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Battery C rating question - Masters Pattern

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Battery C rating question - Masters Pattern

Old 07-10-2016, 09:43 AM
  #26  
OhD
 
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Woodie is right, about managing energy. A good pilot can get the same performance at the end of flight as he gets at the beginning by how he handles the throttle, but he must have enough energy and enough power at the end of the flight when battery voltage has dropped. The power developed by our brushless motor propulsion systems is a function of the voltage to the motor and the Kv of the motor. So to get repeatable power the voltage must be consistent. Typically, our setups produce more than enough power at the beginning of flight and not quite enough when we have used 80% of the capacity if we don't manage it properly. Scott's setup sounds like he doesn't have enough power when his pack is at 50% of capacity. So he needs a means of converting the remaining energy to work faster. If he goes to a six cell pack or higher Kv motor he will have more power and will need to figure out how to manage it. He can decide whether to manage it with the stick or the Throttle-Tech.

Jim O
Old 11-10-2016, 03:45 AM
  #27  
Pattern_is_Fun
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Thanks for the comments. I have decided to go with a 6S 25C pack and run 2 throttle curves. The first throttle curve will limit the full throttle to 80% of max battery. (I actually use a watt meter and make the watts the same as my 5S pack). l set the second throttle curve so full throttle is 100% of remaining battery power. When I then get to a certain point in my pattern I switch to throttle curve 2, giving me the extra power I need to complete the pattern. I should note that I use the throttle (and throttle curve) a lot to keep constant speed and while I may have more voltage/current/power, I don't fly at max throttle. My goal is to use the throttle management the same throughout the flight with no change in airplane performance. If this does not work out, the throttle-tech will be the second choice with the 6S pack. I have run preliminary tests and the 2 throttle curves seems to work fine.
Old 11-04-2019, 02:48 PM
  #28  
Pattern_is_Fun
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While this is very old I'll give you my conclusions based on actual flights. I have tried 5S, 5000mah, 20C, 6S 4500mah 25, 30 and 40C packs. The 6S 4500mah 40C packs work much better than the 25C and the battery capacity upon landing has gone from 18% left (25C) to 35% left (40C). 5S worked fine, but really not for competition in Masters Class. 6S much better - and going from 25C to 40C with the same 4500mah battery gives me better overhead having 35% left. Same throttle curve, same style of flying - but I may have changed the throttle curve - down a bit at 50%, 70%, 85% but don't recall for sure. I'm on my 3rd season with the 40C batteries, where the 20C were having trouble after 2 seasons of flying. No signs of battery swelling and all packs were Zippy Compact cells. Weight between the 5000's and the 4500's is close as the 5000's were 20C and the 4500's are 40C. The 6S, 4500mah, 40C's work great and really tune my flying style with the plane / weight and throttle curve and prop.
Old 11-05-2019, 06:07 AM
  #29  
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If you can afford the weight penalty, there is no downside to ever flying with a higher C (lower IR) rated battery pack.
Old 11-05-2019, 08:40 AM
  #30  
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There is little weight penalty going from a 5000mah 20c to a 4500 40c. I agree though for the same capacity battery the larger C rating will be heavier. Thus the reason to drop to a 4500 pack. Physical size is basically the same (in my example).

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