Go Down

Topic: Battery for bicopter (Read 453 times) previous topic - next topic

rossi86m

Hello!!


I am building a bicopter and right now i am using a lipo battery 11.1v and 2200mha. It seems to be too heavy and i was wonderi g if i can use a smaller one like a 1500mha or 1200mha???

I am using two brushless motors (hobbymate 2204) with two 18a ESCs

What do you think?

Thanks

TolpuddleSartre

I think you'd be better asking on a model aviation forum.

Units of battery capacity are "mAh", not "mha"

rossi86m


slipstick

Hello!!


I am building a bicopter and right now i am using a lipo battery 11.1v and 2200mha. It seems to be too heavy and i was wonderi g if i can use a smaller one like a 1500mha or 1200mha???

I am using two brushless motors (hobbymate 2204) with two 18a ESCs

What do you think?
I think for a proper answer you really need to know how much current the motors are actually using. Do you have a wattmeter to measure the current?

If not then perhaps we can assume it's less than 36A (2 x 18A). There are smaller batteries that can handle that much current. If you look for a 3S 1.1V 1500mAh with a C-rating of 30 or more that should be o.k. Even a 3S 1000mAh with C-rating 40 or more will probably work. The C-rating is important.

Of course there's a trade off...the smaller the battery capacity the shorter the flight time you'll have.

Steve

Northof49

#4
May 16, 2018, 04:37 am Last Edit: May 16, 2018, 04:40 am by Northof49
You have two issues to deal with, capacity and maximum amperage rating of the battery.  C rating was mentioned above, and that is the relationship between the mah capacity of the battery, and the maximum sustained amperage it can deliver.

A 30C battery with 1200mah capacity would be capable of delivering 1.2 x 30=36 amps for 2 minutes (less the amount you need to leave in the battery to not have it drained fully).

I would start with figuring out your maximum current draw, and do the math for both how long the battery can last at that draw, and whether the amperage drawn is within the C rating of the battery.

I only find some lipo batteries can actually deliver at their C rating without sustaining damage.  Some of the cheap ones can't, and become damaged quickly.

vinceherman

You need to provide more information.
As mentioned above, you need to determine how much current the motors draw.
If you have a watt meter, you can tell us directly.
If not, at least tell us which prop you are running.

Here is a video of the manufacturer using a watt meter and a thrust meter to demonstrate the current draw and thrust with various batteries (3s and 4s) and various props.
From the video

Gemfan 3545 BN prop pulls 5 amps per motor.
Gemfan 4045 BN prop pulls 8.5 amps per motor.

Watch the video.  There are a lot of different props they try.

Either watt meter your motors or tell us which prop you are using.  Then we can talk about battery size and flight times.


Go Up