Everything depends on the current rate which you are using, battery design and frequency (how many cycles). If we are speaking about standard flooded batteries than the higher current rate during cycling (step load change) will lead to longer cycle life time (considering constant Depths of Discharge). Very small current rate can lead to the ageing effect called sulfation which was already mentioned by Holger.

For the VRLA (Valve-Regulated Lead-Acid) batteries the current rate during charging is influencing the COC (Closed Oxygen Cycle) which is an exothermic effect and increases the battery temperature. If your current rate in this case will be too high than you can increase the battery temperature to the level that will harm the battery and decrease its life significantly.

I guess you have to study the ageing effects of the lead-acid batteries a bit. Afterwards you will definitely be able to answer all your questions by yourself.

If you have any further questions dont hesitate to ask.

I can recommend you the following literature:

1) D.Rand et al., „Valve-regulated Lead- Acid Batteries“, 1st Edition, Elsevier, 2004

2) G.Pilatowicz et al. "Simulation of SLI Lead-Acid Batteries for SoC, Aging and

Cranking Capability Prediction in Automotive Applications", JES, 159(9), A1410 (2012)

3) P. Ruetschi, "Aging mechanisms and service life of lead–acid batteries", JPS, 127, 33 (2004)

Everything depends on the current rate which you are using, battery design and frequency (how many cycles). If we are speaking about standard flooded batteries than the higher current rate during cycling (step load change) will lead to longer cycle life time (considering constant Depths of Discharge). Very small current rate can lead to the ageing effect called sulfation which was already mentioned by Holger.

For the VRLA (Valve-Regulated Lead-Acid) batteries the current rate during charging is influencing the COC (Closed Oxygen Cycle) which is an exothermic effect and increases the battery temperature. If your current rate in this case will be too high than you can increase the battery temperature to the level that will harm the battery and decrease its life significantly.

I guess you have to study the ageing effects of the lead-acid batteries a bit. Afterwards you will definitely be able to answer all your questions by yourself.

If you have any further questions dont hesitate to ask.

I can recommend you the following literature:

1) D.Rand et al., „Valve-regulated Lead- Acid Batteries“, 1st Edition, Elsevier, 2004

2) G.Pilatowicz et al. "Simulation of SLI Lead-Acid Batteries for SoC, Aging and

Cranking Capability Prediction in Automotive Applications", JES, 159(9), A1410 (2012)

3) P. Ruetschi, "Aging mechanisms and service life of lead–acid batteries", JPS, 127, 33 (2004)

I am also looking for same

Sorry guys, I cannot just send you the references which I mentioned in my previous post because of the copyrights. However, in many cases one can get access to these journals through the university so check if it is possible at your alma mater.

Holger mentioned a couple of important things in his posts above. I will just sort this big portion of knowledge in this post and add some comments from my side.

1) There are irreversible ageing effects and reversible ones -->irreversible: corrosion, degradation of the active material (shedding), water loss (VRLA) --> reversible: sulfation. You can nearly fully restore the capacity loss from sulfation by implementing a correct charging strategy with refresh charging once per a while.

2) In the all battery storage systems there is a calendaric ageing and cyclic ageing. In PbA the calendaric ageing strongly depends on the temperature, state-of-charge and charging strategy. If you want that your battery live long than avoid high temperatures >25 deg C, deep discharging and intensive overcharging to often. PbA batteries in contrary to Li-Ion love high SoCs.

3) For a cyclic ageing the deeper cycles you run, the faster the end of life of the battery will be reached. There are many factors as Holger mentioned but this is the main one. Additionally, there are different designs and applications, here are some numbers:

SLI car batteries: quality scattering is huge(each manufacturer and technology show entirely different performance). It may even happen that the same battery from the same manufacturer produced one month later or in a different factory ages much faster. --> up to 500 cycles --> 50% DoD cycles at 25C with high current and EN CHA strategy. Generally these batteries are not designed to be cycled very often. In the near future it will change a lot because of the vehicles with micro hybrid and extended micro hybrid functionality.

Heavy duty traction batteries and PV systems (forklift tracks, wheelchairs): up to 3500 cycles --> 50% DoD cycles at 25C with high current and EN CHA strategy

USV batteries and telecommunication batteries: These batteries are generally cycled very seldom and being kept continously at the float charging and they reach up to 25 years of service life (Plante cells)

The battery service life = f(cycle depth) is very non linear, an example can be found on a Hoppecke webpage (Holger menitoned it as well) --> http://www.hoppecke.com/content/view/full/1539

4) The are other effects such as acid stratification, dendrites (micro shorts), antimony poisoning and inhomogeneous current distribution which has to be taken into consideration for an accurate SoH estimation (State-of-Health)

5) An equation which you can take to calculate an actual available capacity is:

SoH = f(I,T,ageing) for full state of charge = (CN/(I*20))^(k-1)*(1 + αd (Tin(t) − 25◦C))

*(1 − Closs,deg(t) − Closs,corr(t)). where: k is a Peukert constant; αd is a capacity temperature coefficient; Closs,deg and Closs,corr are the normalized capacity losses due to degradation and corrosion respectively. Used SoH corresponds to the dynamic available capacity of the battery and is normalized to the nominal capacity. You can take k = 1.2 and 1.1 for flooded and AGM batteries respectively; αd = 0.6%/K.

6) The only way to really check the actual capacity of the battery concerning ageing is an capacity test. Don't believe in any wonderful device which is being sold as solution "for all your problems".

7) There is no such thing as an optimal and cheap battery for everything. The ones which are optimized for cycling are not so much high power ones and cost much more. The ones which are high power ones cost much less then heavy duty ones but are very bad in cycling. The valve-regulated ones are generally better than flooded but they cost more and are even more complex.

8) Batteries are generally very complex. Modelling them as a voltage source with internal resistance only as many electrical engineers etc. are doing is very very simplified and good only for a very very limited conditions. ;]

I am also agree with Holger

Here is a paper that you might find useful. It relates to lead acid batteries. http://www.researchgate.net/publication/234165982_00PSC-135_Induced_Stirring_at_Lead_Acid_Battery_Electrode_Interfaces/file/79e4150fb34f9c7022.pdf

Article 00PSC-135 Induced Stirring at Lead Acid Battery Electrode Interfaces

NREL published an interesting report on this:

http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/evs17pres.pdf