Powering 6 motors.... questions

[XH558]

On my own design Hex I have 6 of these ....

http://www.ebay.co.uk/itm/Emax-CF2822-1200KV-Outrunner-Brushless-Motor-for-RC-Aircraft-Helicopter-/200725089263

I knew nothing about quads etc when I got them and did a bit of brief noodling around research before I got 4 for the quad I built first. I just added 2 more for the Hex and it';s all been fine.

I';ve been getting 6 minutes ish on Turnigy Nano Tech 3s 2200 mah 35~30 Lipo and they get quite warm. I have 4 of those.

10 x 4.5 props.

Just a brief reminder here - I have a very very limited understanding of electrickery - I know that amps and volts and crap exist but I don';t really understand what it all means ... I know that 3s is 11.1v and I think that the more the MAH the more you may be able to get time wise - and as for current load and amps drawn ... forget it   :embarrassed :embarrassed

So I ordered a 4400 Mah Nano Tech as an experiment - and I was quite surprised that it didn';t give me much more flight time and still got quite warm.

Now I';ve had an idea - having read it somewhere here - that it may be a good idea to split the motors and have 3 running off one battery and 3 running off another - or even 2 -2 & 2.

So - questions.

1) How do those motors look for what I';m asking them to do on one battery.
2) Would splitting the load with more batteries make a big difference - taking into account the extra weight of more batteries?
3) Suggestions on how else I might improve things?

[Balders]

I would never run motors off separate batteries.

Only time you';d typically run with two batteries is with them im parallel.

It';s not unusual for a lipo to come down warm, not hot but warm.  Also, make sure you are not over discharging your lipo';s...this can cause them to get abnormally warm too.

[KK1W]

Take this for what it';s worth, remembering I have zero quad experience. I do have experience with electric powered aircraft and other things electronic tho - so maybe it';s worth something. ;D

First +1 to what Balders says  - don';t split the motors between separate packs. If you need more capacity then parallel the packs. Imagine what would happen if you separated the motors/packs and one of the battery packs took a dump because of a bad cell. You';re not going to stay flying!

My gut says the 1200KV motor may be a little stressed out with a 10 x 4.5 prop. The motors and the packs might be happier with a smaller prop, say 9 or even 8".

Without knowing the total amp draw of the six motors at hover it is just shooting in the dark to estimate how long a pack will last. To be honest I';m surprised you';re getting six minutes out of a 2200 pack. Do you know what the pack voltage is when you land after the six minutes? There';s a few different minimum cell voltages out there but if you';re going below 3 volts/cell (9 volts for the pack) that';s not a good thing.

Either borrow or invest in a wattmeter and you won';t be in the dark about what your hex is actually using for power. Here';s a inexpensive example from HK: http://www.hobbyking.com/hobbyking/store/__28713__Turnigy_130A_Watt_Meter_and_Power_Analyzer_UK_Warehouse_.html. Put that in line with the battery, hold down the hex and run up the motors. I';ll bet you';re drawing near 50 to 60 amps in hover. That would probably put you in the 6 - 9 minute flight range depending on throttle management.

I don';t know why your flight times would be similar between the two batteries. You would expect near double as the 4400 is twice the 2200. Maybe the 2200 just can';t supply enough current and discharges slower? Does the hex seem snappier on the 4400?

Hope this helps...

[Balders]

Didn';t have a huge amount of time earlier when I posted so will expand a little now...

I used EXACTLY those motors on my wooden home made hexa frame, using Naza.  I used 10amp Black Mantis esc';s which were perfect, never ever gave me a hint of trouble.

I used to carry my gopro in a gimbal and on a 2300mah 3S had the timer set around 4 1/2 minutes mostly because I do tend to fly some distance and also I don';t like taking too much out of my paacks.  If I knew I would be perhaps need a longer flight time I would parallel my packs, and set the timer closer to 6 minutes, again to make sure I had plenty left in the batteries to get back home if I was some distance out.

Those motors are great on 8" props.  I would NOT try them on 10".  I just use the cheapest Giant Shark 8x4.5 slow flyer plastic props.  Make sure you balance them and also make sure if you use prop adaptors that they are secure on the shafts.  I crashed/broke one hexa due to cheap prop collets.  Video here:

http://youtu.be/JGVnsPLLbZw

[eyeflying]

I too think the problem is with the props. I';d never fit 10" props to any motor that';s rated 1000kv or more.

[XH558]

Some excellent advice/opinions - thanks all - ordered some smaller props - then we';ll see if there';s changes - will report back in due course  ::)