Luis, I would say that this battery is gone and will have to be replaced.=20 Deep discharge LABs need to be almost fully discharged before you=20 recharge them. Regular auto batteries are designed to put out a lot of=20 current for a short time and then to be quickly charged up. Any LAB that=20 is left in a discharged or partially discharged state will sulfate. They=20 will lose a substantial part of their capacity. They will also become=20 very hard to recharge. Sometimes you can put them on a trickle charger=20 and let them charge for a long time at a very low current. You should be=20 able to find information on how LABs work and how to cared for them on=20 the Internet. The part about them being sensitive to sharp blows and shocks is=20 absolutely correct. In fact they can be ruined by the counter man coming=20 out and dropping the battery on the floor or on the counter. Do not ever=20 accept a battery that you know has been subjected to this kind of=20 treatment. The auto battery manufacturers estimate that up to 40 percent=20 of all warranty claims are do to a battery being subjected to this kind=20 of treatment by someone between the plant and the end customer. Thanks, rich! P.S. Sorry about your battery. rich! On 8/31/2014 6:20 PM, RussellMc wrote: > On 1 September 2014 02:47, Luis Moreira > wrote: > >> ... >> alarming on low voltage and when I check, it was quite low on voltage. >> I tried to charge it and although the charger is saying it is charged as >> soon as you remove it, the voltage drops of straitway. >> Today I removed the caps and charged it again but noticed that one of th= e 6 >> cells is not bubbling up. >> Does this means that, that cell is shorted? Is it anyway I can repair i= t? This was written by RussellMc, > What 'quite frequently' happens is that the conduction path is broken=20 > somewhere inside the battery. This can happen if you hit a "bump" at=20 > high speed (ask me how I know :-) ) or otherwise cause a large=20 > physical impulse to the battery . I've read [tm] that a significant %=20 > of battery failures are for this reason. Auto batteries in rough use=20 > apparently fail often in this manner and AIUI spiral plate=20 > construction (eg CYCLON? *) batteries are far less prone to this=20 > failure mode. I do not know where the weak points are or if it is the=20 > cell to cell interconnects that fail (seems most likely) or if a=20 > partial cell can disconnect. While the latter seems less likely it=20 > would leave one cell with low capacity and it would probably emulate=20 > what you see. (The equivalent situation occurs in PV panels with=20 > series cells where one cell fractures part way along its length). If a=20 > battery cell is fully shorted you would expect the maximum voltage=20 > that it would exhibit just after charge is removed to be substantially=20 > lower than if all cells were present Russell *=20 > http://www.enersys.com/Cyclon_Batteries.aspx=20 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .