Patrick Coppens wrote: > Alan Stepney wrote: > >> OK, for todays silly suggestion, check the charger. >> >> There is a possibility that the rectifier has gone short circuit, and >> putting, say, 20+ volts AC into the battery wont make it very happy. >> >> http://www.alanstepney.info >> Alan Stepney's Model Engineering, steam, and workshop pages. >> >> MODEL ENGINEERING DISCUSSION LIST. >> >> To UNSUBSCRIBE from this list, send a blank email to, >> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject >> line. >> >> >> >> > As an electronics engineer, I tend to agree, with some of you, who > state,that the battery has been producing an excess of H2 and some other > gases, that come with charging a battery of this kind. > It is unlikely, that the vent would not become "unblocked" when gas is > produced.(and these batteries have an added "safety valve") > What is likely in my opinion, is that the load current was rather high, > and that the amount of gas produced was higher then acceptable. > On top of this, you are dealing with volatile gases that are heated up! > this occurs because of the loading. > All this together, is still an unlikely scenario, though. > > I suspect, that because of the frequent moving in and out of the battery > (out and in the car) that some plate(s) lost part of their (lead) charge > and shorted. > If you add that to the above, you might get a result as shown in the > pictures. > On the other hand, most deep-cycle batteries, (I have worked with this > type more then the others, but they are basically the same) I have seen > in this state, were simply connected wrongly to the charge current.... > And that, will kill a battery every time.... > > Also, there is something to be said, in connecting batteries in series, > only if they are of the same brand and type. Every manufacture makes his > batteries according to his specifications, and the "internal resistance" > will differ, with the brand and type. > A difference in "internal resistance" will eventually cause degradation > of the plates (and loose bits!) and internal short circuits. (one > battery is using current from the other, as it passes trough the plates, > as it were..)The internal resistance starts to differ more and more as > the battery heats up, and the problem gets worse... > So beware! If it is really needed to switch two batteries in series (Pb > batteries) make sure that they are both new, and of the same make and > time. Try and charge them when switched in series, with a 24 V charge. > If the choice is there, a long and slow charge is always far better then > a slow "burst" charge (or whatever they call it these days!) > If possible use "deep-cycle" batteries (the type used in caravans and > the like) These are designed for erratic discharge and will last longer > for the kind of application suggested in this case. > As a new battery needs to be bought for this application anyway, you > might consider a 24V one and be done with all the possible trouble > mentioned above... > > > Cheers > Patrick > MODEL ENGINEERING DISCUSSION LIST. > > To UNSUBSCRIBE from this list, send a blank email to, > modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject > line. > > > correction : slow "burst" should of course be fast "burst charge"!!! MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.