Advice on Li-Ion battery to power A2122 Brushless Motor

Hello, I want to build a vacuum cleaner for a CNC machine with the A2122 1400KV motor
Max. efficiency: 80%
Max. efficiency current: 4-10A ( more than 75%)
Current capacity: 12A/60s
No Load current @ 10V: 0.5A
No. of cells: 2-3 Li-Poly

I found options for Li-Ion battery with diff current ratings, hope to receive advice on which is better for my vacuum cleaner project

18650 Lithium 3.7V Rechargeable Battery 1800mah 2200mah 2600mah 3000mAh

You need to check the CURRENT ratings. The mAh numbers you posted are CAPACITY not current. Provide links to the actual batteries you're considering then we can advise.



This is the product I'm considering right now.

That doesn't have a current rating though...

For LiPo/LiIon batteries its common to give the maximum discharge current by a C-rating (just to be confusing!). If a cell is rated at 3C for instance, this means it can go upto 3 times the ampere hour rating as a current - so for instance 1.5Ah (sometimes shown as 1500mAh) with a 3C rating is good upto 3 x 1.5 = 4.5A current drain).

Another way to think of C ratings is as how quickly it can be discharged. 3C can discharge in 1/3rd of an hour (20 minutes), 10C in 1/10th of an hour (6 minutes).

You should probably be conservative with these ratings for enhanced safety and battery life, note. So if you want 10A with a 3Ah battery, 3.3C would be enough just, but 5C or 10C would be much better choices for the current rating (15 and 30A respectively).

And the elephant in the room is that some lithium batteries come with a protection circuit built in and some without - its important to use protection with all lithium rechargable cells/batteries, which can be internal to the battery or external.

Battery How about this one? Its protected
:white_check_mark: Model: NCR18650GA
:white_check_mark: Size: 18650
:white_check_mark: Style: Flat Top/Button Top
:white_check_mark: Chemistry: NCR
:white_check_mark: Nominal Capacity: 3800mAh
:white_check_mark: Continuous Discharge Rating: 10A
:white_check_mark: Nominal Voltage: 3.7v
:white_check_mark: Protected: Yes
:white_check_mark: Rechargeable: Yes
:white_check_mark: Approximate Dimensions: 18.5mm x 65.3mm
:white_check_mark: Approximate Weight: 48g
Nominal voltage: 3.7V (4.2V after fully charged, discharge cut-off voltage 3V)
Internal resistance: the battery is less than 80mΩ

Sounds plausible - the continuous current rating is enough if the fan motor isn't being pushed beyond its ratings. This means choosing a matching fan that loads it correctly.

I'm trying to do similar thing. Brushless motor + 18650.
But what I'm trying to make is a long battery life min boat. It doesn't need to be very fast but it has to last for 6+ hours, and to withstand 25-30 knots of wind.

Anyone know any reference info on the electronic components and design for controlling Brushless motor + 18650?

What brushless motor and what 18650s? And what does wind have to do with it? Wind doesn't usually affect batteries or motors. I think you need to say a lot more about what you are actually trying to do.


in windy and wavy conditions, the motor needs to be more powerful to move forward against the wind, waves or even sea current.

at the moment, I don't have any specific model in mind. I'm gonna try by guessing first to find out how much thrust I need in different conditions.

Indeed, but without the actual figures there's absolutely nothing to go on. How much power is needed? Do you have any estimate or measurement of that?

BTW you should have started you own thread, not hijacked one, as this will cause confusion to people answering.

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