E640 setup power setup and suggestions needed

[phoenixheli]

I'm trying to get some numbers on average current draws on 12S to get a rough idea of flight times.

E640 FB:
450KV hk3-4035 (75A continuous)
94T slant main
10T slant pinion
1700rpm at 80% efficiency
2x 5000mAh 20C in 12S config (100A continuous)
CC Edge HV 80? 120? 80A good match for the motor 120A for more head room
CC Bec Pro
640mm rotortech or funkey fg
Flying style is sport (moderate 3d)

Thanks for the input.

[Dennis P]

I can give you some ideas on flight times but I have a question. How are you mounting the 5000mah 6s packs.My 3300 6s and 4000 5s fit with minimal room up into the servo tray area.
I am flying a 400kv Hacker A50 on 12s 3300s with 660mm blades at 1760 with the 10 tooth slant and I use 75% in 6min 30 secs .My flying is quite varied usually throughout a flight but consumtion is very consistent.I was flying with 690s at 1660 with 7:00 minute flights and 72% usage on average.
Not to pick on you Phoenix but why does everyone want to put big heavy 700 size packs in there 600? I love the light feel of my 600 with the bigger blades.I do not want a heavy feeling heli with smaller blades.

[Furious Predator]

what type of flying do you do? From what I can tell it seems like your power setup is meant more for putting around as a beginner.

If you plan to do sport/3D I would recommend the setup I currently use, or one similar.

I use the Scorpion 4035-530KV motor running the 94/13 tooth helical gear combo. The 10 tooth you plan to use at your KV rating is way too low for any kind of an aggressive setup. Also note, if you plan to use a motor with a 6mm shaft, you will have no choice but to use the helical setup, as the stock straight pinion uses a 5mm shaft...makes sense, but not something I was prepared for when building my kit.

I use a castle creations 120HV, according to its logs, i will hit peak temps of around 184F, and use up to 96% or so of its output capacity...of course that is running 2300 rpm and hauling butt! That still does not leave a lot of room for error, I would personally not use anything less then a 120amp esc.

I generally run 2100rpm like my nitro for 99% of the flying I do, i'll switch to 2300 and go balls to the wall just for fun to show people what it can do.

I am also using the same 12S 3300mAh setup Dennis has, it is working great for me so far. Running 2100rpm I am getting 5 to 5.5 minutes depending what I am doing. Cranking it up to 2300rpm for the duration of the flight sucks it back to about 4 minutes.

I also run the CC 20 amp BEC, it is a very nice little unit, so far have them on two machines and they perform very well. I have already ordered two more to operate the rest of my fleet with them.

[phoenixheli]

I'm building up expectations of what can be done with the e640 lower rpm and long flight within the sport envelope. I haven't built a 600 or 700 size helicopter previously and my experience is limited to 550 or .30 size.

I'm trying to accomplish what I had done with a swift 16 I had previously. I got 10-12 minutes of sport flight using 4800mAh 6S and then 6-8 minutes using 3700mAh 5S. The whole intention of considering the e640 is visibility and potential for a non professional ap setup. Since I don't know where century is heading with the remaining swift line, I want to move to a late model such as the radikal series.

As far as using 12S 5000mAh, using 12S is more efficient and combine the gearing setup for a lower 1600-1800 h/s I guess would give pretty decent 10-15 minutes flights. Since most pilots owning the e640 fly hard 3d, it is difficult to extract information for us long and slow types. Other pilots have used 12S 5000mAh setup that will fit inside the tray and frame rails, but I have not received a definitive dimension on them.

Thanks for the input so far, hopefully I can get some more info on lower h/s setup.

[Dennis P]

Well Phoenix you just had to say the 6s 5000 thing so I had to actually see if it can be done.I pulled a new Thor 5000 6s 35c off the shelf and I had a empty tray laying around and I strapped it down with the thin Century strap with the wires facing rearward. I could not get it started. I then just put the plate in and tried sliding the battery into the frt .It will fit but there is no room for a strap around the sides and somehow you would have to use double sided tape to mount it to the tray and make it so you have enough space so the tray will engage into the rails as the pack will hit the rails as it is as wide as the tray.As for what to do with the rear pack and the wires I have no idea as there is no room for the wires.I am sure it can be done and I will not try and discourage you on the project . I do think a E640 setup with 640s and a headspeed of lets say 1550 on 3300 12s would get you close to 10 minutes ,so if you look for 3700 packs or something a bit smaller than the 5000s you may still be able to mount them easily and get your full 10 minutes plus.

[phoenixheli]

Thanks for the additional info. I'm thinking too that lower C packs in the 20-30C range are usually a little more slim than say 40-60C. Naturally I don't need such high continuous current. An hk3-4035-450 has a max continuous of 75A. Perhaps a 30C 4000mAh would be appropriate and match well with the motor, since it would be 120A continuous as well as more likely to fit.

Could I trouble you to measure the space between the frame rails, the base battery tray to base of frame and the length front to back? Measures in mm would work out since pack dimensions are given in mm anyhow.

So far I've only bought a new bec pro, with castle link and castle quick connect. Motor is next on the list, but I want to experiment with an x-era 450kv motor as an alternative to the hk3-4035-450, so a choice needs to be made there as well.

Thanks

[phoenixheli]

Just thought of another question since you use a bec pro as well. Did you wire the pro across 12S or just one side off 6S? I've heard that it is wise to wire the pro off the 6S side, instead of 12S. I know how to properly wire when splitting across the 6S side. Any thoughts or issues with the bec across 12S?

[Dennis P]

I will get you the measurments later .As for a BEC pro I am the wrong guy to ask as I would not put one in my helis. I run Western robotics becs only.

[Digger1973]

Originally Posted by Dennis P

I will get you the measurments later .As for a BEC pro I am the wrong guy to ask as I would not put one in my helis. I run Western robotics becs only.

+1 on wr Hercules super bec g2 or the pro. Mine works very well and the fail on switch for it is nice.

Sent from my HTC One V using Tapatalk 2

[Furious Predator]

if your pulling off 12S on the BEC rather then 6S, you will have less amps available to use and the bec will heat up more.

That being said, I do not have any issues running 12S on my bec, it does not get too hot and handles the power requirements on my E640 just fine.

That said, it does run much cooler on my 550 running 6S.

I guess the down side to pulling off one 6S lipo while running a 12S, is you would draw more power from one battery, personally I prefer to keep them synchronized. But in the scheme of things it may only be as little as 100mah or so (im guessing) for that flight...drop in a bucket for that the battery can handle.

Perhaps if you are after efficiency, which it seems you are, then running the bec off a 6S would be the way to go....less heat is produced.

[Dennis P]

Here is what they rate the BEC Pro outputs at with different input voltages. As Furious Predator mentioned the output drops as input voltage rises.All the early ones that burnt seemed to be wired into 12s so everyone started going to just 6s . The other brand will do the full amperage at 14s but at a higher cost!

Includes:
- CC BEC Pro High Output Switching BEC with connectors and instruction sheet

Physical Specs:
- Length: 1.69" (43mm)
- Width: 1.3" (33mm)
- Height: 0.94" (24mm)
- Weight (w/o wires): 1 oz (29 g)

Power Specs:
- Max Input: 12S LiPo (50.4V)
- Adjustable Output Voltage: 4.8V-12.5V
- Max Output Current: 20 Amps peak
- Max Continuous Current:
-- @ 16V Input = 15A Continuous
-- @ 24V Input = 13A Continuous
-- @ 32V Input = 11A Continuous
-- @ 40V Input = 9A Continuous
-- @ 48V Input = 8A Continuous

[Digger1973]

Here are the features of the wr bec pro. Your servo's plug directly into the wr bec which plugs in via 4 jumper cables to your rx or fbl unit.

SPECIFICATIONS:

FEATURES:

Height ------ 23 mm

lSuper high efficiency 5.2V, 6V, 7.4V Width ------ 35 mmand 8.2V selectable voltage regulator.Length ----- 56 mmlWide input voltage range from 9V to 75.6VWeight ----- 36 grams(3-18 LiPo Cells). Min. 12V input for 7.4/8.2V applications.lHigh current capability of 16 Amps continuous 22 Amps peak with proper ventilationlHigh power output that handles multiple servos with built in power bus system that allows for direct servo connectionslBuilt in battery reverse polarity, currentoverload protectionlBuilt in digital power on/off enable port (External switch sold seperately)lHigh quality patented power inductor

[Furious Predator]

In the past I have done tests where I have drawn a measured load from a regulator setup to compare its real world performance to the rated one...

Most of the time they failed misserably, the worst offender was the Duralite regulator rated for a constant (not burst!) load of 7.5 amps...if you were to draw only 2.0amps, it would rapidly get burning hot, no way it will handle 7.5 amps steady.

I have a couple more CC BEC's that just came in, I'm going to see if i can get some time to connect them to 12 and 6S setups and draw the rated load, and measure heat sink temps..will probably do it with zero air flow, and measured air flow.

Ever since my initial tests years ago I have always been a little cautious of the ratings these devices are given.

I also have a scope I can connect to the output and see if it can measure any kind of ripple.

Just because I am a nerd!

[phoenixheli]

I recall someone doing tests with various input and output on the bec pro. Cant remember who or what thread that was on.

I'm curious if anyone has used an xera motor in their e640. I'm looking at the 4030 3y and needed some thoughts on it.

Thanks