How do I choose which battery is the best for my application

[marine7]

Hi there,
Im building a pack for electric trolling motor and I would like to know what would be the best option for me.( or the safe discharge rate, so I don't heat the pack or over discharge it with the loads?


The motor use 15A in continuous in full speed, with peak up to 18 max.

so each cell have 10A max discharge rate, would that mean in each series is 10A * 14in Parallel =140A does that mean the pack is capable of drawing 140A ( so my 15a is very low)
The pack will be 7s14p 24v 49000mah

I've been looking at LG MJ1 10A = 3500mAh
AND M36 10A = 3600mAh

Many thanks

 

[flat tire]

Yes.

 

[spinningmagnets]

The cells in series determine the voltage.

The parallel count determines the capacity of run-time, plus the total amps. If you use a 3500-mAh cell that is rated for 10A, and you need 20A peak, then 2P will provide 20A peak. The capacity of 3500-mAh cells in 2P will be 7.0-Ah, which is not much.

Of course this is just the minimum, I would always recommend the biggest pack you can fit, and can afford.

 

[electric_nz]

sounds like a dream life for any cell, at 15A draw divided by 14p you will only be drawing less than an amp per cell. if you limit the charge and discharge to 90% and 20% you should get good cycle life.

suggest reading the thread on Li-ion battery aging, some of the testing suggests 1000 charge cycles is within reach.

 

[hemo]

I think the Op has done so by the choice of the two cells he is thinking of .

 

[marine7]

Thanks Guys,

the m36 has low A discharge up to 5A but 1000 Cycles.
While mj1 have high A discharge rate up to 10A but 400 Cycles.

 

[flat tire]

You want the one with high cycle life since your 14p * 5a will give plenty of overhead to a motor you plan to run at 15 amps most of the time.