Turnigy blue 25c vs 40c??

[p4ddy]

My 25's are a bit puffy & one is now ******* because I left them for 16 months not on storage. Only now I am annoyed at myself but I can still sustain aileron tic tocs with them lol. I shall get the 40c packs.

[scallybert]

That's true for average c rating, and assuming you fly until the battery is totally depleted. Most people leave 20% in the battery so you would need to divide the answer by 0.8... so 10C would become 12.5C.

That's back to front. If you're only using 80% of the capacity, the time should be 80% smaller for a give C rate discharge. ie you should calculate (80%*60minutes)/flight-time to give the average discharge rate in terms of C.

To try and make this clearer: if you fully discharge the pack in an hour, that's 1C by definition. If you half discharge the pack in half an hour; that's also 1C. So (50%*60minutes)/30minutes=1C => the 80% above is correct.

The problem with that method is that going by the results no one, not even the very hardest flyers, would need any more than 20-25C... and we all know that's just not realistic.

Yes.

However, the calculation is 'correct' - what's debatable is how useful the answer is.

I'd suggest two factors: the manufacturers' overstate their C rating; Some packs don't tolerate bursts of high current well.

[Grumpy]

That's back to front. If you're only using 80% of the capacity, the time should be 80% smaller for a give C rate discharge. ie you should calculate (80%*60minutes)/flight-time to give the average discharge rate in terms of C.

Good point.. You are right, so that reduces 'average' c rate even further. So 10C becomes 8C and the very hardest flyers will be in the 15C-20C range

Which as you say, kinda does show that calculating average C, although technically correct, is of no real use in figuring what actual C rating you need.

[dogbiscuit]

I have both 25 and 40c blues )2600, 5s).... paired up in the 550 the 40's have been great for me, but the 25's die incredibly quickly !!!!!

[p4ddy]

I'm about to order 2 packs but which warehouse is cheapest including postage? I don't want to accidentally go too far as the process seems to be different to the last time I bought from hobby king.

[waveydavey]

Either UK or Germany Paddy. You might get picked up for duty from Hong Kong and for the few quid in question it's not worth it I would say

[milly0812]

I just got 6 x 5000 40c from UK warehouse for £42 each and 7 postage

[cjcj1949]

Don't forget that temperature makes a big difference to performance. Warming to 30 degrees C will lower the ir of all packs. Flying gently for a minute at the start of a flight and then resting for a minute also helps at low battery temperatures also helps.

[p4ddy]

Well I had 2 40c in my cart last night £85 posted, got to paypal then decided it's a lot of money to spend on 2 batteries & I'll hold fire for a bit as I don't know if the enthusiasm is fully there to fly still. That was a wise decision as I just went to the field & crashed again breaking my new tail blades bending another link. The tail control rod screw fell out, still at least the nylon screws saved the frames. But it's left me feeling like I cannot be bothered again. I might snap out of it in a minute?