12V battery issues

[londiniumperson]

Until recently I've been using my car fairly regularly which I think has masked the fact that my battery was toast within 5 months from me owning my car from new.
The original battery was completely drained by the door handle issue in less than 5 months and also several times since.
The dealer wouldn't accept that it was an issue.

[E-vteclover]

Today my wife called me that the car did nothing.

Took the civic with a booster.
All screens black ,completely dead.

Started it up with the booster.
Everything ok and normal as usual.
Drove it 2 times and all is normal.

Sigarettelighter with 12v reader, about 20 minutes driving whas 14,5v , afterwards dropped to 12,4 v

Will get a new battery just to be sure

Car is 4 year,32dkm and still the original panasonic

Will

[E-vteclover]

No yuasa in local store.
Its a bosh 45ah 330 A ,we will see.
Gave it a full charge with my automatic charger i have before i installed it.

Strange thing now, with the factory panasonic battery when previously after 15-20 min drive the cigarette voltreader stopped charging (14,5v) and reads 12,4v

With the new battery its always charging for the moment when driving 14,4v
Even yesterday with a 30 min long drive.

Anybody knows what the extra electronic plug is on the negative-side of the battery?
A friend of my thought it whas sort of a thermal detection for the battery??
So when the battery is not in good shape anymore it gets sort of "hot" detecting with this electronic plug when in charging and so the car dont top up the battery for a while??

[EEEE]

The sensor on the negative post is a current sensor. It can tell, when applying charging voltage (14.4v to 14.8v), what current the battery is drawing. The sensor is not temperature as far as I know.

As the battery reaches is chemical full charge, the current that goes through the battery tapers off and drops down to a threshold. At this point, this is when most chargers will switch off bulk/absorption charging and go into float charging (eg, fully charged). You can see this charging curve/process by searching for CC/CV (constant current, current voltage).

The old battery probably couldn't absorb the charge, so the current wouldn't taper off and indicate 'full' , so it most likely just kept charging. What you see with the new battery is correct (as far as the e is concerned), it will charge at full voltage until the black sensor senses the current tapering off, then the voltage is lowered to avoid wasting energy needless gassing off the battery (but 12v batteries actually like a bit of this and that's what the e battery probably doesn't last very long).