Now that is the answer I needed. That is, older batteries may top out at a charging voltage less than a new one, and so if the charger is not very smart, it never reaches the cutoff voltage it expects. Never tapers the current and never indicates Full... even though the battery has accepted all it is going to.
Im just trying to get enough juice back into it so I can drive the 1 mile to where I store it Thanks, Bob -----Original Message----- Subject: Re: [EVDL] Lead Acid question On 25 Jul 2016 at 11:55, Robert Bruninga via EV wrote: > Im charging my 10 Lead Acids one at a time with a common 10A car > battery type charger. Usually they come from low to high on the > "percent" meter and then when they get to 100%, an LED comes on and > the current tapers to zero. > But I have one battery that seems to just stay at mid range and after > 20 hours is not topping off. And battery is not excessively bubling > nor is it showing much heat gain. Note that I am not an electrochemist, just someone who's used batteries for quite a few years. There are other folks here with far more experience and knowledge than I have, but none of them has answered your question as yet, so I'll take a run at it. :-\ First, one thing that makes remote diagnosis tough is that you haven't told us anything about the charger. Automatic chargers' algorithms can affect the symptoms you see with a problem battery. That said ... It's normal for batteries' maximum on-charge voltage to fall as they age. Many automatic chargers know naught of this; they treat all batteries the same regardless of age. They'll undercharge new batteries and/or overcharge old ones. They may not shut off when they should. They may claim a battery isn't charged when it's as full as it's ever going to get. However, the fact that you're seeing this symptom with only one battery in your pack suggests to me that that battery might have at least one bad cell. If you can't get its voltage to rise above around 13 volts with the charger charging it (not open circuit), and after a few hours of rest if falls to around 11 volts (open circuit), then that's probably what's wrong. In spite of what the snake oil salesmen claim, there's no cure for this, short of replacing the battery. As I suggested above, at least in my experience, the way automatic chargers behave can make it harder to diagnose battery problems, unless you know a lot about batteries and the charger's design. Charging with a manual charger or a regulated power supply, and discharging with a 25 to 75 amp load, should tell you much more about what's really going on in that battery. David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
