Controller current rating and Battery discharge rate

[RichardT]

Hello Experts

I am trying to source for lithium cells 18650.
There is a parameter called the max current discharge rate.
Larger capacity cells tend to have lower discharge rates and vice versa.

If my controller is rated at 13Amps max current,
does it mean i should get a cell similar max current discharge rating?

Thank you for reading.

Best regards
Richard T

 

[Ykick]

What you’re asking about is “C rate”. The ability of a cell to deliver current to a load.

A 2.5Ah cell with advertised 10C rate should be able to deliver 25A. Or, 10x the 2.5Ah capacity. Probably enough for your 13A controller load.

Now if you parallel 2 of those cells in my example, the effective rate would now be 50A. Get the idea?

Some 18650 cells are only 2C which would be 5A. You'd need at least 3P (parallel) of those to handle your 12A controller. That wouldn't leave you with much headroom and probably significantly sag under load.

btw, why all the individual threads about basically the same thing?

 

[RichardT]

What you’re asking about is “C rate”. The ability of a cell to deliver current to a load.

A 2.5Ah cell with advertised 10C rate should be able to deliver 25A. Or, 10x the 2.5Ah capacity. Probably enough for your 13A controller load.

Now if you parallel 2 of those cells in my example, the effective rate would now be 50A. Get the idea?

Some 18650 cells are only 2C which would be 5A. You'd need at least 3P (parallel) of those to handle your 12A controller. That wouldn't leave you with much headroom and probably significantly sag under load.

btw, why all the individual threads about basically the same thing?

Thanks Ykick.

I apologise if my posts seem about the same thing.
But I honestly see them as separate issues.
They are related only because they are all about ebikes and batteries. This thread is to find out what battery specification is required for my controller.

I bought 2600 mah cells (2C or 5.2A) and will make them 4P (to make 10AH) of 10 cells in series , making it 20A dischargeable, much more than 13A dischargeable.

Thanks for reading and your advice.

regards
RichardT

 

[Ykick]

You're welcome to the iggy list!