10S4P with Lithium ion battery; Question on the calculation

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Discussion Overview

The discussion revolves around the configuration and calculations related to a 10S4P lithium-ion battery pack using Panasonic NCR-18650 cells for a battery electric vehicle (BEV). Participants explore the implications of series and parallel connections on voltage, capacity, and energy density, while also addressing safety concerns associated with high voltage and current systems.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant calculates that a 10S configuration yields 36 V and 10.44 Wh, and questions the discrepancy with the claimed 417 Wh for the 10S4P configuration.
  • Another participant points out that the watt-hour value should increase with the number of parallel cells, implying a misunderstanding in the initial calculation.
  • A participant expresses interest in motorizing a recumbent trike and mentions plans to document the build in another forum.
  • Further inquiry is made into the differences between a 10S4P configuration and a 40P configuration, highlighting the voltage and capacity differences between the two setups.
  • Concerns are raised about the dangers associated with high voltage and current, suggesting the need for expert guidance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the calculations related to the energy capacity of the battery configurations, and there are differing views on the implications of the configurations regarding safety and performance.

Contextual Notes

Participants express uncertainty regarding the calculations of energy capacity and the implications of different battery configurations. There is also a lack of clarity on the definitions and effects of series versus parallel connections in this context.

Who May Find This Useful

Individuals interested in battery configurations for electric vehicles, those exploring lithium-ion technology, and participants in discussions about energy density and safety in high-voltage systems may find this discussion relevant.

marellasunny
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I am planning to use the Panasonic NCR-18650 cylindrical cells for a BEV (Battery Electrical Vehicle). As it would be easier to buy ready-made modules, I have found a supplier selling a Li-ion pack that delivers 417 Wh(or in other words 11.6 Ah) at 36 V (something like what this guy uses... http://www.electricbicycleworld.com/36V-11-6Ah-Lithium-Ion-Frame-Bottle-Mount-p/hx-bb-11.6ah-36v.htm ). Upon further inquiry, he says its a 10S4P i.e 10 in series and 4 "strings"(whatever that means) in parellel.

The Voltage and Energy density calculation part is where I get confused:

The panasonic datasheet says that each individual cell has 10.44 Wh of energy and supplies it at 3.6 V.
So,

10 cells in Series → 36 V and 10.44 Wh

IF I arrange these cells in 4 "parallel" rows, I get → 36 V and 41.76 Wh. But, the guy claims 10S4P supplies 417Wh. Where am I going wrong?
 
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marellasunny said:
10 cells in Series → 36 V and 10.44 Wh

Where am I going wrong?

You are keeping the same watt/hr value despite the increase in number of cells.

P=IE
 
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BTW I have an old tadpole recumbent trike I have thought about motorizing as well. I would enjoy watching your progress as you build.
 
montoyas7940 said:
BTW I have an old tadpole recumbent trike I have thought about motorizing as well. I would enjoy watching your progress as you build.

My build will be from time-to-time be posted in the Automotive engineering forums in Physics forums. I would love to document and share the information online but unfortunately my contract blocks me from doing so. Neverthess...you'll find me in the AE forum :).

Last question:

What is the difference between connecting the cells in a 10S4P format('TEN' 18650 cells in Series arranged in 4 columns connected in parallel) as compared to connecting the cells in a 40P (all 40 cells in parallel) ?

10S4P-pack gives me 36 V and 417 Wh and 11.6 Ah.

40P-pack on the other hand gives me 3.6 V and 417 Wh and 116 Ah. ( like this pack here...http://www.kreiselelectric.com/en/technology/battery-system/battery-pack/ )

My Brusa HSM1-10.18.13 motor has a specfication of 360 V - 400 V and max RMS current of 300A.
 
marellasunny said:
Last question:

What is the difference between connecting the cells in a 10S4P format('TEN' 18650 cells in Series arranged in 4 columns connected in parallel) as compared to connecting the cells in a 40P (all 40 cells in parallel) ?

10S4P-pack gives me 36 V and 417 Wh and 11.6 Ah.

40P-pack on the other hand gives me 3.6 V and 417 Wh and 116 Ah. ( like this pack here...http://www.kreiselelectric.com/en/technology/battery-system/battery-pack/ )

My Brusa HSM1-10.18.13 motor has a specfication of 360 V - 400 V and max RMS current of 300A.

I'm not sure what you are asking regarding the difference. But the voltage and current you are considering can be very dangerous. You need an expert.
 

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