1  INTRODUCTION 

ETRS was contracted by Battery Equaliser Australia (BEA) to evaluate performance of an additive for lead-acid batteries. The Battery Equaliser (BE) additive is claimed to improve the performance of lead-acid batteries which are exhibiting some degree of capacity loss associated with an aging process referred to as "sulphation". The product is not marked as a "cure-all" and clearly will not improve the performance of "dead" batteries resulting from mechanical damage to lead and lead alloy grids, commoning bars and cell interconnects. Similarly, capacity losses caused by overcharging cannot be recovered.

In preliminary discussions, BEA outlined the scope of testing to date. The product had been successfully trialled in fork-lift batteries which showed evidence of significant capacity loss. Performance was based on hours of operation before recharge and it is claimed that capacity improvement was generally significant and warranted investment in a scientifically controlled research program.

ETRS was requested to submit a test program proposal and program budget to BEA for consideration. This was undertaken and approved by BEA. ETRS were instructed to proceed with the testing on 13th April 1997.

2  SCOPE of WORK

 The agreed scope of work involved the following items:

• Set-up of battery test circuits in controlled environment test laboratory.
• Purchase of ex-Govt 6V 105Ah Telecom type pasted plate Pb-acid stationary batteries.
• Charge-discharge (10h-rate) conditioning cycling of batteries to establish performance characteristics and to achieve stable capacity.
• Compare battery performance before and after Battery Equaliser (BE) addition with respect to cell voltage and positive and negative plate voltage characteristics during charge and discharge.

3  TESTING METHODOLOGY

 The testing program was designed to achieve a stable performance in the individual battery cells before the Battery Equaliser (BE) product was added to the cells. The cells were then subjected to a series of 10h-rate discharge/charge cycles to establish the effect of the BE additive on performance. In addition to cell voltage, the positive and negative plate potentials were also monitored throughout selected discharge and charge cycles.

A 3h-rate discharge was superimposed on the 10h-rate discharge 2 hours and 7 hours after the start of discharge. The 3h-rate was maintained for 10min which enabled additional information to be obtained on the effect of the BE additive on cell performance characteristics.

ETRS was advised by BEA to treat selected cells with 50ml of BE additive and to subject the cells to a series of discharge/charge cycles and monitor the response in terms of cell capacity improvement and identify any other detectable changes in battery performance characteristics.

4  TEST RESULTS

4.1  Battery Conditioning

The cells achieved stable capacity values after three preliminary 10h-rate discharge cycles, eight 3h-rate discharge cycles and three final 10h-rate cycles. Battery discharge capacity was found to be controlled by the positive plate capacity in some cells and the negative plate capacity in others. This is determined by the degree of negative and positive plate potential polarization at the end of discharge.

Note:  It is believed that this type of cell is constructed  with excess negative plate capacity to offset deterioration caused by aging. If this is the case, the negative plate limited cells are likely to have aged more than the positive plate limited cells. However, on the basis of the 10h-rate capacity figures after the preliminary discharge/charge cycles the cells were operating close to the nominal rated capacity.

^{On charge, there was good voltage differentiation between the PbSO₄/Pb reaction and the H₂ reaction on the negative plates in all the cells. Typically, the voltage differentiation between the PbSO₄/PbO₂ reaction and the O₂ evolution reaction on the positive plates was less pronounced. The maximum cell potential varied between 2650 and 2870 mV. This was a result of differences in both the negative and positive plate maximum charge potentials.}

4.2  Battery Equaliser Addition

The capacity results obtained before and after treatment with the Battery Equaliser additive are discussed below and summarized in Table 1. 

Battery A: 

Successive 10h-rate discharge curves for Battery A are shown in Figs 1 and 2 to demonstrate the reproducibility of the test. Figs 3 and 4 show the characteristics of the positive and negative plates during the second of the two discharge cycles. The sharp decrease and recovery in potential at 2h (and 2.7h) and 7h is produced by the higher current 3h-rate discharge superimposed over the 10h-rate discharge. The corresponding curves are shown in Fig 5.

The cells in Battery A showed the following similarities and differences in discharge characteristics after the conditioning cycles and prior to the BE addition:

• The cell potentials were very similar during the first half of the discharge cycle.
• Cells 2 and 3 had very similar capacities which were 6% higher than Cell 1.
• Cells 1 and 2 were positive plate limited whilst Cell 3 was negative plate limited.
• The -ve plates exhibited a higher degree of polarization than the +ve plates at the 3h-rate
  
• The degree of polarization was more pronounced towards the end of discharge (7h). 

The cells in Battery A showed the following differences in charge characteristics at this stage of testing:

• Cells 1 and 2 exhibited identical charge characteristics until the cell potential reached 2450mV.
• Cell 2 achieved a higher potential of 2800mV at the completion of the charge cycle compared to 2675mV for Cell 3.

After addition of 50ml of the Battery Equaliser Additive to Cell 1 and subjecting the battery to three 3h-rate discharge cycles and one 10h-rate discharge cycle, no changes were detected in the above cell performance characteristics.

Battery B:

The 10h-rate discharge curves for Battery B after the conditioning cycles are shown in Figs 6-8 together with the discharge characteristics of the positive and negative plates during discharge. The crresponding charge curves are shown in Fig 9.

The cells in Battery B showed the following differences in discharge characteristics at this stage of testing:

• Cells 2 and 3 followed very similar discharge curves through 70% of the discharged cycle but the negative plate capacity was greater in Cell 2 which extended the discharge life.
• There was a 6% capacity difference between the three cells (Cell 2>Cell 3>Cell 1).
• Cells 2 and 3 were positive plate limited whilst Cell 1 was negative plate limited.
• The -ve plates exhibited a higher degree of polarization than the +ve plates at the 3h-rate.
  

The cells in Battery A showed the following differences in charge characteristics at this stage of testing:

•  Cells 1 and 3 exhibited almost identical charge characteristics.
• Cell 2 achieved a higher potential of 2870mV at the completion of the charge cycle compared to 2680mV for Cells 1 and 3.
  

1  INTRODUCTION 

ETRS was contracted by Battery Equaliser Australia (BEA) to evaluate performance of an additive for lead-acid batteries. The Battery Equaliser (BE) additive is claimed to improve the performance of lead-acid batteries which are exhibiting some degree of capacity loss associated with an aging process referred to as "sulphation". The product is not marked as a "cure-all" and clearly will not improve the performance of "dead" batteries resulting from mechanical damage to lead and lead alloy grids, commoning bars and cell interconnects. Similarly, capacity losses caused by overcharging cannot be recovered.

In preliminary discussions, BEA outlined the scope of testing to date. The product had been successfully trialled in fork-lift batteries which showed evidence of significant capacity loss. Performance was based on hours of operation before recharge and it is claimed that capacity improvement was generally significant and warranted investment in a scientifically controlled research program.

ETRS was requested to submit a test program proposal and program budget to BEA for consideration. This was undertaken and approved by BEA. ETRS were instructed to proceed with the testing on 13th April 1997.

2  SCOPE of WORK

The agreed scope of work involved the following items:

• Set-up of battery test circuits in controlled environment test laboratory.
• Purchase of ex-Govt 6V 105Ah Telecom type pasted plate Pb-acid stationary batteries.
• Charge-discharge (10h-rate) conditioning cycling of batteries to establish performance characteristics and to achieve stable capacity.
• Compare battery performance before and after Battery Equaliser (BE) addition with respect to cell voltage and positive and negative plate voltage characteristics during charge and discharge.

3  TESTING METHODOLOGY

The testing program was designed to achieve a stable performance in the individual battery cells before the Battery Equaliser (BE) product was added to the cells. The cells were then subjected to a series of 10h-rate discharge/charge cycles to establish the effect of the BE additive on performance. In addition to cell voltage, the positive and negative plate potentials were also monitored throughout selected discharge and charge cycles.

A 3h-rate discharge was superimposed on the 10h-rate discharge 2 hours and 7 hours after the start of discharge. The 3h-rate was maintained for 10min which enabled additional information to be obtained on the effect of the BE additive on cell performance characteristics.

ETRS was advised by BEA to treat selected cells with 50ml of BE additive and to subject the cells to a series of discharge/charge cycles and monitor the response in terms of cell capacity improvement and identify any other detectable changes in battery performance characteristics.

4  TEST RESULTS

4.1  Battery Conditioning

The cells achieved stable capacity values after three preliminary 10h-rate discharge cycles, eight 3h-rate discharge cycles and three final 10h-rate cycles. Battery discharge capacity was found to be controlled by the positive plate capacity in some cells and the negative plate capacity in others. This is determined by the degree of negative and positive plate potential polarization at the end of discharge.

Note:  It is believed that this type of cell is constructed  with excess negative plate capacity to offset deterioration caused by aging. If this is the case, the negative plate limited cells are likely to have aged more than the positive plate limited cells. However, on the basis of the 10h-rate capacity figures after the preliminary discharge/charge cycles the cells were operating close to the nominal rated capacity.

^{On charge, there was good voltage differentiation between the PbSO₄/Pb reaction and the H₂ reaction on the negative plates in all the cells. Typically, the voltage differentiation between the PbSO₄/PbO₂ reaction and the O₂ evolution reaction on the positive plates was less pronounced. The maximum cell potential varied between 2650 and 2870 mV. This was a result of differences in both the negative and positive plate maximum charge potentials.}

4.2  Battery Equaliser Addition

The capacity results obtained before and after treatment with the Battery Equaliser additive are discussed below and summarized in Table 1. 

Battery A: 

Successive 10h-rate discharge curves for Battery A are shown in Figs 1 and 2 to demonstrate the reproducibility of the test. Figs 3 and 4 show the characteristics of the positive and negative plates during the second of the two discharge cycles. The sharp decrease and recovery in potential at 2h (and 2.7h) and 7h is produced by the higher current 3h-rate discharge superimposed over the 10h-rate discharge. The corresponding curves are shown in Fig 5.

The cells in Battery A showed the following similarities and differences in discharge characteristics after the conditioning cycles and prior to the BE addition:

• The cell potentials were very similar during the first half of the discharge cycle.
• Cells 2 and 3 had very similar capacities which were 6% higher than Cell 1.
• Cells 1 and 2 were positive plate limited whilst Cell 3 was negative plate limited.
• The -ve plates exhibited a higher degree of polarization than the +ve plates at the 3h-rate
  
• The degree of polarization was more pronounced towards the end of discharge (7h). 

The cells in Battery A showed the following differences in charge characteristics at this stage of testing:

• Cells 1 and 2 exhibited identical charge characteristics until the cell potential reached 2450mV.
• Cell 2 achieved a higher potential of 2800mV at the completion of the charge cycle compared to 2675mV for Cell 3.

After addition of 50ml of the Battery Equaliser Additive to Cell 1 and subjecting the battery to three 3h-rate discharge cycles and one 10h-rate discharge cycle, no changes were detected in the above cell performance characteristics.

Battery B:

The 10h-rate discharge curves for Battery B after the conditioning cycles are shown in Figs 6-8 together with the discharge characteristics of the positive and negative plates during discharge. The crresponding charge curves are shown in Fig 9.

The cells in Battery B showed the following differences in discharge characteristics at this stage of testing:

• Cells 2 and 3 followed very similar discharge curves through 70% of the discharged cycle but the negative plate capacity was greater in Cell 2 which extended the discharge life.
• There was a 6% capacity difference between the three cells (Cell 2>Cell 3>Cell 1).
• Cells 2 and 3 were positive plate limited whilst Cell 1 was negative plate limited.
• The -ve plates exhibited a higher degree of polarization than the +ve plates at the 3h-rate.
  

The cells in Battery A showed the following differences in charge characteristics at this stage of testing:

•  Cells 1 and 3 exhibited almost identical charge characteristics.
• Cell 2 achieved a higher potential of 2870mV at the completion of the charge cycle compared to 2680mV for Cells 1 and 3.
  

After addition of 50ml of the Battery Equaliser Additive to Cells 1,2, and 3 and subjecting the battery to three 3h-rate discharge cycles and one 10h-rate discharge cycle, the following observations were made regarding the effect of the additive on cell performance characteristics:

•  Slight improvements were detected in all the cells at the completion of the above discharge cycles (Figs 10-12) but the degree of improvement was marginal and close to the level of experimental accuracy.
• The peak charge voltage associated with the hydrogen evolution reaction was reduced by 50mV in Cell 2 but the value was approximately 120mV higher than that recorded for Cells 1 and 3 (Figs 13-15)
• On further discharge cycling, the capacity of Cell 2 improved significantly (Figs 16-18). Taking into consideration the discharge did not incorporate the two 10min 3hr-rate pulses at 2h and 7h which account for 4Ah in addition to the 10h-rate capacity, the registered improvement was approximately 8%. This was attributed to a reduction in positive plate polarisation. No change was observed in the negative plate characteristics. In addition, the maximum charge potential recovered to achieve a value close to the original level.
• The above improvement in Cell 2 remained unchanged for subsequent 10h-rate cycles.

The 10h-rate discharge curves for Battery C after the conditioning cycles are shown in Figs 19-21. The corresponding charge curves are shown in Fig 22.

The cells in Battery C showed the following differences in discharge characteristics at this stage of testing:

• Cells 1, 2, and 3 followed very similar discharge curves through the discharge cycle.
• There was a 4% capacity difference between the three cells (Cell 3 > Cell 2 > Cell 1).
• Cells 1, 2, and 3 were all positive plate limited.
• The -ve plates exhibited a higher degree of polarization than the +ve plates at the 3h-rate and the polarization characteristics were similar to those obtained for Battery A and B.

The cells in Battery A showed the following differences in charge characteristics at this stage of testing:

• Cells 1 and 2 exhibited almost identical charge characteristics and recorded a high maximum charge voltage of 2830mV.
• Cell # followed a similar charge curve but recorded a maximum charge potential of 2790mV; 40mV lower than the other two cells.
  

After the addition of 50ml of the Battery Equaliser Additive to Cell 3 and subjecting the battery to three 3h-rate discharge cycles and one 10h-rate discharge cycle, the following observations were made regarding the effect of the additive on cell performance characteristics:

• (Figs 23-25). However, Cells 1 and 2 registered a small but significant capacity loss which implies that the BE addition may have improved the performance of Cell 3.
• Apart from a small reduction in the maximum charge voltage the BE addition had no detectable effect on charge characteristics. (Fig 26).
• On further discharge cycling, the capacity of Cell 3 improved by approximately 13%. This was attributed to a reduction in positive plate polarization. BE additions to Cells 1 and 2 also produced a measurable improvement after a series of 3h-rate discharge cycles (Figs 27-29).
• The maximum potential at the end of charge increased slightly for Cells 1 and 2 (Fig 28). 

5  CONCLUSIONS

The following conclusions were drawn from the discharge-charge tests undertaken on the second hand 6V-105Ah pasted plate pure lead positive Failure-X cells regarding the effect of the Battery Equaliser additive on battery performance:

• The BE additive produced significant capacity improvements in 4 of the 7 test cells treated with the additive. The improvement was attributed to a reduction in the polarization of the positive plates during discharge.
• The change in capacity after BE treatment varied from 0% to 13%. None of the cells registered a loss of capacity after the addition.
• Improvements in capacity were not immediately apparent until the cells were subjected to a series of charge/discharge cycles.
• Several of the treated cells registered a reduction in maximum charge potential after treatment whilst others registered and increase in potential. There was some indication that the loss in potential was temporary.
• The tests to date are by no means exhaustive but the results indicate that some benefit may be gained through the use of the additive. 

Note:  Battery performance is limited by the capacity of the weakest cells and it is suggested that the effectiveness of the BE additive to bring about an overall improvement in all the cells be investigated further.

* (vii)  After the discharge has run for 2 hours, switch to 3h-rate discharge and return to 10h-rate after 10min. Repeat after 7 hours then continue 10h-rate until the cell voltage declines to 1800mV. Disconnect each cell when the cell potential reaches 1800mV.
          o Note:  This value was selected instead of 1850mV to accentuate differences in plate performance at the end of discharge.
    * (viii)  Record the accumulated ampere hours and time of each cell disconnection.
    * (ix)  At the completion of discharge, leave cells on open-circuit for 30 mins before recharge.
    * (x)  Schematic diagram of discharge cycle - Appendix III.


10h/20h-Rate Charge Cycle

 

    *  (i)  Reconnect all the cells into the series circuit, revers teh constant current power supply connections and reset the ampere hour meter to zero.
    * (ii)  Start charge at 10h or 20h-rate (depending on timing) and monitor cell potentials.
    * (iii)  Continue charge until the first cell reaches 2450mV and adjust charge rate to 20h-rate.
    * (iv)  Check time when each cell potential reaches maximum voltage plateau and disconnect the cells from charge circuit after 1.5 to 2 hours at the maximum voltage
    * (v)  Schematic diagram of charge cycle - Appendix III.


Battery Details

 

Battery Brand:            6V Exide Fuare-X Pasted Pure Plate Battery

Nominal Capacity:      105Ah (10h)

Date of Purchase:      29/4/97

Place of Purchase:     Solar Carge Pty Ltd

Previous History:       Ex-government (Telecom) no-break system (2.17/2.20V float)

Cell Condition:          No evidence of mechanical damage, grid corrosion or heavy sulphation.

 

Discharge - Charge Rates

 

* (vii)  After the discharge has run for 2 hours, switch to 3h-rate discharge and return to 10h-rate after 10min. Repeat after 7 hours then continue 10h-rate until the cell voltage declines to 1800mV. Disconnect each cell when the cell potential reaches 1800mV.
          o Note:  This value was selected instead of 1850mV to accentuate differences in plate performance at the end of discharge.
    * (viii)  Record the accumulated ampere hours and time of each cell disconnection.
    * (ix)  At the completion of discharge, leave cells on open-circuit for 30 mins before recharge.
    * (x)  Schematic diagram of discharge cycle - Appendix III.


10h/20h-Rate Charge Cycle

 

    *  (i)  Reconnect all the cells into the series circuit, revers teh constant current power supply connections and reset the ampere hour meter to zero.
    * (ii)  Start charge at 10h or 20h-rate (depending on timing) and monitor cell potentials.
    * (iii)  Continue charge until the first cell reaches 2450mV and adjust charge rate to 20h-rate.
    * (iv)  Check time when each cell potential reaches maximum voltage plateau and disconnect the cells from charge circuit after 1.5 to 2 hours at the maximum voltage
    * (v)  Schematic diagram of charge cycle - Appendix III.


Battery Details

 

Battery Brand:            6V Exide Fuare-X Pasted Pure Plate Battery

Nominal Capacity:      105Ah (10h)

Date of Purchase:      29/4/97

Place of Purchase:     Solar Carge Pty Ltd

Previous History:       Ex-government (Telecom) no-break system (2.17/2.20V float)

Cell Condition:          No evidence of mechanical damage, grid corrosion or heavy sulphation.

 

Discharge - Charge Rates