Recommended Battery

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refractions
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Location: Scotter, Lincolnshire, UK

Recommended Battery

Post by refractions »

Hi,

I am running a quad with the following:

rctimer 930Kv motors
rctime 30A esc`s
Paris V4 board with WM+, BMA180


I have calibrated my esc`s, set my mid, low, high trims.

I currently have a 4000Mah 3 Cell Lipo, but it seems that my quad only want to lift off with almost full power. The battery only last about 3 mins from a full balanced charge.

Any suggestions for another battery, or should i be looking at another cause?

Previous to this - my quad was totally uncontrollable.

When it did lift off, it was all over the place - hate to think of the number of props i have been through. This seems to have been solved by moving the vcc supply for the WM+ from pin 12( +4.5v) to the 3.3v supply, but havent really had a chance to check as i now have this battery issue.

Many thanks

Iain

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Hamburger
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Re: Recommended Battery

Post by Hamburger »

I have no experience with these motors, but does not sound likely.
What is the weight of your copter?
Did you calibrate the ESCs?

refractions
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Location: Scotter, Lincolnshire, UK

Re: Recommended Battery

Post by refractions »

Hi,

Just got back in from work. ESC`s are all calibrated with min and max throttle. Just weight quad - 1077 grams. Think I need to increase the Kv of my motors. Would this also explain why its totally unstable?

Many thanks

Iain

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Hamburger
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Re: Recommended Battery

Post by Hamburger »

check the motor specs. What thrust does each give with which prop?
Do you use similar prop?

PatrikE
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Re: Recommended Battery

Post by PatrikE »

When youhave low KV you might have to use bigger propeller or higher voltage.

10" works god on 1000-1100kv.


Calculate your setup on.
http://www.ecalc.ch/xcoptercalc_e.htm?ecalc

Your setup shows a warning.
* max. power over the limit of the motor. Please check the limits! *
* For good maneuverability you need Throttle of less than 80% *

refractions
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Location: Scotter, Lincolnshire, UK

Re: Recommended Battery

Post by refractions »

Many thanks for all the replies.

Specs for my motor dosent give any thrust values. Current props I have tried are 10x4.5 & 8x4.5.

10x4.5 give - * max. power over the limit of the motor. Please check the limits! *
8x4.5 give - * For good maneuverability you need Throttle of less than 80% *

I have just found out the weight of my frame alone is 600g.

Think I might look at another frame as this is my current one, any suggestions?

frame.jpg
(82.77 KiB) Not downloaded yet



Iain

KeesvR
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Re: Recommended Battery

Post by KeesvR »

Use a lighter lipo around 200g with the 10x4.5 props.

refractions
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Re: Recommended Battery

Post by refractions »

Any suggestions on Lipo type?

Many thanks to eveyone for all the help so far.

Getting a bit confused with all the options now, as totally new to all this - electronics engineer by trade. Current config is:

Lipo Battery 4000Mah 3S 15C
RCTimer 2826-15 Motors
RCTimer 30A ESC`s
Paris V4 board with WM+, BMA180, HMC5883L, BMP085
frame from here :
http://www.ebay.co.uk/itm/RC-DIY-FPV-X450-Glass-Fiber-MultiCopter-Folding-Frame-KK-MK-QuadCopter-Xcopter-/120818180858?pt=LH_DefaultDomain_0&hash=item1c215322fa

Complete quad weight is around 1077 grams.

I have tried both 10x4.5 and 8x4.5 props.

The quad was totally uncontrollable, until the issue with the battery only holding charge for about 3 mins from a full balanced charge. I thought this might be causing me the stability issues?

I am using the default PID`s from multiwiicopter.com, but have reduced the rc expo to .60 as suggested from another member.

Seriously thinking of either throwing in the towel, or starting again with another frame, motors and esc`s.

Please help as its driving me mad seeing all the other quad videos where they lift off, and although not completely stable are flyable - would be fantastic to get to this position.

Many thanks in advance.

Iain

Pyrofer
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Re: Recommended Battery

Post by Pyrofer »

Ive got 10" 4.5 props and 1200kv 135w motors, I can tell you it flies well!
I had a Turnigy 2200mah 11.1v battery, at 180g.
Total weight was about 900g. Watch the total weight its easy to get it too heavy to fly.
If your frame is 600g, its about 2 or 3 times too heavy. Trim it DOWN. Any way you can.
That link says the empty weight of the frame is 200g, not 600g. Weight your complete quad and see what it is.
If its over 1kg, its probably too heavy.

refractions
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Re: Recommended Battery

Post by refractions »

Hi Pyrofer,

Many thanks for the info. Just checked again and the total weight is 1080 grams. I can reduce the weight of the frame i`m afraid, so i`m in the market for another one - cheaper than starting again from scratch. Just found this one:

http://www.ebay.co.uk/itm/Scarab-600-4-FibreGlass-Aluminium-Quadcopter-600mm-Dia-KKBoard-HK-Board-/230772853674?pt=UK_ToysGames_RadioControlled_JN&hash=item35bb224baa

Do you think this will be any good, or possibly look at the Hex frames?

Many thanks again.

Iain

PatrikE
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Re: Recommended Battery

Post by PatrikE »

15C battery can be another problem.
15*4A=60 amp that it can deliver.

refractions
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Re: Recommended Battery

Post by refractions »


Pyrofer
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Re: Recommended Battery

Post by Pyrofer »

That frame seems ok but its specified weight is more than your original frame according to the provided stats, so It may make things worse.

1080g is very heavy. You might want to try a smaller lighter battery, at that weight the fly time will not be reduced a lot and you should be able to get off the ground at least.
Turnigy 2200mah 11.1v 25C packs are around 180g and that's what I have been flying with so far. I didn't see the low battery rating before. Hopefully with the new 20C you should get in the air, if not you might want to consider a current sensor to see if its the limiting factor or not, but a 25C like I have lifts mine no problems.

What I recommend is taking the whole quad apart (I know, I know) and weighing all the parts on accurate scales.
Something is amiss as I can't see how you made it to 1080g!

Your motors claim to be lighter than mine, your frame claims to be lighter, I have no idea where this extra weight is coming from!

refractions
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Joined: Thu Dec 01, 2011 8:55 pm
Location: Scotter, Lincolnshire, UK

Re: Recommended Battery

Post by refractions »

Hi Pyrofer,

Funny - I did just that last night :) Decided to take my entire quad apart - bascially because my wife has bought me a new frame :) Didnt have to do anything either - tho i can see a shopping trip or dinner being suggested :)

I have emailed the company I purchased the frame from as it is 605g not 200g as stated on their listing. My new battery arrived today, and I cant believe how small and light it is compared to my 4000mah one!!!

Just waiting for the new frame to arrive now, and thinking how to alter the old one to reduce the weight to use as a "spare".

Many thanks to all for the suggestions and help. I will update when new frame arrives.

The wife has also just ordered some digital scales for her business - will come in handy :)

Thanks again to all.

Iain

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captaingeek
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Re: Recommended Battery

Post by captaingeek »

Also - watch the RCT ESC's. I think they somtimes loose the throttle max end points or arbitrarily decide to reset it.

refractions
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Re: Recommended Battery

Post by refractions »

captaingeek wrote:Also - watch the RCT ESC's. I think they somtimes loose the throttle max end points or arbitrarily decide to reset it.


I have flashed them with Simon Kirby's "tgy" firmware. Would this solve the issues with loosing end points?

Iain

Pyrofer
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Re: Recommended Battery

Post by Pyrofer »

Most of the time weight is over estimated. Saying a 600g frame is 200g is terrible!

I would try for your money back on that.

Glad to hear things are getting sorted, with a lighter frame and battery you should shoot off into the air rapidly.
(start with gentle throttle please!)

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