P-Spec minimum discharge rate

[rodneypierce]

Hey guys, Im new to the whole FE thing. Ive ran nitro for years, but just getting into the FE side of things. Im building a P-Spec tunnel with AQU 60 amp esc and AQU2030 motor. My question is, what is the min. discharge rate needed? Ive seen 30c-40c. Can I get away with a 30c discharge for a p-spec build? prop will likely be a 42x55 or 42x66. I know its got to be 4S and 4000-5000mAH. But what about that discharge rating?

Thanks in advance,
Rodney Pierce

[TheShaughnessy]

If you are racing the highest c rating you can afford. Check out dinogylipos.com. Not the cheapest but not the most expensive either and they are some of the best batteries around.

[rodneypierce]

I guess I should have worded it differently perhaps? Is 30c enough? Will there be a noticeable difference between 30 and 40c with a p-spec setup? Can the motor/esc even fully use what a 30c rate will give?

[TheShaughnessy]

It won't be real noticeable till lap 5. I have a set of 40 c batts I run in a p spec cat and they seem to start fading quite noticeably by the end of a heat. Packs are 2 2s 5000 Mah gens ace cells wired in series. 30 c packs will get you going though and you'll finish the race. I just don't believe manufactures ratings. 30 c 5000 Mah should be capable of 150 amp discharge which is way more then a p spec set up will draw. Just not sure how long they will actually provide that 150 amps or at what voltage. Voltage sag is very real.

[rodneypierce]

Thanks man! So sounds like it would be a safe bet to get atleast 40c discharge then.

[Namba328]

Rodney to be honest 50c is roughly the best all around for someone starting out. I run a set of 40-50c 2s turnigy packs in series and like Shaughnessy said even i tend to see a drop towards the end of the heat but not as severe as the gens ace packs that i used to have. So if you go with 50c or higher you should be set.

[Fluid]

Don't get stuck on the "C" rating alone - the manufacturer matters too. I've run 35C/5000mAh Hyperions and they do not fade at all towards the end of a 6-lap one-mile heat. Hyperions' "C" and capacity ratings are accurate, Turnigy's not so much. But if you must buy Turnigys, get the highest "C" rating you can find.



.

[rodneypierce]

alright, thanks guys!!

Fluid, I dont plan to run Hyperions, as I dont think they are needed for what Im looking to do. Its more of just a "fun run around the pond with the guys" tunnel. Not sure if it will ever even see a race or not. But I usually tend to take things to the extreme, and nothing is ever good enough :)

But, to start off with I dont want to drop all of that cash on Hyperions.

[Fluid]

No problem, spend your money as you want. My point was that Turnigy ratings are not accurate. If you think you need a 35C pack, then get a 65C Turnigy pack.



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[LuckyDuc]

Hey Rodney!

You gonna bring it to any D-4 races this summer?

Sean

[rodneypierce]

Sean, probably not. I dont know how many races I will be able to attend with the new work schedule. With any luck I will be working most weekends (I know that sounds crazy right? but thats where I make the big money)

Might not be able to make a single race. We will just have to see.

[Brushless55]

Don't get stuck on the "C" rating alone - the manufacturer matters too. I've run 35C/5000mAh Hyperions and they do not fade at all towards the end of a 6-lap one-mile heat. Hyperions' "C" and capacity ratings are accurate, Turnigy's not so much. But if you must buy Turnigys, get the highest "C" rating you can find.



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agreed
with Turningy packs, 40C min

[rodneypierce]

I was actually looking at the Zippy Flight Max 45c 5000mah lipo's to be honest. From my reading, appears they have a better track record then the turnigy's

[Brushless55]

those should do well

[Rumdog]

Simple answer.. Yes. 30c is plenty for that setup. In likely any brand. I ran 20c cells in a ul-1 with no issues running a x440/3. And those were "cheap" Turnigy packs.