Hello,

I have a  5 inch quad running INAV , configured to do missions and other navigation features.
It weighs 410gm without lipo.
load current of motor as per spec is 19.2A and total draw of 4 motors around 80A. Motors are Racerstar BR2205 2300KV

I have been flying a Tattu 3300mah 3s 35C lipo weighing 260gm for last several months. And was getting around 10 mins flight time.
On last flight, quad got crashed and lipo got damaged.

I am now looking for a new lipo
I was thinking, I will go for a smaller capacity 2200mah lipo which will be around 180gm (saving 80gm on AUW). Can I still expect same amount fight time? Or should I go for heavier 3300mah itself?

Being in India, the selection of lipos to choose from are very less. I have identified below brands,

Bonka 2200mAh 35C 3S  175gm
Wolfpack 2200mah 25c 3S 180gm
GIGA 2200mah 35C 3S 180gm

Tattu with smaller capacity is not currently available.
I have heard of only Bonka brand from above. It seems rest are imported from China and branded locally.
please help me choose. 


Thanks.

If it’s not acrobatic maybe look into using LI-ion batteries they have higher capacity to weight ratio than Lipod

(23-Dec-2018, 01:15 PM)Oscar Wrote: If it’s not acrobatic maybe look into using LI-ion batteries they have higher capacity to weight ratio than Lipod

Li-ion availability is an issue.

It is hard to say where the tipping point is, where the weight of the lipo actually give you decrease flight time. I can tell you that my 1800mah packs 4S, when I fly at cruising speed, I can get around 8 minutes on a 5 inch. I land when my cells get to around 3.4V. Your quad does weight more than mine.

You can try to use ecalc to figure out your flight time. Most people find it very close to the real world.

As for brand, other than Bonka, I have not heard the others. And even Bonka are not usually recommended lipos. Like Oscar say, go with Li-ion. I can't imagine availability is so limited on 18650 li-ion, considering that so many things use these battery. You understand that you will have to build your own pack.

Laptop batteries usually have three to six 18650 (sometimes larger) cells and a protection PCB as well for charging.

(23-Dec-2018, 04:01 PM)voodoo614 Wrote: It is hard to say where the tipping point is, where the weight of the lipo actually give you decrease flight time.  I can tell you that my 1800mah packs 4S, when I fly at cruising speed, I can get around 8 minutes on a 5 inch.  I land when my cells get to around 3.4V.  Your quad does weight more than mine.

You can try to use ecalc to figure out your flight time.  Most people find it very close to the real world.

As for brand, other than Bonka, I have not heard the others.  And even Bonka are not usually recommended lipos.  Like Oscar say, go with Li-ion.  I can't imagine availability is so limited on 18650 li-ion, considering that so many things use these battery.  You understand that you will have to build your own pack.

Is yours an INAV quad with GPS? Just curious to see your setup.
Are you referring to something like this? LITHIUM-ION 18650 RECHARGEABLE CELL 3.7V 2200MAH (2C) GRADE-A
So if I connect 3 of such in series, I get a 2200mah 3S pack? They weigh 41gm each

connecting the three in series with give you an 11.1 volt nom, 2200mah LION pack. I have a few home-made two cell (7.4vdc) used for powering bike lights. Used 2100mah cells from a laptop and they work fine. I am charging cells independently with a NiteCore 4 circuit LION charger, so the lack of cutout PCB is not really an issue.

My motors maximum current draw is 80A. Assuming I fly at 50% throttle, I would need 40A.
18650 cell I found have a "Maximum Discharge Current" of 5.2A

How can it provide sufficient power to the motors?

I don't have an iNav setup. Just a basic freestyle setup. Anyway, here is a build that uses Li-ion pack. His video are great.

https://rotorbuilds.com/build/13379

I dont have a INAV, but you can choose from these battery: ( you can find all of them on ampow.com)
gens ace 2200 3s (184g）
ovonic 2200 3s with xt60 plug (168g)
Ovonic 3000 3s (193g)

(26-Dec-2018, 04:18 AM)rcxlfjne Wrote: I dont have a INAV, but you can choose from these battery: ( you can find all of them on ampow.com)
gens ace 2200 3s (184g）
ovonic 2200 3s with xt60 plug (168g)
Ovonic 3000 3s (193g)

Thank you. Due to restriction on importing lipo, I can only buy from India based website.
I am still evaluating li-ion custom pack option. Sony 18650 vtc6 is the only battery I found which can provide 20A discharge and it is not little expensive. So cost will go little above lipo. But I may be able to reduce weight by some 30 to 40g.

A friend of mine starting a new venture to build li-ion packs out of 18650 cell with some built in fuse.
He claims his 3000mAh 3s packs weighing around 160gm can produce 20A/40A discharge.
I am still evaluating my hover current draw.
If its within the limit, I will attempt his new pack.