smileypete Posted June 17, 2012 Report Share Posted June 17, 2012 (edited) Re. voltage: after equalisation and taking the batteries off the shoreline for a few hours, the voltage readings dropped dramatically just as before (see my first post) i.e. from 12.65 down to 10.2 volts (using Victron Monitor) after drawing 80 amps (from fully charged) in just over 5 hours; each individual battery also gave exactly the same reading of 10.2v. Taking all load off then led to an increase in the Monitor reading to 12.37v, with each individual battery also reading 12.39v. Could be useful to take a set of SG readings after this happens, to see if the batts are being discharged equally or not. Edit: Just another thought, what brand are the existing batts? cheers, Pete. ~smpt~ Edited June 17, 2012 by smileypete Link to comment Share on other sites More sharing options...
blodger Posted June 17, 2012 Report Share Posted June 17, 2012 (edited) Re. voltage: after equalisation and taking the batteries off the shoreline for a few hours, the voltage readings dropped dramatically just as before (see my first post) i.e. from 12.65 down to 10.2 volts (using Victron Monitor) after drawing 80 amps (from fully charged) in just over 5 hours; each individual battery also gave exactly the same reading of 10.2v. Taking all load off then led to an increase in the Monitor reading to 12.37v, with each individual battery also reading 12.39v. I picked up a dumped set of batteries from the canalside about five years ago and rejuvenated them through charging and equalisation and used them satisfactorily for about four years as another bank. They are a bit like yours now methinks beyond help by equalisation and with a much diminished capacity which means you soon see sub 12v voltages when loaded. They are sat on the foredeck in a box now as a bit of a solar dump used to power 'security' lights and radio when moored and I sometimes hook the laptop to them to give them some excercise and save the batt upon which I can rely more. Sounds like it is time another use was found for yours after you have worked out what has snookered them so soon such as using them ETA2 Batteries need regular periodic equalisation but comes a time when it does not achieve a lot. Its seems yours have been suffering equalisation type voltages from new and have had enough of it I am afraid. Edited June 17, 2012 by blodger Link to comment Share on other sites More sharing options...
Chris Pink Posted June 17, 2012 Report Share Posted June 17, 2012 Re. voltage: after equalisation and taking the batteries off the shoreline for a few hours, the voltage readings dropped dramatically just as before (see my first post) i.e. from 12.65 down to 10.2 volts (using Victron Monitor) after drawing 80 amps (from fully charged) in just over 5 hours; each individual battery also gave exactly the same reading of 10.2v. Taking all load off then led to an increase in the Monitor reading to 12.37v, with each individual battery also reading 12.39v. I can't find original so I'll quote this one. The readings above; I'll assume you mean 80Ah not 80A (400Ah). Your voltage reading under load is pretty meaningless, so the 12.37 after 80Ah is not U/S batteries. It's really not bad, implying a capacity (without doing any maths) of 350-500Ah. 80Ah in 5 hours is average 16A (what load?) and while I wouldn't expect that load to drag the batteries down to 10.2 the recovery, to me, suggests a connection problem. Making reliable connections for high current 12V is not trivial. I am posting against my better judgement as I think you need to call in some expert help. On-site diagnosis would be so much easier than this remote wibbling. And back to solicitor...(sorry) an initial consultation, which could be free, will at least tell you where you stand on responsibilities and possibilities. Link to comment Share on other sites More sharing options...
blodger Posted June 17, 2012 Report Share Posted June 17, 2012 (edited) I can't find original so I'll quote this one. The readings above; I'll assume you mean 80Ah not 80A (400Ah). Your voltage reading under load is pretty meaningless, so the 12.37 after 80Ah is not U/S batteries. It's really not bad, implying a capacity (without doing any maths) of 350-500Ah. 80Ah in 5 hours is average 16A (what load?) and while I wouldn't expect that load to drag the batteries down to 10.2 the recovery, to me, suggests a connection problem. Making reliable connections for high current 12V is not trivial. I am posting against my better judgement as I think you need to call in some expert help. On-site diagnosis would be so much easier than this remote wibbling. And back to solicitor...(sorry) an initial consultation, which could be free, will at least tell you where you stand on responsibilities and possibilities. I had extrapolated less generously summizing perhaps another 60ah to 12.2 and 50% SOC so 140 + 140 say 300ah bank tops. I thought 5 batts but see it says 6 batts boiled in OP and IIRC 50% capacity is a general working limit. Edited June 17, 2012 by blodger Link to comment Share on other sites More sharing options...
Up The Creek Posted June 21, 2012 Author Report Share Posted June 21, 2012 I can't find original so I'll quote this one. The readings above; I'll assume you mean 80Ah not 80A (400Ah). Your voltage reading under load is pretty meaningless, so the 12.37 after 80Ah is not U/S batteries. It's really not bad, implying a capacity (without doing any maths) of 350-500Ah. 80Ah in 5 hours is average 16A (what load?) and while I wouldn't expect that load to drag the batteries down to 10.2 the recovery, to me, suggests a connection problem. Making reliable connections for high current 12V is not trivial. I am posting against my better judgement as I think you need to call in some expert help. On-site diagnosis would be so much easier than this remote wibbling. And back to solicitor...(sorry) an initial consultation, which could be free, will at least tell you where you stand on responsibilities and possibilities. Thank you all. Batteries are from CPC; they are unnamed ......... The 80 ah over 5 hours (average 16 amps) comprised the usual evening load, for me: a fridge freezer, a few ceiling and side lights, plus TV/radio. I agree it's time for expert help (including legal), which I am currently arranging. When/if these problems are finally resolved, I promise to post the outcome on the forum! Bob Link to comment Share on other sites More sharing options...
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