Accelerated test on GP cells (fan cooled )
This test started as a normal accelerated test on cells but it was thought we should be cooling the cells down.
We were graphing the results as the test proceeded and noticed the pack average, pack volts at 5 minutes and the discharge time
had fallen when we applied cooling.
This is a £ 35 (Pounds Sterling) club pack!!!
Below are graphs  of  GP 3300 cells cycled 80 times with 30 minutes between cycles
It can clearly be seen that if the pack is cooled with a fan the discharge time and average volts drop.
Delta 0.08 
Charge current 4.5 amps 
Linear charge
20 amp discharge

A/V1       Average voltage over first 5 minutes

P/V1        Pack voltage at 5 minutes

D/Time     Discharge time at 20 amps (multiply by 100 for correct time)

Cells were fan cooled between cycles 14 and cycle 34, the steep peak at cycle 22 is when the battery pack powering the fan went flat. 
It can clearly be seen that cooling the cells while charging is not beneficial and reduces discharge time and pack volts.
This is the same graph as above but with the charge capacity included. 
Charge Capacity =  Char/Capacity * 1000
The Pack match of this £35 pack improved with cycles.
The cooling in the above results was applied through the whole cycle (charge and discharge)
We will repeat the tests (staying with 30 minutes between cycles ) but arrange for the fan to cool the cells only during  charge.
Following are the results of tests with and without a fan applied during charge.
The pack has already been used for tests and has already done 80 charge and discharge cycles but had rested for 3 weeks before
the tests were started.  This probably explains the good results in the first 3 charges.
The pack did stabilise after these first 3 charges and the resulting data is interesting.
The application of the fan during charge acted like a switch on the power reading obtained during charge and the
average volts, pack volts at 5 minutes during discharge
It can be seen that the power % rating obtained during charge is directly related to the average volts and the pack volts during discharge.

Cycle #

D/CAP

TIME

AVE

PV

POWER%

MATCH%

PEAK/V

F/PEAK

F/BACK

CCAP

Power%/10

Power% *50

Fan On or Off

1

3477

625

7.28

7.03

99

95

9.28

0.00

0.08

4095

9.90

4950.00

No Fan 0.08

2

3438

618

7.30

7.05

100

95

9.15

0.00

0.08

4171

10.00

5000.00

 

3

3477

625

7.18

6.92

97

95

9.43

0.01

0.08

4332

9.70

4850.00

Fan + 0.08

4

3450

621

7.17

6.92

97

95

9.41

0.00

0.08

4195

9.70

4850.00

 

5

3438

618

7.18

6.92

98

95

9.39

0.01

0.08

4202

9.80

4900.00

 

6

3427

616

7.17

6.91

97

95

9.40

0.01

0.08

4201

9.70

4850.00

 

7

3427

616

7.17

6.92

97

95

9.40

0.01

0.08

4202

9.70

4850.00

 

8

3416

614

7.16

6.91

97

95

9.41

0.01

0.08

4177

9.70

4850.00

 

9

3416

614

7.16

6.90

97

95

9.42

0.01

0.08

4170

9.70

4850.00

 

10

3427

616

7.27

7.02

100

95

9.22

0.00

0.08

4052

10.00

5000.00

No Fan 0.08

11

3416

614

7.29

7.04

101

95

9.12

0.00

0.08

4158

10.10

5050.00

 

12

3416

614

7.28

7.03

101

95

9.13

0.01

0.08

4177

10.10

5050.00

 

13

3416

614

7.28

7.03

101

95

9.13

0.00

0.08

4176

10.10

5050.00

 

14

3411

613

7.28

7.03

100

95

9.15

0.00

0.08

4158

10.00

5000.00

 

15

3433

617

7.14

6.88

97

95

9.46

0.00

0.08

4282

9.70

4850.00

Fan 0.08

16

3411

613

7.15

6.89

97

95

9.42

0.01

0.08

4139

9.70

4850.00

 

17

3400

612

7.16

6.90

97

95

9.41

0.01

0.08

4146

9.70

4850.00

 

18

3388

609

7.14

6.89

97

95

9.43

0.01

0.08

4145

9.70

4850.00

 

19

3400

612

7.16

6.90

97

95

9.41

0.01

0.08

4121

9.70

4850.00

 

20

3416

614

7.19

6.92

97

95

9.40

0.01

0.12

4257

9.70

4850.00

Fan + 0.12

21

3422

615

7.20

6.93

98

95

9.39

0.01

0.12

4257

9.80

4900.00

 

22

3422

615

7.19

6.93

98

95

9.39

0.01

0.12

4270

9.80

4900.00

 

23

3422

615

7.20

6.92

98

95

9.38

0.01

0.12

4282

9.80

4900.00

 

24

3377

607

7.28

7.03

101

95

9.11

0.01

0.12

4108

10.10

5050.00

No Fan 0.12

25

3394

610

7.29

7.04

101

95

9.09

0.00

0.12

4232

10.10

5050.00

 

26

3400

612

7.29

7.04

101

95

9.11

0.01

0.12

4239

10.10

5050.00

 

27

3400

612

7.29

7.03

101

95

9.11

0.01

0.12

4245

10.10

5050.00

 

28

3394

610

7.28

7.03

101

95

9.13

0.00

0.12

4227

10.10

5050.00

 

29

3388

609

7.29

7.03

101

95

9.12

0.01

0.12

4233

10.10

5050.00

 

30

3383

608

7.29

7.03

101

95

9.12

0.00

0.12

4232

10.10

5050.00

 

 

It can be seen that the Power% reading obtained during charge, the Average volts and Pack volts at 5 minutes obtained during discharge
are adversely affected by the use of the fan during charge.
Increasing the delta fallback from 0.08 to 0.12 at cycle 20 did improve the readings, but not as much as removing the fan at cycle 24.
To help with interpreting the results we have indicated the condition of the fan on the graph.

Fan Off  = 8.00

Fan On = 9.00
Although the fall in volts is small at 0.12 volts but  this is at 20 amp discharge, it could be 0.6 volts at 100 amps.
The following graph is the effect of the fan on the  charge and discharge capacity.
There does not seem to be a great effect on the discharge capacity apart from a slight fall, but this is probably because of the number of cycles.
The charge capacity appears quite stable apart from the peaks and troughs when the cycle changes from fan use to no fan use!!!
Fan Off  = 3500
Fan On = 4000