cjennjr

I should know this, but I'll ask anway. What is the difference btwn a 1800mah 15c lipo and a 1800mah 20c lipo. I already had the 15c for my Raptor, and I want to use it with the Belt CP. My guess is the voltage going to the helo, although I don't think flying time is affected.

gnd2

Nope not voltage. Voltage depends on the number of cells in series, i.e. 2S or 3S packs.

15C and 20C refers to how much discharge current the pack can supply. Basically multiply the capacity by the C rating, so an 1800mAH pack rated for 15C can deliver up to 27A. 20C means it can deliver up to 36A.

You want the C rating of the pack to be high enough to supply the current demands of the motor/ESC you're using. Too low and it may overheat and puff up.

dknovick

The 'C' rating is the amount of current a battery can supply, with 'C' being the capacity of the battery.

So a 1800mAh 15C battery can supply 1800*15 = 27000mA or 27A (max)
A 1800mAh 20C battery can supply 1800*20 = 36000mA or 36A (max)

for similar batteries (2S, 3S, etc), the voltage remains the same, the 'C' rating determines the maximum amount of current you can draw from the battery.

For the same heli, flying time will remain the same. You basically have to know how much (maximum) current your heli draws in flight so that you don't stave it. If you heli draws 15A, then either battery will work. If you heli draws 30A, the 15C battery will "starve" it (the battery won't be able to supply enough current).

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I was wondering about this also, so let me see if i got this straight.

I have the Mini Titan with the stock TT motor and the Ace BL-40 amp ESC, I'm using three CellPro Revolution 3S 2100 mAh lipo's, The Graph in the instructions says that the CellPro 3S 2100mAh is rated at 18C so that would look something like this

18 X 2100 = 37 Amps

Am i correct ?

If so then i should be good to go with the lipo's i'm using for my motor and 40 amp ESC correct.

Thanks

dknovick

37.8A

Your ESC is rated for 40A, so as long as your Mini Titan doesn't pull 37.9 - 40A (just above the battery limit and below the ESC rating), you are good to go!

jp473

It’s Texas and it gets hot. Thought I would start a post about how to dissipate the heat buildup in the batteries while flying. Any thought or mod that other have tried, even the ones that failed are appreciated. No need to completely re invent the wheel. On my B400 it starts to warp the canopy.

jp473

Nube to posting, if this is better for another forum, lat me know.

dknovick

Just how hot is your battery getting? That sounds like it's getting too hot![:@]

As gnd2 points out, maybe you're drawing too much current from your battery.

Other than that:
cut some holes in the canopy to allow better air flow.
try to redirect some of the downwash from the rotor toward the battery.

As for a better place, you might want to just try "Electric RC Helis", you may get more traffic there.

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Thanks dknovick