What batteries to buy - Total Noob

Flydigital

Flydigital

Member
I am buying a DJI 550 ARF kit and wanted to ask what batteries to get.
I have been given a Turnigy 420 charger already.
There are so many batteries available but haven't found a good guide to making the correct choice - what all numbers mean for different factors.

Budget for batteries is ideally under $70 initially.

It will eventually carry a go pro and more if it all goes to plan!
thanks for any advice.
 

R

rilot

Member
I use Turnigy Nano-tech 5000mAh 4S batteries on my F550. They work well.

OK, so, the big number is how much charge the batteries store, measured in mAh. The bigger the number the longer it will last but also, the higher the weight.
The number with a C after is (say 35C or 50C) is how fast the battery can discharge. This is as a multiple of the capacity. So, a 1000mAh 1C battery could discharge at 1amp. A 5000mAh 50C battery can discharge at 250amps. THe higher the number the faster it can discharge but also the higher the weight. 25C is fine for an F550.
The number with an S after it is the number of cells in series and consequently the total voltage of the battery. LiPo cells are rated at 3.7V per cell (although fully charged they are 4.1V to 4.2V), so a 3S battery would be a 11.1V battery, a 4S would be 14.8V, 6S 22.2V etc etc.

So adding it all up. If you take my batteries which are 5000mAh 35C 4S packs:
5000mAh of juice in them
Can discharge at 175amps
Are rated at 14.8V

Now, when selecting batteries for an F550 it's all a matter of weight and is up for some debate. I use 4S as I wanted to lift a craft with total weight of 2.4kg but still wanted some flight performance.
 

T

Tahoe Ed

Active Member
I like the NanoTechs as well. I am flying with 4S 4000. I personally think that 5000 is heavy if you are using a gimbal, H3-2D in my case with GoPro H3, an iOSD, the mini and a vTx, an immersion 5.8gHz at 600 mw.
 


Flydigital

Flydigital

Member
Thanks for that. very helpful but also raises some more questions!....
S rating: So there is an option for voltage. What makes you choose 3s, 4s or other. Is there a 'best option'
C rating: again not sure what discharge means in real terms.
Nano-tech vs 'normal' : I see Turnigy batteries that seem to have same spec but nano are priced about 25% higher. What's the magic in nana!?

Enjoying my learning curve and thanks again for any assistance.
 


CdA D

CdA D

Member
The Turnigy batteries are low cost and have basically no guarantee, I'm not saying that they are bad. What is your craft worth? Use a good balance charger and learn how to charge, discharge and store your batteries. I use Thunder Power Batteries and charger. They aren't cheap, but I have confidence in them. Remember they are electrical and nothing electrical can be guaranteed to work every time, but if you have a problem it's good to know if the manufacture will back them up. Choose wisely and informed!
 

D

Djin

Member
Sorry to hijack the thread (how do you start a new one?).

I am based in the Dubai and a local hobby store stocks some Dualsky 6s 10,000mah batteries. The problem is they are only rated at 12C discharge rate. What would be the issues with running one of these in an S800 for example? I suppose running two in Parallel would double the amp discharge but would running just one be a big issue?

Thanks
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Hi mate. The issue would be that the LIPO wouldn't be able to deliver the necessary current to power the S800. This could either over stress the lipos, causing damage, or the S800 could drop out of the sky. Running two in parallel wouldn't help if they were both 12C, it would only double the capacity.

I personally use 40C or above LIPOs. They tend to be better quality and you're guaranteed to be working well within their tolerances thus, hopefully, increasing their lifespan.

LIPOs are the main and only powersource keeping your investment in the air so get a good brand with good ratings.

Cool?
 

D

Djin

Member
Are you sure doubling the capacity in parallel wouldnt double the amp discharge. The first post seems to say it does. I thought 12C was too low and I don't know why they are recommending them for S800's here.

I think I will go for the Gen Ace ones which are rated at 25C and using them in parallel, unless I am wrong about the Amp discharge doubling when using them in parallel
 


D

Djin

Member
24C at 20000mah is... 480A? 6 motors with 6 40A ESC could theoretically pull 240A so I think im good right... Until one pack dies and im back down to 120A from one pack...
 

P

PeterLester

Member
A secondary benefit of having two batteries in parallel is:
If one battery fails, the alternate should be capable of enabling a safe landing (despite it suddenly carrying the parasitic weight of the other non-functional battery)!
Taking in to account that battery chemistry deteriorates with battery cycles, age and low ambient temperature one should expect major challenges with individual pack C ratings much below 35C - IMHO.

24C rating for the combined packs is too low from my perspective.
 


Gionk

Gionk

New Member
Based on experience, I also believe higher-than-necessary C rating and better quality batteries pays off. Ive been flying scale helis for years, and nothing, I mean NOTHING, has outperformed my thunderpower and flight power packs. everything else has puffed, or became very prone to imbalance or bad cells. just my opinion.
I take great care with charging, balancing, and storing... but I plan on spending a little more from now on, on packs.
 



COMike93yj

COMike93yj

Still Building!
Just out of curiosity.....

How would one run twin packs in parallel? Is there a good resource to show how to do this and the care needed to do it safely?

Thanks!

Mike :)
 


COMike93yj

COMike93yj

Still Building!
Benjamin Kenobi said:
Just a simple parallel connector will do. Use identical packs with matched specs.
Click to expand...

Thanks Ben,

I am new to this....do you purchase those connectors or do you make them yourself.....I am not certain just what the connector is.

Mike

EDIT:

I did a quick search on Youtube and found this explanation......very easy to understand!!!!!

http://www.youtube.com/watch?v=_4KPGl1NMsg

 
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