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        Question New Low IR Lipos Cells

#1 nxtdoor Jul 13, 2009 06:47 PM

New Low IR Lipos Cells
 
I am trying to decide on batteries for a new plane and the performance of these new packs(Neu and Hyperion G3) makes me pause on what "s" configuration to use.

I have run the motor/prop combo (Neu 1512/1.5y/6.7 18.5 x12 RFM) with 2s 2200 TP Extremes in 6s series (was just a test, will be using higher mah) and it pulls 70amps and gives me 1200 watts output which is good for my Stratos E. I would expect the amp draw will decline a little when the prop unloads in the air.

I don't know how the TP Extremes (about a year old, very little cycles) compare in performance to the newer cells.

Any comments would be appreciated.

Jeff

#2 sneu Jul 13, 2009 07:00 PM

Our SP series are 40/70C and work great for silly power. They come in 2000,2600,3000 and 3700mah packs. http://www.neumotors.com/Site/Battery_Specs.html

Some people on this forum have been known to abuse the SP3700s at 400 amps:)

Steve Neu

#3 nxtdoor Jul 13, 2009 07:46 PM

Thanks for the reply Steve. I am aware of the silly power available. What I want to know is will they up the amperage considerably compared to the TP Extremes from a year ago. I have read some people say they have to reduce the number of cells in series due to the increase in power from the newer cells. This is what I am trying to determine. I have a Phoenix 80 controller and want to try and stay around 80 amps max. The extremes at 6s were pulling 70 amps on the bench.

Jeff

#4 sayno2glo Jul 14, 2009 01:30 AM

Hi,
It depends how bad your batteries have become in a year. My one or two years old Polyquest 30C are so bad compared to new 35C G3 that I need 6s vs. 5s to make same power. I did a bentch test while ago. With old 30C batts I was at 800W and with the new 35C batts the same setup gave 1800W. That might be the most extreme difference ever but you can't really know until you test.
Even if the test show significant difference you can still preheat the old pack and choose larger prop and be in the same ball park.

#5 tjarko Jul 15, 2009 01:49 PM

Ri value for NEU3000SP cells ?
 
Steve do you have more info about these 40 C cells?

Discharge curves at 40C or Ri values?

Tjarko

#6 jjmouris Jul 15, 2009 05:41 PM

TP Extreme or Extreme V2 ?! Big difference!

I would say the new Neu 40C are equal to TP Pro Power P30 in terms of voltage / power for a given capacity.

But a CC 80 can probably take double it's rating in short bursts. Or 50% more in not so short bursts.

#7 sneu Jul 15, 2009 07:29 PM

Quote:

Originally Posted by jjmouris

I would say the new Neu 40C are equal to TP Pro Power P30 in terms of voltage / power for a given capacity.

On what do you base that bit of wisdom?

Steve

#8 nxtdoor Jul 15, 2009 07:57 PM

Steve, I tried another test with a warmed (to 95 degrees) 4s PQ3700 (at least a year old, very little use). The starting voltage was 16.8, pulled 75 amps with initial watts at 900 dropping to 850 after about 20 seconds with a loaded voltage of 12.5. How does that compare to one of your SP packs of similar size? Can I expect more performance?

Just ordered some of your 6mm connectors. The 13 ga. wires on the controller have to be changed!

Jeff

#9 biskit Jul 15, 2009 09:10 PM

Measure the voltage of your packs and compare to the data below. Green is Pro Power 30, red is the 35c hyperion packs. Looks like the power increase you'll get boils down to basically what condition your existing packs are in.

See everydayflyer's data here: http://www.rcgroups.com/forums/attac...mentid=2622133

#10 jjmouris Jul 16, 2009 04:04 AM

Quote:

Originally Posted by sneu
On what do you base that bit of wisdom?

Steve

By flying both, comparing the run time and looking at the data on the Unilog.

#11 sneu Jul 16, 2009 08:33 AM

Quote:

Originally Posted by jjmouris
By flying both, comparing the run time and looking at the data on the Unilog.

Really? When did you get some SP3700s?

Steve

#12 jjmouris Jul 16, 2009 09:22 AM

Steve, i didn't. I am comparing whatever Eric had to mine as he flew mine. It was 2S and 3S joined to make 5S?

We also compared again the older 4100mah to the TP V2 3850mah and results showed a slightly higher power from the TP pack despite capacity difference.

In any case the thing that is more important to me is cycle life at constant performance. That is not going to be easy to compare at all.

#13 sneu Jul 16, 2009 10:56 AM

Quote:

Originally Posted by jjmouris
Steve, i didn't. I am comparing whatever Eric had to mine as he flew mine. It was 2S and 3S joined to make 5S?

We also compared again the older 4100mah to the TP V2 3850mah and results showed a slightly higher power from the TP pack despite capacity difference.

In any case the thing that is more important to me is cycle life at constant performance. That is not going to be easy to compare at all.

I think that you would see that the SP3700s 40/70C are step up in power over the earlier cells. On the other hand with limiters what is also important is to have consistent performance from cycle to cycle.

Steve

#14 George Shering Jul 16, 2009 11:52 AM

Quote:

Originally Posted by sneu
I think that you would see that the SP3700s 40/70C are step up in power over the earlier cells. On the other hand with limiters what is also important is to have consistent performance from cycle to cycle.

Steve

A big advantage of the latest cells is that you do not have to pre-heat them. The voltage seems to be the same at the beginning and end, with a slight rise in between. This, as Steve says, helps with consistency.
On the other hand the Germans control their motor run time by changing the pre-heat temperature. I don't think this could be done with the 2009 cells as the voltage is already falling at the end of the run.
My experience is with the Fullymax cells in the Overlander packs.
I have a feeling that most of the 2009 cells are from Fullymax judging by the sizes available????

#15 jjmouris Jul 16, 2009 01:39 PM

George, i was going to build another battery heater but instead i will be making my own hubs to put the blades out further or not, to adjust for the weather. This i think will be much more effective. It seems with the new battery's and their low IR, a small change in prop has big effects on current pulled. Where as in the past the battery needed to be hot to it would give constant power climb vs climb, now it does this anyway.


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