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Old Apr 01, 2011, 06:07 PM
Registered User
El Cajon, CA, USA
Joined Feb 2001
801 Posts
Question
High quality small mAh vs. cheap quality large mAh pack

Iíve got three cheap 6s 5000mAh packs from Turnigy. They all have 20-30 flights on them and they are puffing and the power is starting to drop. I treat them like gold, broke them in properly, and follow all the standard charge/discharge practices (except I never discharge below 70%), and they are never more than just warm.

So Iím in need of new batteries now and was thinking about the new Thunder Power 65C packs. Hereís my question. Assuming my heli pulls a constant amp draw of 35 amps and a burst of 70 amps do you think a 3300 65c ThunderPower pack will outlast (cycle wise) a 5000 Turnigy pack?

I totally understand Iíll have shorter flight times (but the lighter weight should be nice too). I know Iíll be pulling more ďCĒ outta the packs because they are smaller and therefore Iíll be harder on them than the big cheap packs. But do you think Iíll get more cycles out of them?

The cost is considerably more but right now Iím paying $75 bucks for 20 flights and that sucks. If I can get 50 out of the TPís then Iím at almost the same price.
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Old Apr 01, 2011, 06:35 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,736 Posts
Your mileage may vary but I cycled a TP Pro Power 45 2250 mnAh 300 times. Charged at 10A discharged at 40 amps. (17.7C) .

http://www.rcgroups.com/forums/showthread.php?t=1142882
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Old Apr 02, 2011, 11:13 PM
Registered User
El Cajon, CA, USA
Joined Feb 2001
801 Posts
One more quick question.

I typically charge 12-14 hours before a flight. I store them at proper voltage (3.85 volts/cell) for all other times.

Is this fully charged 12 hours on packs? I know it's not ideal but do you think it's that hard on the packs.
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Old Apr 03, 2011, 02:42 AM
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Australia
Joined Nov 2010
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Quote:
Originally Posted by Munch View Post
One more quick question.

I typically charge 12-14 hours before a flight. I store them at proper voltage (3.85 volts/cell) for all other times.

Is this fully charged 12 hours on packs? I know it's not ideal but do you think it's that hard on the packs.
=[
What other option do most of us have? unless you want to get up at 3am the morning you go flying?

Also you dont say what C rating your current batteries have. if you are going to 65c batteries i would imaging you are pulling some serious amps. what did your watt meter say?
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Old Apr 03, 2011, 07:48 AM
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United States, NJ, Frenchtown
Joined Mar 2003
9,112 Posts
Heliguys

You people are really tough on your cells. Most of you that I have talked to NORMALLY run at the burst rating for a lot of the flight. Just a fact of getting the vertical performance they want.

The fact that all are aging equally is good. Maybe yours were not the best ones in a production run ?? Maybe you fly with longer high amp drain than on the ground tests say ??
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Old Apr 03, 2011, 09:41 AM
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Chicago 'burbs
Joined May 2006
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35A is ~10C and 70A is ~ 20C for a 3300 mAHr pack, so that should be loafing for a "real" 65 C pack.
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Old Apr 03, 2011, 11:43 AM
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United States, NJ, Frenchtown
Joined Mar 2003
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Normally as the C rating goes up..... The # of continous & burst cycles goes down.

So you going to a smaller & lighter should equal less cycles. There is just less material to deliver power.

I would think the Helicopter Forums would really help you a lot more. They do try all combinations to get maximum number of lifts per dollar.
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Old Apr 03, 2011, 02:24 PM
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El Cajon, CA, USA
Joined Feb 2001
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Quote:
Originally Posted by Alan Hahn View Post
35A is ~10C and 70A is ~ 20C for a 3300 mAHr pack, so that should be loafing for a "real" 65 C pack.
This is what I was thinking.

I know there is endless discussion (much of it very very good) about what C ratings really mean and ways of standardizing the discussion.

It just strikes me as so odd when I'm "pushing the envelope" by using smaller cells than anybody else and yet I'll be bursting at half of what the continuous rate is. I know I'll have reduced flight times and probablly reduced life cycles but it shouldn't be like 60% reduction in cycles right? I'd expect it to be a reduction of like 8-15% or something.

I want those TP 3300 packs so bad to test my theories but I'm still gunshy from my TP Extreme V2's. They sucked really bad for lifecycles and even though the world is saying these new 45 and 65C batteries are different I'm still scared. I wouldn't be worried about it on a 45-60 dollar battery. It's the fact that I'll be buying 2-3 of these $180 dollar suckers.

Sure do wish I'd have had the forsite to get in on that 25% off sale from a month ago.....
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Old Apr 03, 2011, 02:38 PM
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United States, NJ, Frenchtown
Joined Mar 2003
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Munch

Something else to consider about anything being produced in this LOOONG Depression.
Companies are going to make stuff cheaper for the same price. REALLY TOUGH to know if you are buying the good old cells or newer stuff that is rated by the sales dept.

Good luck.
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