WotEver Posted January 9, 2018 Report Share Posted January 9, 2018 (edited) 1 hour ago, nicknorman said: No you are misreading it. It says that exhaustion of acid is the determining factor at high discharge rates (this is the peukert effect) but the comment about the loss of surface area is not in the part of the sentence talking about high discharge rates. That is completely wrong. They are saying that it’s interesting to study the EOD characteristics as described by Peukert, and while slow dispersion might occur, the main factor is the clogging of the pores. It’s all the same paragraph; it’s not a new subject. Edit to add: the whole paper is about Peukert and that opening paragraph simply gives an overview. http://www.academia.edu/18308145/Peukerts_Law_of_a_Lead-Acid_Battery_Simulated_by_a_Mathematical_Model 1 hour ago, nicknorman said: As an aside, this effect does help me understand what happened to my cheapo leisure batteries that dropped to 50% capacity (lost 220AH) after 6 months leisure use and a proper charge regime. I found that an equalisation charge that just put in perhaps 20 AH (most of it lost to gassing) recovered the lost 220AH. Presumably I had a small quantity of some hard sulphate blocking a large proportion of the pores of the battery which was cleared by the equalise. But you already know this. Hardened sulphate takes a lot of shifting. Or are you drawing the distinction that a small amount of charge energy released a large amount of capacity? Yes, that would be the ‘Clearasil Effect’ Edited January 9, 2018 by WotEver Add description & link Link to comment Share on other sites More sharing options...
nicknorman Posted January 9, 2018 Report Share Posted January 9, 2018 1 hour ago, WotEver said: That is completely wrong. They are saying that it’s interesting to study the EOD characteristics as described by Peukert, and while slow dispersion might occur, the main factor is the clogging of the pores. It’s all the same paragraph; it’s not a new subject. Edit to add: the whole paper is about Peukert and that opening paragraph simply gives an overview. http://www.academia.edu/18308145/Peukerts_Law_of_a_Lead-Acid_Battery_Simulated_by_a_Mathematical_Model But you already know this. Hardened sulphate takes a lot of shifting. Or are you drawing the distinction that a small amount of charge energy released a large amount of capacity? Yes, that would be the ‘Clearasil Effect’ Last bit. Yes, the Clearasil effect! Regarding the paper, I see nothing to support your contention, and of course it was a contention that was specifically refuted by the evidence in the other paper you put on here. In the paper you have linked to today, it repeatedly says that plate active area is improved at higher discharge rates. The summary says it all: With this accurate model, the analysis of the performance characteristics of a flooded LAB and modeling allowed us to simulate the causes for EOD. At high rates, the EOD is caused by an exhaustion of sulfuric acid in the positive plate. As the rate decreases, the cause of the EOD is actually due to clogging the pores by the sulfation of the electrodes, as indicated by the significant reduction in the electrode active surface area, and therefore preventing the reaction to occur where active material might still be available So the pore blocking effect is predominant at low discharge rates - the normal reason for EOD. At higher rates the exhaustion of sulphuric acid is the reason for EOD - temporarily of course, until there is time for diffusion to bring new acid to the reaction zone. That is the Peukert effect. Try harder next time! Link to comment Share on other sites More sharing options...
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