Outrage 55o whit A123 8s

[diegoaw]

Hi guys! Have you ever tried the outrage 550 whit 8S A123??

How it would be??

[JustPlaneChris]

IMO that won't be enough for the Outrage 550. It's basically the same size/weight as my Swift, and it performs great on 10S A123. 8S would either give you very (very) short flight times, or mediocre performance (pick one).

[diegoaw]

Do you think that the outrage 550 has enogh room for 10s A123???

How much would it be?? (price) ??

[JustPlaneChris]

Do you think that the outrage 550 has enogh room for 10s A123???

How much would it be?? (price) ??10S A123 will certainly fit if configured in "shotgun" configuration. Since nobody has yet tried to fit A123s in the native "brick" configuration it's unknown if they will fit. Based on reported frame dimensions it will be very close. We won't know for sure until more customers get their 550's and someone tries to fit A123 packs.

Price varies depending on where you get your cells. Used ones from ebay can be around $10 per cell or less, new ones range from $15 to $20 per cell depending on the vendor.

[ktm520]

Chris, how much hs on your swift and what are the flight times with the 10s a123? I'm going to order a 550 any minute now and I would like to explore the option of using A123's.

[sasa]

I tried 10S A123 in shotgun configuration with power tubes. Motor scorpion 4020 910kv and 15T pinion. I tried both governor and fixed enpoints.

I set a head speed around 2000 2100 rpm. And, I am not satisfied with this config. There are big hs drops with loops for example. And the flying time is short , no more than 4 min.

I don't understand yet why i obtain so poor results. Perhaps the motor which is inappropriate ? or my blades ? (i use 550 carbon z- weave blades from hobby city for my tests in case of crashes). Some help would be very appreciated ;-)

I will try 12S I think

Here are some graphs :

http://aquanywhere.free.fr/outrage/A123.jpg

http://aquanywhere.free.fr/outrage/A123a.jpg

http://aquanywhere.free.fr/outrage/A123w.jpg

[ktm520]

That's discouraging.

[LITHIUMSTATIC]

I think the problem is in your motor selection and gearing. Try running a something with a higher kv and drop your pinion down to 12ish.

Or you can always up your voltage which is a better choice. ;)

***Note. I have no experience with A123 packs.

[trextuning]

wow, you got massive voltage drop there dude, are you sure those cells are any good?

[JustPlaneChris]

wow, you got massive voltage drop there dude, are you sure those cells are any good?I've attached a data chart from my 10S A123 Swift, and you can see the voltage doesn't dip anywhere near that much. Now granted, I'm not pulling 2000 watts out of the pack either, but still... wow, your voltage really dips.

If I'm doing the math right, you are pulling peaks of 100 amps, and that's a lot for a 2300 mah cell (that's 40+ C) so perhaps you should take a look at your gearing, headspeed, and pitch settings and try to tame it down a little?

Or perhaps you do have some weak cells there.

[Jamesppp]

If you only want 2000-2100 headspeed, lose the 15t pinion and try a 13, or even a 12t.
Your 100% headspeed at .90eff with the 15t is probably almost 2600 (assuming nearly 30v nom.)so setting it at 2000 will probably put in in an inefficient range.

[sasa]

thanks for your responses.
I tried 14T and wasn't happy with it but I will try again

I don't think that sport flying is possible with 12T or 13T.

How can I check that a cell is bad ?

I thought it was the motor which is inappropriate ? most of guys use scorpion 4025 motor instead of 4020
I wanted to try 12s but finally I 'm not sure if it is the best idea.

[JustPlaneChris]

The 4020 series should be plenty of power for a 550mm helicopter, especially if you are just sport flying. I'm stunned that you are drawing 100 amps just sport flying! :shock:

I think Jimmy is right, you are over-geared. Good A123 cells usually hold 2.8 to 2.9 volts per cell under load, so if you calculate your headspeed based on that voltage you are still in the 2500 rpm range. I'd drop it back a tooth.

The only real way to test cells is under a load, so you'd need some sort of rig capable of putting a load on each cell while you watch its output voltage. It may also be that you have one or more cells that are out of balance, and are simply not charging up to the same voltage as the others in the pack. Have you checked the pack for proper balance?

[trextuning]

100A at 10S (granted it's A123 so not same as a 10S lipo) is crazy. Something is wrong there. With A123 10S that is similar to 9S lipo and 100A would be nuts just sport flying.

[JustPlaneChris]

Maybe I did the math wrong? I was looking at his watts and comparing it to the voltage at the same timestamp on the other chart. :confused:

[sasa]

I tried 14T. It is better but the voltage still drops too low. I suspect strongly the pack even if it is balanced at each charge. that 's weird

thanks for your graph chris, it gives me a good overview of what i should obtain

[ktm520]

I test fit a 10s brick in my frame tonight and it won't balance out with the current setup I have. Shuffling around electronics and with a lighter motor, it could possibly work. Due to the motor I already have for 12s lipo, I'm leaning towards trying a 12s A123 pack. It should only be 140g heavier than the 12s lipo I'm currently running (2x 6s 2500 outrages).
http://www.helifreak.com/showpost.php?p=1219918&postcount=20

[ktm520]

Well, I must have had something in a bind, because I played with some different pack configurations in the frame tonight and the 10s brick will balance out. More details here:
http://www.helifreak.com/showpost.php?p=1224306&postcount=28

I will be testing a 12s A123 pack as soon as I get it built and pick up a 13/14t pinion.