[akb]

Hi Kevin
I am going to try one of the 4600 mah A123 Duralite's for an ECU battery. I know it is weighty but I think the comparable LI-Man is only a ounce or so less. What do you think? It looks like Jetcat is advertising A123's as a option for ECU's. This will go into one of my PST's 1300, though. I guess thinking a little less voltage than LI Ion, LI Poly and LI Man.

Alan

[rcbart]

Thanks guys, I think I will go with the new RX and just use the current battery, ie. just use one. I wanted to use this RX as it has multiple remote RX units and the main unit is buried deep in the plane, with metal 'stuff' fore and aft, this way I can disperse them around the plane for better safety.

It is a shame to ignore the redundant battery choice but really not needed in this small plane. I hope to get it back together and fly this fall of the local grass fields.

ps. Kelly, thanks for the name correction.

Bart

[Wayne22]

Alan, which battery type was giving you the servo jitter at Tofield??

[kev-o]

i ran the 3800 limn pack as well as the 2200 limn pack for ecu and they work great.. to the best of my knowledge all a123 based batteries are lithium nano phosphate not manganese, if an advertiser is stating its limn its not a true a123. i would go with the limn packs they are easier to install (flatter and not so bulky) if you have the room then go with the a123 they are less money,Dean at Norburn has those in stock as well.....

kev-o

[Kelly W]

Hey Guys,

You need to keep in mind that not all turbines are the same... They all do the same thing essentially, but the software algorithms, voltage requirements, current requirements, etc. are all different. Specifically pertaining to the 1300R, I wouldn't count on it reliably running on a 2-cell A123 pack. The starter motor on that turbine is only a Speed 280BB, the same one used in most 54mm size engines... The higher rotating mass and increased torque for a given RPM (aerodynamic drag on the wheels, plug mechanical drag from the bearings) will require a lot more torque... The A123's have an advantage in that they can maintain the voltage at high current draw, but I'm not sure the initial torque from 6.6 Volts will be enough to satisfy the ramp that the ECU expects in the propane ignition phase. Be prepared, since you may wind up purchasing a pack that will not work reliably...

On the other hand, the 3-cell pack will cause another concern... I believe the propane solenoid driver operates by switching a voltage that is pulled off the ECU pack directly. The SMC pneumatic valve that's used here is actually manufactured for a nominal voltage of only 5V! As in, a 7.2 V pack is already working into the design safety margin. I would not recommend going any higher than stock of 7.2. That said, a li-Mn pack is only 7.4 but this is a negligible increase.

Therefor, I would strongly recommend going with LiMn or Li-Po packs on PST ECU's as an alternative to the stock NiCads. Following that, I'd think about Li-Ion but the current draw is not great in comparison...

Kelly

[Ken Currell]

Originally Posted by kev-o

i ran the 3800 limn pack as well as the 2200 limn pack for ecu and they work great.. to the best of my knowledge all a123 based batteries are lithium nano phosphate not manganese, if an advertiser is stating its limn its not a true a123. i would go with the limn packs they are easier to install (flatter and not so bulky) if you have the room then go with the a123 they are less money,Dean at Norburn has those in stock as well.....

kev-o

Sorry guys
I got my chemistry symbols in my previous post wrong.
They have been deleted.
Ken

[akb]

Hi Wayne, I think where I was getting my jitters was because of the 2721's on the rudders, Since I went to 2.4, the rudder jitter went away and caused jitter in the 2721's on the flaps. I went to 8411's on the flaps and the jitter went away. I don't know if the 2721's didn't like the peak voltage off the Lithium Ion's or what. Like I said went to the 8411's and that seemed to solve it. ( by the way I was using a Power Box in the installation and I do believe there is voltage regualtion on the boxes but I don't know what it is)

Alan

[Wayne22]

Just wondering because you were flying the Kc with your 12x...... I forgot about the power box...that would have knocked the voltage down anyways...

[akb]

I hadn't switched the Kingcat over to the 12X it was on the 10x still, at that time.