Just switched to A123

[zeta30]

I have just switched to the A123 2300mAh 3s pack on my CopterX 450.

Unfortunately I haven't had a great chance to try them out because I have been rebuilding the Heli after a crash.

So this is my set up power wise.

A123 as stated above
Scorpion HK2221-6 motor
Scorpion Commander 55A ESC
Logictech 2100T Gyro

As soon as I get the vibration fixed I'll be able to give it a go. I have been doing some hovering whilst attempting to fix the vibration and the fast charge times are very nice. My charger is only an 80amp charger and can only charge up to 8C but it still gets the job done in 20 minutes.

[dude_109]

What pinion size are you using and what KV is that motor?

Considering the lower voltage of 3s, I guess you'd need either higher KV or higher pinion to get that headspeed back.

[zeta30]

The motor is 4600KV 52 max amps.

13T pinion.

I still haven't been able to give it a good test because am having a heck of a time tracking down a vibration problem.

[Bunyan]

Hey,

I've tried a 3SA123 in my 450 as well with moderate results. It will do light acrobatics for about 5 minutes and then dumps pretty fast. I've had better results with 4SA123 but then you're fighting with the weight of the heli.

You also have to make sure you turn your lipo saver off on your ESC so it won't cut out on you when the voltage drops under load.

Makes a good pack for just practicing though.
I've got a Strecker motor (German made) 2300 K/V with an 18T pinion. Gets me about 3K on the head.

[zeta30]

Thanks for the info Bunyan.

I was able to get in 2 packs at the field down the street from me. (I finally got the vibration problem resolved). I was able to get 6 minutes of very easy sport flying and hovering. I think the A123's are perfect for my abilities. I'm still very new so I can't do any loops, and can barely get some long, messy figure 8's.

I will be making a ZIP line soon so I can charge at the field. Right now they will charge in about 20 minutes on my TP610C charger.

[Appleflyer]

cool! i would like to see how it terns out!

[zeta30]

I got my ZIP line made, I can now charge my packs in about 10 minutes. I'm getting about 10A charge rate with about a 14' lamp cord. The cord gets warm but not really hot.

I put deans connectors on one end and plug that in to my Whatt Meter. Then that to my batts. The other end to the power source. Once the Volts get up to around 10.8 the Amps will start dropping and the volts will rise pretty quickly. I unplug the wires when it gets to around 11.5V.

[dude_109]

Can you show a picture of the mounting of that A123 pack? I'm having nose-heavy problem (not that bad actually) with a 2150mah lipo so I'm afraid A123 would just make it worse. Did you remove the battery tray and just stand the A123 vertical as far back as possible?

[zeta30]

Here you go. I basically unscrewed the rear two screws on the battery tray and pivoted it down, then I put the A123 battery on the lower tray, using the Velcro on the upper tray.

I have no balance issues at all, but I also don't do 3D, I can barely do figure 8's at the moment. I really like the A123's because it only takes about 10 minutes or less to charge the pack.

[Turbojoe]

I've got a bunch of A123 cells. I just started using them in my planes with mixed results. A 4S 123 pack doesn't have the performance of a 3S Li-Po in a hot plane but they charge quickly and last forever so I use them in my larger trainer types now. I considered trying them in the heli and now after reading this thread I'll definitely build a 3S pack and give it a try. I'm just getting back into flying the T-Rex again and high power is the last thing I need right now. I basically have to learn what little I new all over again.

Joe

[zeta30]

One thing you will want to consider is that since the voltage is so much lower on the A123 packs you want a high KV motor. I have a Scorpion HK 2221-6 4400KV motor with a 13T pinion.