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Lipos with higher C then ESC

Old 05-01-2019, 08:27 PM
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jangodog
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Default Lipos with higher C then ESC

As mentioned is it safe to buy lipos with higher C rating then the build in ESC? My foamie has an 30C amp ESC but the lipos i'm looking at has 45C.
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Old 05-01-2019, 08:41 PM
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pmullen503
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ESCs don't have a C rating, just amps. If your motor/prop combination draws less than the ESC amp rating* you'll be OK regardless of the battery.

*I run an ESC rated 20 to 30% higher than my anticipated max amp draw, especially if it is an inexpensive Chinese one.
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Old 05-01-2019, 08:43 PM
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jangodog
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So the C rating doesn't matter 20 or 45C lipos will do okay with this ECS with the recommended prop?
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Old 05-01-2019, 10:52 PM
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pmullen503
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Originally Posted by jangodog View Post
So the C rating doesn't matter 20 or 45C lipos will do okay with this ECS with the recommended prop?
The C rating of a battery refers to the theoretical current it can put out. So a 20 C 2200 mAh battery can theoretically put out 44 amps, a 40C, 88 amps. But if your motor will only draw 20 amps, as long as the battery can supply it that's all that will be drawn through the ESC.
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Old 05-01-2019, 10:56 PM
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jangodog
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Ok, thank's. I'll get the 45C lipos then
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Old 05-02-2019, 08:46 AM
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solentlife
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Simple rule I follow :

ESC should be at least 30% higher max rate than the motor max demand

LiPo should have at least 2x the max amp rating based on capacity x C rating.

That means in the case of a 20A motor :

ESC of at least 26A ... so that means a 30A ESC

LiPo capable of 40A ... so in the case of a 2000mAh pack ... that would be a 40 / 2 = 20C pack as minimum ... I would be using a 25C or more.

Last note : As you go higher in C rating - the weight of the pack increases. A matter that should not be ignored. In many cases it may be better to increase capacity instead of C rating - to get more flight time for same increase in weight. Remember amp capability of the LiPo is based on BOTH C rating and Capacity.
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Old 05-02-2019, 07:36 PM
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ron_van_sommeren
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Wires, controllers and motors only 'feel' voltage and current. C-rating is only useful for comparing batteries of same capacity.
More about C-rating, and manufacturer ... eeeh ... optimism in this active test-thread, with decent and standarised test-equipment
Battery Load Test Comparisons - RCG


It is a good practice to have some headroom built in.
About derating motors, controllers, batteries, electronics in general:
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