers and Futuba Servos and have had had no problems at alll.
Now if Futaba had issued warnings and you know about them since you are CEO/President of Xtreme Power Systems you may have heard more then the public so you should have no trouble in pointing us Futuba users in the right direction in seeing these warnings. Correct

Ivo60

hey guys I would like to try to run a life a123 pack in my Sig Mayhem 3-d airplane.... I am using a spectrum 7 ch. reciever (no prob. im sure) but I am using all futaba s3305 analog, Hi torque, Metal gear servos and NOWHERE can I find if they can handle the voltage without a regulator????? I have4 been using a 2000mah 2-cell lipo w/regulator and no problem. Id like to switch to the a-123 w/o the regulator as I understand if you eliminarte the regulator its less to go wrong??? But im afraid to do it??? Any help would be appreciated!!!! Thanks in advance!!! Stef, Rockford Il.

Turbotronic

These guys had this question as well seems Futaba puts the limit at 6V as you say. The current draw is apparently 40mA.

http://avcom.co.za/phpBB3/viewtopic....50093&start=15

BaldEagel

A 6volt Nimh (5 cell) comes off the charger at about 7.2volts so A123's will be no problem in my estimation.

Mike

DougV

We’ve been using A123’s and 2cell LiPos straight to FASST receivers for over 3 years now with no problems at all, the problem is not the FASST receivers, the problem is some of the Futaba servos that don’t like voltages above 5.6 volts.

Doug.

gooseF22

Agree here too for balancing charger... +1

gooseF22

I tried to give some information before that should help people if they think they overcharged. These are the best value out there for powering a plane, but they are not foolproof charge and go types. It takes some new habits. You cannot trust voltage checks or load checks because the battery is a flat discharge. It drops off like a rock at about 2000Mah, but until then it will provide flat power unmatched. so you need to know what your model uses per flight.

Like I said before, the failures I have had have either been intentional, or attributed to human failure on my part or a crappy offbrand charger I was testing that ruined the pack by reverting to Lipo charge and popped the cell.. I havent had a pack just fail..

Fromeco has given me a wonderful opportunity to test things, so I get to find out what happens if.......

BaldEagel

Jim Drew

Still waiting for the link?????

Mike

JimDrew

My Feedback: (16)

http://www.rcgroups.com/forums/showt...a#post15152541

Contact Bill Baxtor, head of Futaba service for Hobbico.

Interestingly enough, the voltage regulator used in the 6014s we have here will handle 16v, which is why our specifications chart shows this as Futaba's max input voltage being 16v.

BaldEagel

Jim Drew, CEO/President - Xtreme Power Systems

So not first hand knowledge from Futaba, but someone else's post that you have assumed is correct, not very convincing.

A123's directly into any Futaba Rx's works fine so do any of the Futaba servo's that are listed as capable of being used on 6volts, now to make this clear, 6volts means 5 cell Nimh and as they come off the charger at 7.2volts the statement that Futaba have said that their equipment can not be used with over 5volts is clearly a nonsence.

MIke

P.S. Jim if you allways belive posts then: I am the new Mesiah, please send me all your ill gotton gains and I will give you redemption.

JimDrew

My Feedback: (16)

I talked with Bill about it the issue, because we are a distributor of A123 products in the U.S. I posted the link because others also got the same answer. Call Futaba service yourself if you want to hear it with your own ears.

BaldEagel

What I will do is ask Futaba direct its easier than phoning the US from the UK.

Mike

Turbotronic

Jim,
Can you tell us the current use of the 6014 RX that you based 16V on because I know you did the power disipation calculation to calculate the temp rise on the die (as it is mounted on the PCB) versus the current/voltage limiting feature of the regulator. Being a power systems expert and developer of the famed XTREMELINK this information could be very usefull to puts folks mind at ease. I for one think A123 is the best/safest solution to R/C power supply issues. I know I will not use LIPOS ever again. I had a close call with a Lipo fire.

JimDrew

My Feedback: (16)

I looked up the part number of the LDO regulator they use in the 6014, and it has a maximum input voltage rating of 16v. No calculations required.

Turbotronic

Thanks Jim, That explains it for me.
I suspected those chip engineers did not know what they were talking about. Early Futaba RX's has a 70ma draw ( reduced to 40mA apparently) so according to their uninformed ( unnecessary) calculations the power dissipation (heat) generated by Watt = (16 -3.3) x 0.07 = 0.889 Watts.
They also claim that with a regular PCB as heatsink the junction temperature will rise 175 deg C per Watt dissipated. So 175 x 0.889 = 155 deg C above the existing RX temperature. I mean really, that would boil water! Then they claim it will shut down at 125 deg C. I mean really what are these guys thinking.
I had the same problem with my Volvo. The claim 30 mpg and 150mph top speed. I never get 30mpg at 150 mph. Those fools...
I will take it up with them, just you wait..
Andre

Jgwright

Jim

I have spoken this morning to Technical at Ripmax (UK Futaba reps) and they say their products have always been able to use a 5 cell NiCad pack without a regulator. They state a nominal 6v in the specs but they can cope with a freshly charged battery which has significantly more voltage. Of course A123 batteries with a lower voltage are fine without a regulator. The more recently supplied receivers (last 12 months) are able to be run with a LiPo without a regulator. They are not aware of any statement about a 5v restriction.

My own experience with Futaba 35Meg and 2.4 receivers is that they work perfectly well with a directly connected 5 cell battery and no regulator. All my planes were connected that way until A123 batteries came out about 2-3 years ago. I switched over to A123 batteries and have some with direct connection and some with dual packs to a powerbox sensor switch regulated to 5.9v. I have never had a problem. A123 batteries have proved a huge improvement over NiCad or Lipos for receivers. The very fast charging times make charging up twin battery packs so much quicker and there is no danger of catching fire. I have used RF6014 and RF 617 receivers both with and without regulators.

I can only think you have got confused.

John

BaldEagel

Well I don't know if Bill is anyone to take any notice of, but the US Futaba support site says you can use 5 cell Nimh, perhaps you ought to talk to Bill and understand what he is saying: http://www.futaba-rc.com/faq/product-faq.html#q26

Mike

DougV

Here's more info:
http://www.rcuniverse.com/forum/m_8804658/tm.htm
http://www.rcuniverse.com/forum/m_96...tm.htm#9678469

Again worry about the servos, not the receivers.

Doug.