Are the A123 packs a viable option for 3D or not?

[jlewis99]

your first pic shows a 45HV, is that enough to handle the 10S A123 pack and the stock 600L motor?

[Cryofix]

I use a HV45 on a Zpower Z30-800 with 10S on my logo 10 no problems there, swingin 550 MM

[ozace]

your first pic shows a 45HV, is that enough to handle the 10S A123 pack and the stock 600L motor?

Very observant :shock:

That first pic was a mock up of the A123 cells. At that time the heli actuall was running a 1515 Neu and the HV 45 with 10s emoli cells. The emolis can only deliver 45 or so amps so it was no issue. When i swapped to A123 cells it was working fine but i swapped to a different motor 1512 neu so i swapped to a mgm esc i had laying around which can cope with more amps than the 45 CC.

My 600l motor only did 2 or 3 flight in the 600 as it killed my Align supplied pack (combo kit) and thats when i swapped to more affordable and robust packs.

[MrMel]

Good bye Mr Lipo!

After more or less killing TWO 10s lipo last weekend, Ive been hunting the optimal A123 setup for my T600.

Today I can only say YES!

15s1p A123 will replace my 10s lipos, even for 3D.

Key is however setup, a bad setup on A123 and its performing REALLY bad, not even sure ive found the optimal yet, but I got better performance/same then my FP 10s packs.

Here is my setup.

T-Rex 600 using RotorWorkz HFE frame.
Neu 1912/1Y with 13T
CC 85HV controller
AeroSpire e-Governor
1 x 5s1p A123 stick config
1 x 10s1p A123 shotgun (using solderless kit from MEC)

Just tested some punchout's and rainbows in the backyard (actually the rainbow was even on the neighbors backyard hehe, he's at work.)
And the power is there!

I got it pretty good yesterday, but today when the E-Governor arrived, it was the total success, A123 flux so much in voltage, so you need a good governor, must say it exceeded all my expectations.

Overall weight was 250 grams higher then my old 10s1p 3700 setup.

OBS: This was in -5C with windchill making it -14C (23F/6F), Lipos would have died in a hardbeat :)

Flighttime as you can see: 4 minutes 15 seconds until voltage sags, I suspect it will raise a bit when temp is higher, A123 at such low temp is only running at 85-90% capacity.
http://www.dacsa.net/heli/t600/a123/a600-YES.jpg

[kenkamm]

Awesome. However I'm not ready to jump to that many cells. I'm going to try the 10s A123 brick. I don't need to be able to do hard 3D because I can't do it yet. But I'm hoping for "good" performance. I have a Neu 1512 on the way and just got my CC HV-85. Now if I can just decide which firmware to use in this thing... :lol:

What's your flight weight?

[MrMel]

v1.55 works fine.

AUW 3770 grams with all cables, loggers etc.

[kgfly]

Fascinating data Mr Mel, thanks for sharing your experience. That is amazing performance for an A123 pack: 80A and almost 2.8kW :shock:

That end voltage of 26.6 is only 1.77V/cell :shock: Isn't that dangerously low and well below the recommended minimum of 2.0V ?

How did the recharge go ? How was the balance ? It would be great to hear more as you go along about how the cells hold up after 10, 30, 50, 100 cycles (and 1000 if you get there :lol: )

[MrMel]

I dont balance the cells since the TP1010C cant keep up when charging (voltage flux too fast) but they are perfect in balance when you let them rest a few minutes.

A123 Cutoff:

Recommended at 25 degrees C: 2.0v
Recommended at 0 degrees C:0.5v

Ive talked to several that has run them into the ground at normal temps too, without anything happened to them, just let them rest a few minutes and they will normalize back to 2.6 volt per cell.

I think Charles (everydayflyer) at rcgroups has something like 150 cycles on his pack, running it until his truck stops everytime, still working as new.


Sidenote: Fedex just arrived with a Actro 24-3 (740kv) gonna try that next :)

Edit: Pack took back 2250, so they was empty.

[kgfly]

FP3700 10S = 960g, USD$465 :shock:
A123 15S = ~1100g, ~USD$165 :thumbup:

Is that about right Mr Mel ? If so that means you could have 5 A123 packs for the price of 2 lipo packs PLUS if you can find a suitable charging solution, charge them at up to 10A.

Do you charge these as 3 x 5S ? What ps/charger/balancer setup ?

[MrMel]

Had to try the Actro in the backyard before darkness.

Same extreme power, however, the Actro is running ice cold (all actro's does)

Same pack, disregard the voltage of the pack though (either this or the other is wrong), Im trying out different calibration methods.

(I have to connect the EagleTree to one of the pack in series, else it will burn)

http://www.dacsa.net/heli/t600/a123/t600-a123-actro.jpg

[MrMel]

FP3700 10S = 960g, USD$465
A123 15S = ~1100g, ~USD$165

Is that about right Mr Mel ? If so that means you could have 5 A123 packs for the price of 2 lipo packs PLUS if you can find a suitable charging solution, charge them at up to 10A.

Do you charge these as 3 x 5S ? What ps/charger/balancer setup ?


Its more like 1200 grams for the 15s pack, bare cell weight is 1050, but you need to run a long wire on that 5s pack, plus the series cable etc.

Cost is a bit higher for me, since I have to ship to sweden, but for US thats how cheap you can get them.
Total cost for me was about 16.50 per cell + $16 for the spt-kit.
Total cost for a 15s1p: $263

Still, I have high hopes for cycles on this setup, time will tell.

Im using the config one 5s stick, and one 10s stick, the 10s is built by using this:
http://www.modelelectronicscorp.com/products/SPTs/kits.php

The 5s you can either:
just use silver paste (bought at mec), and tape/shrinkwrap,
or you can end-to-end solder them
or you can use Dewalt pack, keep the tabs and just fold them togher.

I done all 3, all works. with the Dewalt pack I "tripplefold" the tabs, so they dont go outside the size of the cell.

Charging: I have 2 x TP1010C which I use if Im not in a hurry :)

I also have this monster:
http://www.tanicpacks.com/catalog/product_info.php?cPath=90&products_id=712
Charging a 10s pack in less then 10 minutes(!)

[Cryofix]

MrMel!! Whoot just what I want to hear, I ordered my HFE frame from Charley on Monday, should be in today or tomorrow, waiting on a deal now for a CC 85 controller, hopefully that will go through, I may be getting a Z50-800 with the controller also if not I am interested to see how this pans out with the Actro

Where did you pick up the Aerospire? I was actually thinking that using different curves on throttle for a 2 position flight mode would allow for much better power through an entire flight, especially if you geared high, but the governor sounds like a great idea especially if its working that good. Now is we could just get Castle Creations to release an update for A123 cells, maybe there built in governor would be a bit better.

I plan on going 14s as I already have my packs made for my Logo 10 (10S A123) and my 450 se runs (4s A123)

[MrMel]

I ordered mine online at www.aerospire.com.

I can try a Z50A-800 tomorrow if you want a comparison data :)

However, With the Z50's, you need to adjust/trim the canopy, they are higher then the Actro and the Neu, and touching the canopy when you doing negative pitch.

[Cryofix]

Would love to see the comparison only becasue the cost of a Z50A is about half the cost of an actro or NEU

[ozace]

:smokin: :smokin: :noteworthy

[kgfly]

the 10s is built by using this: http://www.modelelectronicscorp.com/products/SPTs/kits.php
Well that is interesting too. I see two potential disadvantages, no balance taps and poor cooling.

* Do you plan to disassemble the packs every so often to balance the cells ?

* How would the SPT hold up mechanically if you drilled some cooling holes along the length of the shotgun tube ?

I look forward to hearing of the progress of your packs and the temperature profile when the ambient termperature gets over 25C.

[ozace]

KG, the powertubes for these sized cells do not use the shotgun tube, they use heat shrink and are a pain to disassemble. Taps can be added during assmbly if wanted. I have some in powertubes as well bu tlately i have just been folding the welded tabs to the shape needed and heatshrinking the sticks, its easier to do and
no risk of cells loosing contact.

[jlewis99]

ozace,

when you get a chance, I'd like to see one of these packs where you folded the tab.
I have some A123 packs that I have not disassembled and I'd like to find out what others are doing being I sperate the cells. If I can leave them attached, that's even better!

Thanks!

[ozace]

i hope this helps

[kgfly]

So no balance taps on your A123 packs ozace ?

[ozace]

Nope, not worth the effort from my point of view. I have had to manually balance one 10s brick (my first from september 06). The rest (5 other sets) are all still balanced. Keep in mind i dont fly until they are flat nor do i charge at more than 1c. My reason for these cells is low cost (average $100 US per 10s brick) and saftey, i cant burn down my house or car with these things and they tend not to get damaged in a crash.

[MrMel]

Do you plan to disassemble the packs every so often to balance the cells ?


You really dont need to balance the packs, even if you by accident overcharge one cell to 4.2 volts, you dont kill it, if you do it for longer times, yes, they take damange, but the pack is self-balancing, each charge and discharge they come closer and closer together.

poor cooling
SPT is just 2 x endcaps and then regular shrinktubing, so its actually less material then your standard lipo.

[kgfly]

Great info, thanks guys. If I ever get a bigger heli it looks like A123 will suit me well.

[MrMel]

Z50A-800, 14T

Didnt like it, bogging pretty much, quite high mah draw, im going back to the Actro or Neu.

Of course, it could like a 13T better, dont know if that is the case or not.

http://www.dacsa.net/heli/t600/a123/z50-a123.jpg

[MrMel]

I got something that could be called a glitch today, either because of the Governor or a badly made battery, (im using a DX7), however, I had the eagletree connected, it showed nothing on the voltage, so I suspect the governor.

Hmm, they are out of town so I will disconnect that until I get some info from them (aerospire)

Did a test with the CC governor, it works pretty good actually, little more bogging then the e-Governor, but that was expected.


However, during testing, I forgot and switched to idle up while I still had some little throttle, so it went from about 1000 RPM to 2600RPM in a hardbeat, gear helt (running tight mesh), but I hit 3400 watts and 102 amps! :WOW

Battery held, continued supply nice power for the next few minutes :D