8s Battery supplier?

[Strato]

Hi All,

I'd like to run 8s on a new heavy lift build. 8s packs are hard to come by. I'm wondering if anyone has a good source for 8s packs? Ideally I want 12,000 mah packs.

Here's what I'm building:

Skyjib X4-XL Coaxial
KDE 5215 - 330kv Motors,
KDE 55AMp ESCs with 18" Props
2 X 12,000MAH 8s lipos
Power Hungry Power Distro
A2 Flight Controller, BEC voltage stepdown
Futaba 14SG TX for Pilot, Spektrum Dx8 for Gimbal
MoVI M10
iOSD2

Any ideas would be greatly appreciated.

 

[R_Lefebvre]

8S will be hard to find, normally packs stop at 6S as most chargers can't charge higher voltage than that. So, you must use 2 4S packs in series.

 

[SleepyC]

I'd just run 6s with that set up, should have plenty of punch and efficiency.

 

[Strato]

I forgot to mention the AUW will be 19 KG.
According to the KDE specs, on 6s the 5215-330kv motors will give 1900 g of thrust at 50% throttle with 18" props. 1900*8=1520 which leaves me a little underpowered. On 8s they put out 3350 g of thrust. 3350*8=26,800. This leaves some headroom and some loss in efficiency due to the coaxial setup. I'd prefer not to run 4s packs in series, but I might do that

My charger is a Junsi iCharger 4010 Duo which will charge 8s packs.

Can anyone recommend a BEC to step down the 29.6v to the FC, LEDs, FPV cam etc.?
I was looking at this: http://www.gryphon-mall.com/product.php?id_product=59

 

[Carapau]

Have you already bought the motors? If not get the 435s and use 6s. This will give you gobs of power. Otherwise you may have to make your 8s packs by using 2x4s in Aries as mentioned before. 8s packs do exist but the largest I have seen are about 5-6AH so either way you will be having multiple packs.


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[ary]

Im using KDE 5215 330kv, KDE 55a esc, 6s, super X, 22inch wood prop and 20inch CF mark II. I got those props from fox tech. stable in high winds. Wood props perform better for heavy load

 

[Old Man]

Expensive, but MaxAmps in Washington will do 8s batteries. Might want to give them a call to see if they'll make something up with lower C ratings than their usual. We just don't need 100C+ batteries.

Ary,

Like your Vulcan frame build but you might want to consider lifting the GPS up above the top plate. Move it as far from RFI/EMI noise sources as possible.

 

[Strato]

Thanks Old Man! I will give MaxxAmps a call.

Ary, What thrust output are you getting and how many amps are you drawing with the 20" props on the 5215s??

 

[Strato]

Does anyone have experience running a copter on a 8s system? I realize it's fairly new territory...

 

[Carapau]

Be warned about MaxAmps. When they quote 100c they are talking peak C not constant C. I bought some 10Ah batteries from them last year and was puzzled as to why my MR hit low voltage warnings after less than a minute. I talked direct to Maxamps and they stated that the C rating was peak and that the constant C rating was approx 4C! The do have batteries that are up near 25C constant which is what you will need, or there abouts, so just ask before you purchase.

 

[ary]

Expensive, but MaxAmps in Washington will do 8s batteries. Might want to give them a call to see if they'll make something up with lower C ratings than their usual. We just don't need 100C+ batteries.

Ary,

Like your Vulcan frame build but you might want to consider lifting the GPS up above the top plate. Move it as far from RFI/EMI noise sources as possible.

Thx Old Man,
I did move Gps higher & far backward 10cm above rear boom arm

 

[ary]

Thanks Old Man! I will give MaxxAmps a call.

Ary, What thrust output are you getting and how many amps are you drawing with the 20" props on the 5215s??

12kg, around 55%-60% throttle with 20 CF prop.
14 kg, around 50% Throtle with 22 x 7 wood prop
I cut a little bit above props to reduce pitch
My first plan to build X8. Finaly Y6 is enough to lift 15kg. More efficient/longer flight time compare to X8 & enough spare power.
Im using 2X Gens 10000mah 25C