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
Replies
beware, if one of the batteries has a voltage drop, you are dead while in parallel not.
So be shure to use fresh and good quality batteries.
Always stay far from voltage limit of the battery.
Amperage draw correspond to the battery lowest Ampère rating , it will not add as for parallel.
So in series, if a battery as 3A and the other has 10A , you will have a 3A system.
Personally my experience is "lower cost" multiple batteries in series/parallel has two fold benefit. If a cell in a pack goes bad, your only out 1/2 the pack (unless you know how to assemble packs with a simple spot welding technique, 99% don't). I have used the Turnigy hardcase 4S-5000 packs (at $21/ea on sale shipped) for my AP 600mm deadcat quad and electric bikes for years now (I buy them for her bike, but mostly get used for my quad, lol), I have not found a better bang for buck yet, if you find something please post, tia.
Here is the pack I get for $21 shipped when on sale
http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4...
Thanks for your replay Alasdair,
I am using Zippy 30C 5000mah High Discharge "Flightmax" LiPo batteries. I use 2 at a time and get about 13 to 14 minutes before I hit 13.7v (my personal get the hell home voltage)
Maybe that is a good time and I am just being greedy wanting more? I still think, from the comments here and my gut feeling, that 2 is better than one larger battery.
Zippy do have an 8000mah 30c. Two of those might get me the extra I need.
Cheers
Aussie
What is the weight of your copter ?
What props are you using ?
Without this information it is hard to help you to increase flightime.
A quad with average efficiency and no payload will fly 60 minutes with one 5000 mah 4S battery while only 69 minutes with two 5000mah 4s batteries.
Spot on
The 4 x 2500mAh batteries combined will have a lower internal resistance than the 10000mAh battery and so will produce a much lower volt drop across the battery, Each battery will also be supplying 1/4 of the total current and so they will be less stressed and last longer.
With the lower volt drop the measured voltage at the power module will be higher and so the aircraft will fly for longer before you reach the lower limit.
It is also a safety feature as one battery failing will not bring down the aircraft. on a side note this also causes less structural damage in the event of a sudden arrival. the batteries can be secured individually and some may not detach.
Been doing this for a long time. never had a problem with this at all.
Thanks mate for your input. As per my response above, I am currently using 2 x 5A 4s batteries. My Hex is a bit crowded for 4 x 2.5's so I think, after reading all you guys' comments, I will stay with 2 x 5A vs 1 larger. Maybe upgrade to 2 x 6A :) if the weight isn't to much different.
Cheers
Aussie
Hi,
do you mean 1 larger 4s 1p battery or 4s 2p battery
2p is more complicated since balancer doesn't work for parallel connected cells.
If you prefer 2 x smaller batteries you need your charger equipped with 2 balancers
or charge your batteries one after the another.
Personally, I prefer 1 larger battery, so the Apple and other manufacturers of smartphones, tablets, laptops.
What is the weight of your hex ?
How much Watt / Ampere do you need to hover ?
(They will have the same max amps draw when you parallel the 5000's)
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