Do you have any idea how many amps the battery is accepting, and for how long, before voltage rises to the mid 14's??
I got a call from a neighbor the other night. He said he wanted a battery reccommendation as his battery just died and just caused his new to him vehicle to stall while driving home, sitting at a traffic light. He got a jump froma jumper pack and was able to drive the mile home.
I said hold on lets check the charging system. It was as I suspected, not charging.
The battery was 12.06v when I checked.
KNowing it was going to be outide overnight with some possible rain, I got my Schumacher 'smart' charger, even though it is Bipolar. Instead of my power supply which I trust much much more.
I set it on the 12 amp setting and watched the volts and amps.
on the 12 amp setting it was outputting 14 amps, and the battery voltage rose slowly from 12.06 to 13.41 in 5 minutes.
if 14 amps had allowed voltage to quickly rise to 14.7v, it would say to me the battery is sulfated with little remaining capacity.
After 5 minutes I disconnected the charger and had him start the engine. It was not charging the battery.
I set schumacher for 25 amps and let it go, 26 amps had voltage rise to 13.8v in about 10 minutes. I declared the ~ 65Ah Deka starting battery, is still strong. I wound up lowering it back to 12 amps and let it go overnight. the watt meter said it had accepted 59AH in those 12 hours before I removed the charger.
The voltage 2 hours after removing the charger was still 13.4v.
The vehicle had never cranked to life faster since he bought it.
I found some loose connections, and was able to get 14.4v with engine running.
Watching how many amps flow at a voltage is extremely enlightening as to battery state of charge and state of health, but almost nobody seems to realize this, and just think voltage alone tells everything, or the lights on a charger say all is well.
So your battery could have been discharged below 10.5v(100% discharged) and froze, and any attempts to recharge it could be fruitless, but if you saw battery voltage slowly only climb as it accepted 12 amps hour after hour, that would say other wise.
But without seeing how much amperage is flowing at that voltage, you get to trust the internet and some smart charger's reading.
So many smart chargers will see a voltage when first hooked up and declare a state of charge as a percentage. This % can be way out of line with reality.
However an Ammeter display along with a voltage display would be extremely enlightening and harly much more $$ to incorporate into the charger.
For thosreaders to whome this makes sense, this simple device can allow you to see what your plug in garage charer is actually doing:
14$ inline wattmeterIt will handle upto 25 amps continuous without issue and will allow you to see just how smart, or dumb, your garage charger is.
A depleted battery which accepts a lot of wattage for a while without heatinvg excessively is a battery still capable of preforming its duty, once recharged.
A depleted battery whose voltage quickly climbs to the mid 14s with less than a dozen amps, is likely done and done, and worth the core charge only.
