6S power system

[mfremont]

I'm just getting started with my E5 build. I decided give 6S a try with 556s just to do something a little different than the 12S Trex 600 I've been flying for the past few years.

For the power system I have the following on order:

KDE 550XF-1200 G3
Castle Edge 120 HV
WR Super Mini BEC G2

I plan to use the Castle gov, and my existing 2600 25C Spyder packs in a 6S2P configuration to start with, but I'll order some larger capacity packs to run 6S1P soon. Just not sure what capacity and C rating to start with.

How many folks have found that they prefer to sacrifice capacity in order to achieve a lighter AUW, i.e. 4400 mAh or similar instead of 5000 mAh?

When you downsize capacity are you also increasing the C rating?

I realize C ratings are often suspect, and the motor itself is a big part of the equation, but what did you find works best?

[curmudgeon]

I tried both the 5000mah packs and the 4400 to 4500mah packs.  The smaller and lighter 4400 to 4500mah packs make the helicopter feel more nimble.


Since you are using the Castle ESC, you may want to consider the slightly more powerful KDE 600XF-1100 motor.  It weighs 50g more than the newer KDE 550XF-1200 motor, but it is a proven motor for this helicopter.

[Rodney Kirstine]

I think the specs on that new 550 g3 motor make it a definite good candidate.  Another one you might want to consider is the Savox 1200kv motor.  It's on sale for $90 right now.

As for battery packs, I run 4400mah 30C and 5000mah 40C packs.  I think when I have to buy new packs I will go with 4400mah 40C or even a higher C rating. I like my smaller packs but they get pretty warm while the bigger ones come down nice and cool.

Sent from my MotoX via Tapatalk2

[Ross Lawton]

Hi mfremont,

I generally pick packs on the balance of machine when the build is complete so the machine will balance perfectly. You will find that there is a huge difference between different brands of lipos. Some 5000mah 6S packs will be lighter/heavier than another manufacturers packs and careful selection can offer you a higher capacity and better C rating with a lighter weight.

At the moment i run a mixture of Optipower Ultra 4300 6S 50C packs and GensAce 4400 6S 60C packs in both my E5 and E7se. The GensAce are a little lighter for a slightly higher capacity and C rating compared to the Optipowers, but both perform exceptionally well.

Hope this helps,
Ross

[Rodney Kirstine]

I took a look again at the specs of the KDE 550XF-1200 G3 motor and it looks like the shaft is too short (25mm) to reach the support bearing in the E5.

[Chris Sexton]

I second that, if you are going to use a KDE, get the new 600XF G3. Shaft is long enough and has all the power you could want.

The Scorpion 4025-1100 is a good option too.

[mfremont]

Thanks for the feedback, and I appreciate the sharp eyes.

KDE confirmed earlier in the month that they plan to introduce a version of the 550XF with a longer shaft, and they offered to replace the shaft with one suitable for the E5 if I ordered before that version is officially introduced. They're not expecting to receive a new batch of motors until 4/30, so I suppose I could still change my mind.

Your suggestions have prompted me to run a few more calculations with eCalc and it seems like the 550XF and 600XF are closer in estimated power:weight and efficiency than I realized. 1100kV gives me a bit more of a useful range of gearing options.

Hmmm.