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LG MJ1 3500 mAh Max current confusion  

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cellmate
(@cellmate)
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Joined:5 months  ago
Posts: 1
15/11/2018 8:00 pm  

Hi all,

The LG MJ1 3500 mAh cells are listed on the store at supporting a 10a continuous discharge. Several other online stores say the same.

However, the linked spec sheet from LG states that 10a is the MAX current draw, with 4A continuous quoted as the "high drain" scenario under which 80% capacity remains after 400 cycles.

So  can these cells actually handle regular, sustained 10a draw? If so  what kind of lifespan can I expect? 


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Micah (Vruzend Rep)
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Street cred = 5 Ah Admin
Joined:2 years  ago
Posts: 472
26/11/2018 9:59 pm  

All 18650 manufacturers tend to rate their cells at the very limits of their abilities, so it is usually recommended not to push the cells to the manufacturer's limit often. That being said, LG MJ1 cells are rated by LG to sustain 10A continuous discharge. However, when they do cycle testing, they always discharge at lower rates to get better life cycle ratings (all companies, such as Panasonic and Samsung, also do this). I don't have data on what the cell cycles would be if you always discharged at 10A continuous, but I'd guess it'd be closer to 300 cycles than 400, give or take. But as far as I know, the manufacturer has not provided hard data on that use scenario.


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jim oneill
(@jim-oneill)
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Posts: 1
13/12/2018 9:45 am  

Micah,

Im building a battery pack with these cells lghg2.My pack will be in a 8s4p configuration. the scooter had qty 2 12v50ah gell type lead acid batteries in series to power an 900 watt electric motor.Do you think this would be enough? I calculated that the motor would draw a current at full throttle of  +\- 32 amp. Your opinion would be appreceated, and by the way thanks for your help in getting the v2 building kit.


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Micah (Vruzend Rep)
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Posts: 472
17/12/2018 5:41 pm  

Hi Jim,

That should be alright for those cells. They'll run a bit warm but that should be within their spec.


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alprine
(@alprine)
Street cred = 10 mAh
Joined:2 months  ago
Posts: 5
13/02/2019 7:13 pm  

I am looking at buying some 18650 batteries that are rated at 4000mah. I have heard that these are exaggerated numbers. Should I be concerned about these batteries? These are not coming from China. I have heard the batteries coming from China are miss leading about the rating.


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Micah (Vruzend Rep)
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Street cred = 5 Ah Admin
Joined:2 years  ago
Posts: 472
19/02/2019 9:37 am  
Posted by: alprine

I am looking at buying some 18650 batteries that are rated at 4000mah. I have heard that these are exaggerated numbers. Should I be concerned about these batteries? These are not coming from China. I have heard the batteries coming from China are miss leading about the rating.

Yes, as of right now I am not aware of any 18650s with more than 3500 mAh ratings. And even those give a true value of closer to 3,300 mAh or 3,350 mAh under higher real world loads.


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alprine
(@alprine)
Street cred = 10 mAh
Joined:2 months  ago
Posts: 5
20/02/2019 7:11 pm  

Thanks. I just ordered 400 3000mAh 3.7 volt 18650s. I have a 60 amp MPPT charge controller coming with 4-100 amp solar panels. With the charge controller I have heard I don't need a BMS. Is this true?


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