G'day DIY Drones,

I have a question about batteries, yes, I know this has been done to death, but I would like some real world experiences rather than the math.  

I have used the search bar but I guess I am not using the right keywords, hence the reason for this post.

I am considering using 1 10000mah 4s instead of 2 5000mah 4s batteries to get more flight time from my 690mm photography rig.

A bigger battery of the same C rating or close to it.

Here is the math (feel free to correct me if I'm wrong)

2 x 5000mah 4s at 25 C = 125 max amp draw and has 10000mah. Weight, approx 1300g

1 x 10000mah 4s at 25 C = 250 max amp draw and has 10000mah. Weight, approx 800-850g

I only need about 115 max amps so both will do the job.

My question is about flight time and battery voltage sag.

I don't want theory but real world experience please.

Will the 10A, lighter battery give me more flight time because of the weight saving or will the voltage drop off sooner because it is only a single battery?

Another way to put it would be, would the 2 5A batteries hold the voltage longer than the 1 10A battery given the same flight situations?

Another way to put it is, are two batteries that equal the one in MAh, better?

I hope I am making sense here 

Cheers

Aussie

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Hi Aussie,

I have re read the your opening posts and can see that you asked for a non theory discussion. Please accept my sincere apologies for my part in the thread drift. I have deleted all of my theory related posts in order to get the thread back on track. So to your questions;



1. I use one battery as it's easier to keep track ang log it's performance during it's life, the aircraft was designed around a single pack to maximise efficiency/ flight times.

2. That sounds like a normal flight time for a hex of that weight, so many variables to comment further without a detailed description of your setup.

3. That failsafe is about right, absolute minimum is 3v per cell but there is a rapid drop off around 3.7 to 3.3 so it is best not to go too low. If you see the post by Brad Hughey in the thread below you will see it exlplained nicely.

http://diydrones.com/forum/topics/lowest-safe-voltage-per-cell-on-lipo

G'day Joe,

Thanks for your input and thanks for answering each of my questions.  All put into my memory bank and processed to the best of my ability. 

I'm now leaning more toward the use of one larger battery for a future build.

Cheers

Aussie

G'day Martin,

I like your passion so no worries that you straying into water that was way over my head :)

After reading all your posts, and others who replied to you, I was leaning towards one larger battery, so between you and Joe's comments (above) I think the largest Mah battery with the highest C rating in 4s would be a better way to go.

I am planning on rebuilding the frame on my current hex to replace the round tube arms with square tubes as I am having issues with trims as the Tarot arms can twist in the frame causing drifting.  I will most likely incorporate a single battery set up at that time.

Thanks again for all of your wisdom and the wisdom of others who posted here.

I hope this thread can help others with the same question in the future.

Cheers

Aussie

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