Want ESC for minimum 8s a123 / 7s Lipo.

[csell]

I am a newbee and my T-rex 600 just flew its first fligth.

To get a loot of flying time I consider to bay

2 new 6s 4900-5000 mAh lipo packs

or

4 dewalt a123 packs = 5 psc 8s a123 packs + a new ESC.

I hope that five 8s a123 packs will provide more and nearly constant flying time.

But I don't think the stock align ESC can handle the voltage of 8s a123.

Can any confirm that I need a new ESC that can handle minimum 8 x 3.6 volt = 28.8 volt equal minimum 7 Lipo ( 7 x 4,2 = 29,4 volt ).

Any advice or suggestion to what ESC to try is very welcome?

I live in Europe and support for local products is better,
but I will consider baying from all over the world.

Will it be better if I get a 600XL motor insted of the 600L?

Regards Carsten

[uragano47812]

If you want to go >6S you will need to change ESC and the choices are CC85HV or Jazz 55A or 80A. But if you go with CC85HV i read that it has problem with stock align motor but not for sure...

[waelo]

Hello,
I use CC HV85 together with 600L and 10S A123. Works good so far but only running the engine at 75% throttle so it will survive til I get a NEU... :?

[Mercuriell]

No the stock Align ESC is very unhappy with 8S A123 - most likely due to the cell count function. Although the nominal voltage is 29.2V this falls under load to around 24V. Get a CC85 or if you want something a bit cheaper this one does nicely:

http://www.wattsuprc.com.au/product_...p?pid=EW-HV80A.

As far as the motor goes I ran a 600L motor for around 30 flights on A1238S and it seemed happy but one day it smoked out - I had a binding TT at the time so this may have contributed.

[csell]

Hello.

Thanks for all your answers.

I need a new ESC for sure.

Waelo and Mercuriell do you know what kind of fligth times do you got in hovering and ligth beginners flying?

And how can I compare fligth times for 10s a123 running engine at 75% with 8s a123?

Is it better to consider a 600 XL?

Regards Carsten

[Mercuriell]

About 5 mins flying on 8S in light flight - the A123 drop their bundle really quick - over about 20secs towards the end of the charge, so you do have to run them on a timer. They are a bit lighter than the lipos so I think running two 8S packs in parallel an attractive option - haven't tried 10S A123 yet but I think that is going to be good Of course you can charge 'em up at 4C although I find 2C better and they really don't need balancing - I ended up taking off the taps when I re-heatshrunk my 8S. They reportedly have a long life too - I'm up to about 100 cycles on my oldest pack which is still going strong.

[waelo]

Originally Posted by csell

Hello.

Thanks for all your answers.

I need a new ESC for sure.

Waelo and Mercuriell do you know what kind of fligth times do you got in hovering and ligth beginners flying?

And how can I compare fligth times for 10s a123 running engine at 75% with 8s a123?

Is it better to consider a 600 XL?

Regards Carsten

Hello neighbour :wink:,
I get around 7-8 minutes easy flying with my 10s A123 pack, preatty ok i think. Havent fly it as much as Mercuriell tho, you know we dont have that good flyingweather as they do down under...
Br Johan

[csell]

Hello.

Waelo has 7-8 minutes easy flying with his 10S a123 packs, I don't need more.

I am going to bay some.

Mercuriel, you haven't tried 10S A123 yet but you think that is going to be good.
I paid yesterday for 2 a123 cells I got on a ebay auction, the seller is from Australia, I don't know how many a123 packs you have and how it are asembled, but if you want to try 8s + 2s packs, I can try to get it shipped directly to you?

I just ordered it to learn more about a123 cells, but as I already now have deceided to bay some 10s a123 packs, I don't need it in the near future. If I suddently need 1 or 2 cells I will then ask you to send some to Denmark. I will send you a PM for exchanges of postal adresses.


In selecting the right ESC the best setup will be, if I just can just swap my 6S 4900 mAh FligthPower pack with a 10S a123 pack and may be select another setup in my Futaba 9CHP/FF9 transmitter. I don't know if that is possiable?


As I understand will a lower number of cells gives more current out of the ESC for the same power.

Waelo, how had you limit your setup to 75% power, and can it be done in other ways? Do any know how much power the ESC need to handle under this 75% power setup?

waelo use CC HV85 and Mercuriell use EW-HV80A I will consider both, but I found
JAZZ 55-6-18 for a good prise here in Europe.

Do you think it can handle the large output current when using the 6S Lipo?
Is it a option to consider?

Regards Carsten

[kgfly]

Hey Carsten,

A few figures to consider:

Lipo cell = 4.2V peak, 3.7V nominal, 3.6-3.2V under load
A123 cell = 3.6V peak, 3.3V nominal, 3.0-2.5V under load

6s lipo: 25.2 peak, 22.2 nominal, 21.6-19.2 under load
8s A123: 28.8 peak, 26.4 nominal, 24-20 under load
10s A123: 36 peak, 33 nominal, 30-25 under load

It seems to me that you cannot gear the heli for both 6s lipo and 10s A123 and be in a safe operating range for the ESC. Remember that most (all?) ESCs are inefficient below about 80%. Even under heavy load the 10s A123 minimum output voltage is almost 20% above the maximum for the 6s lipo. Under light load, like when spooling up, it is close to 40% higher. You could try running your ESC at low throttle on the 10s but I don't know how well it would work, you could end up cooking the ESC.

As for the Jazz I think it is too low a rating. 6s lipo @ 55A = ~1200W, 10s A123 @ 55A = ~1400W. A T600 needs 1800-2200W capacity for 3D. I think you need a 75A ESC at least to be safe from overloading/overheating.

[csell]

Hello.

Thanks Kgfly.

I found and read more information for both CC HV85 and EW-HV80A.

I live in Europe and a EW-HV80A + programming card must I order from Australia and I can order a CC HV85 from USA for just 20 US$ more, it is better known in Europe, so I have deceided bay a CC HV85, but what is the problem with CC HV85 and 600L uragano47812 writes about?

When I se you numbers I don't condsider to swap between LIPO and a123 anymore.

I will go for a a123 setup only. But how many a123 cells can I connect to a align stock 600L? I think that is the importent questen. Is it 7s, 8s or 10s? What can you recomend?

When I read about a123 cells in a T-rex 600 some thinks that a 2p setup must be ideal. But I can't find any having succes with it? And I am wondering why.

I don't think it can be to heavy. If I want a 7s2p or 8s2p setup I can have 10 cells ( 700g ) in the battery holder and the remaining 4 ( 280g ) or 6 ( 420g ) mounted underneath in center of gravity. The T-rex 600 can easely carry that weigth.

Can any se what the problem then is?

Regards Carsten