Battery choice... Need help!

[KillerDave]

Hi Folks,

I am building a HK H-800 Hex and need advice on battery choice...
This is my first real build and I';m learning quite fast but just need a little push in the right direction....

Ok, here';s my set-up so far....

Motors - http://rctimer.com/product-509.html
ESC';s - http://rctimer.com/product-1067.html
Prop';s - http://www.amazon.co.uk/gp/product/B...ilpage_o01_s00

I and running a Pixhawk and 3DR telemetry

I also have retractable landing gear and a GoPro mounted on rails as is the battery tray to help with CofG...

So, I do have Turnigy 5s 5000mAh Nano Tech';s but I';m not sure they are the best choice???

I have been looking at the Multistar batteries but also not sure on the size and capacity that would be best for my set-up???
Plus, they';re NEVER in stock!!!???

Can anyone advise please?

[Revs]

The link to your props isn';t working but I assume they';re 12x4.5" ish..?

I';d say a 8000mAh 4s Multistar would be good, as long as you';re hovering/slow flying and not blasting about too aggressively. If you';re wanting to give it some stick I';d go for 5000-6000mAh 4s with a 25c minimum rating.

[KillerDave]

The link to your props isn';t working but I assume they';re 12x4.5" ish..?

I';d say a 8000mAh 4s Multistar would be good, as long as you';re hovering/slow flying and not blasting about too aggressively. If you';re wanting to give it some stick I';d go for 5000-6000mAh 4s with a 25c minimum rating.

Hi Revs,

Thanks for the reply! The prop';s are 13 x 6.5... maybe I should go a little smaller???

Here';s the link again....

http://www.amazon.co.uk/gp/product/B00OLOZ8VC?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00

The thing with the Multistars is that they are never is stock! Lol....

I just weighed the rig and it comes in at 3kg without a battery.... Will that be an issue?

[KillerDave]

Hi my hovering friends...

Still coming up short on Multistars and wanting to have "headroom" onmy packs, I have these in line...

http://radiocontrolledshop.ie/4s-148volts-li-po-battery-lithium-polymer-rc-batteries/6779-giant-power-4s-6600mah-25c-lipo-battery-lc-4s6600ea.html

Can I have a yay or neigh on these? They are at least in stock! 

[Revs]

I';d be more inclined to get something like.. http://www.hobbyking.co.uk/hobbyking/store/uh_viewItem.asp?idProduct=73432

Much cheaper, very high ';C'; rating, only slightly smaller and 230g lighter! Plus ZC';s are highly regarded.

[KillerDave]

I';d be more inclined to get something like.. http://www.hobbyking.co.uk/hobbyking/store/uh_viewItem.asp?idProduct=73432

Much cheaper, very high ';C'; rating, only slightly smaller and 230g lighter! Plus ZC';s are highly regarded.

Only 3s???

TBH, I';ve never looked at Zippy';s....

What about this one....

http://www.hobbyking.co.uk/hobbyking/store/__63431__ZIPPY_Compact_6200mAh_4s_40c_Lipo_Pack.html

[Revs]

Thought I must have been missing something there. The one you linked to is good

[Chippercheese]

Only 3s???

TBH, I';ve never looked at Zippy';s....

What about this one....

http://www.hobbyking.co.uk/hobbyking/store/__63431__ZIPPY_Compact_6200mAh_4s_40c_Lipo_Pack.html

I use some zippy compact 4S 4000mAh - can';t fault them at all.

[KillerDave]

What rigs are you all flying? and LiPo spec';s???

[Pork Chop]

Where battery packs are concerned, the laws of diminishing returns apply!  That is, perhaps you can fly with a massive 16,000 mAh pack weighing-in at almost 2Kg, but the motors have to work so much harder, drawing a lot more current and have you wondering why you don';t get the flight times you might have expected.  There';s a sweet spot for every set-up and that';s all about balancing your desired flight times against weight, C-rating and of course, voltage.

I';ve been flying fixed-wing electric for many years and where possible I will always go for the lowest C-rating and lowest weight, preferring to connect two packs in parallel rather than use a ';big brick';.  For example, on my F550 I used 2 x 4000mAh, 4S Multistar packs* which gives me 8000mAh and 20C for a weight of a tad over 600g.  On the other hand, I have a Turnigy 5000mAh ';brick'; which alone weighs 630g but gives me a C-rating of 35-45 amp and frankly, if I ever draw that much current (~200A), I will have melted all my cables and ESCs so it';s essentially wasted ';capacity'; which serves only to add weight for zero performance benefit.  Actually, in testing, I get no longer flights with the 5000mAh pack than I do with a single 4000mAh at half the weight, in fact, I would say the 4000mAh pack gives me slightly longer in the air.   Also, if you find you';re only flying for about 10 minutes at a time, why bother fitting a humongous pack that could keep you in the air for 20?

There are other benefits of running two packs in parallel, for example, it may offer a degree of redundancy and if you notice one pack is not charging as you expect or going ';soft'; or ';puffy'; you only need to replace one pack and not bin a single bigger-money battery.

The moral of the story is don';t always go for big-C and larger capacity is not always better!  Figure-out the weight vs performance sweet spot for your specific rig - but remember, in clean air your craft will be much more efficient than in gusty, windy and maybe turbulent conditions.

That';s my take on things and it works for me.

* This set-up gives me a safe 16 minutes in the air and are just nicely warm on landing

[Panther]

Personally I have had no luck with the compacts and the plain old Zippy Flightmax gives me less trouble.
In comparison there is very little difference, if any, in size between a Zippy compact and a Zippy Flightmax.

[KillerDave]

Personally I have had no luck with the compacts and the plain old Zippy Flightmax gives me less trouble.
In comparison there is very little difference, if any, in size between a Zippy compact and a Zippy Flightmax.

Aghh! I placed the order already!....
I think its the best shot I have so far so i';ll see how it goes...

I';ll update when it';s all together and flying....

I also have to fix the landing gear!