hello there im new to this website
i have built 50 inch wings span twin cargo plane with use of racerstar 2700kv and 30a esc
and vie use 5 inch of props is props are good ??
but anyway my question is there is too many cheap 18650 cell out there and i want to know from winch cell i can make big mah and high amp rate batter for longer flight time
THnQ

I would recommend any cheap 18650 cells if it is going to power your tx because it only needs 100mA of current which most 18650 will be able to supply.
But for planes or any build which have high current draw you have to check the cells datasheet. Generally panasonic, samsung, LG are manufacturers and not all 18650 are same. The model number will be present on 18650 cells which you can use to check the datasheet.
Lets say suppose your current draw is 30A peak then you need the battery which will provide that. If a model is capable of providing the same or more then you can go ahead. If not you may need to connect couple of packs in parallel to provide adequate power.

Quote from: ARROWRC on July 24, 2018, 11:01:48 AM
hello there im new to this website
i have built 50 inch wings span twin cargo plane with use of racerstar 2700kv and 30a esc
and vie use 5 inch of props is props are good ??
but anyway my question is there is too many cheap 18650 cell out there and i want to know from winch cell i can make big mah and high amp rate batter for longer flight time
THnQ

I'm replying assuming that you are new to this hobby. If not, please ignore my comments/suggestions

There are two issues involved. Suitability of battery, and suitability of model.

1. Battery
I see that robu.in has a 2200mah 3.7v for Rs 199. You'll have to put 3 in series.
This means a battery box or soldering. Both unreliable for RC airplane use.
More importantly, C rating is not mentioned. If you draw 2amps, it may last for an hour.
But can it give 10, 20 or more amps? One doesn't know.
Incidentally in the last 4-5 years I don't recall any member using Li Ion to power an RC airplane.
The most commonly used are 3s Lipos of 2200mah and 20-30C rating, about 180-200gms.
Or 3s 1000mah Lipo of 20-30 C rating, about 80-90 gms.
So please consider using what is known to work, to reduce imponderables/ increase reliability.

2. In case you are new to RC flying, a twin engined cargo plane is hardly the best choice to learn on.

Welcome to this forum.
Please post pics of your model. That will get you more responses.
Regards

@arrowrc,
Oops.
Saw your other posts.
Made my reply here irrelevant.
So pl ignore...
Regards