# Why only this combination used? what is the advantage of this combination

#### k62524

Joined Jul 26, 2019
6
need 8 cells
but why to use 3 parallel on either side and 2 series in middle ?

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#### ericgibbs

Joined Jan 29, 2010
12,451
hi k6,
Welcome to AAC,
I think you are mis-reading the diagram, they are all in series, the two centre batteries are drawn in a simpler way.

Consider the two 2.1V cells in parallel, what would the voltage be.?

E

#### k62524

Joined Jul 26, 2019
6
hi k6,
Welcome to AAC,
I think you are mis-reading the diagram, they are all in series, the two centre batteries are drawn in a simpler way.

Consider the two 2.1V cells in parallel, what would the voltage be.?

E
Sir,
We are trying to build a battery, we are reaching a battery spec only if we are using this combination.
So i have a doubt why cant we use other combinations like all series or series at end sides.

#### ericgibbs

Joined Jan 29, 2010
12,451
hi,
As this is homework, I can only give you hints not the final answer.

A question for you, if you built a battery in that configuration, using those cells, which all had the same specification, ie: voltage and A-hr capacity, what would be the design flaw.??
E

#### k62524

Joined Jul 26, 2019
6
hi,
As this is homework, I can only give you hints not the final answer.

A question for you, if you built a battery in that configuration, using those cells, which all had the same specification, ie: voltage and A-hr capacity, what would be the design flaw.??
E
Sir, this a thermal battery.

#### LesJones

Joined Jan 8, 2017
3,127
You say that you need 8 cells but your schematic shows 14 cells. How was the question worded when it was given to you ?

Les.

#### k62524

Joined Jul 26, 2019
6
You say that you need 8 cells but your schematic shows 14 cells. How was the question worded when it was given to you ?

Les.
Sir,
My sir has given this circuit, if we use other combination of paralleling circuits we are not getting the required operating time.
So why we are using three parallel combinations on either side and 2 series combinations in between where all parallels are connected in series. So total voltage we need is 2.1*8=16.8v.
We are also generating heat inside to fire the battery.

#### Alec_t

Joined Sep 17, 2013
11,997
So why we are using three parallel combinations
Why do you want them in parallel?

#### k62524

Joined Jul 26, 2019
6

#### Alec_t

Joined Sep 17, 2013
11,997
So why are you trying to heat cells? That can be damaging to the cells; even dangerous

#### crutschow

Joined Mar 14, 2008
26,974
May be for heat generating
That makes no sense.
You say it's a thermal battery.
Does that mean it's a one-shot type of battery that only operates for a short time once it's energized?

#### Alec_t

Joined Sep 17, 2013
11,997
What has voltage got to do with thermal batteries? They store heat, not electricity. Are you trying to simulate a thermal system using an electrical analogue?

#### Uilnaydar

Joined Jan 30, 2008
118
Might be a thermal model attempt. Would love to see the actual homework/project question.

#### Alec_t

Joined Sep 17, 2013
11,997
Would love to see the actual homework/project question.