Car battery voltage 7.5V

Lex Luthor

Came out this morning to start the car and immediately after turning it on the battery charging symbol came on

Got a few dashboard warning lights and after they didn't clear for a few minutes I decided to switch car off and try again, however this time it wouldn't start by itself and needed a jump start

Got it jump started and most of the lights cleared however after a couple of min I disconnected the jump leads and all the dashboard lights came on again. Engine then sounded like it went into a limp mode so switched it off

Checked the battery voltage with a multimeter and its 7.5V

Is the battery gone beyond re-charging at this point at 7.5V? Reading online it indicates its dead so a replacement needed?

Thanks

dar_cool

Yes id say the cold weather killed it. If you have a battery charger id try charging it but more than likely its dead

CJhaughey

New battery time I am afraid, once they drop below 10.5ish they very rarely recover much capacity.
You could try charging slowly with a dumb charger at low amps and see if you get anywhere but I doubt it and its not really something you want to fail another time where its more inconvenient.

toyotafan

As far as I know, once a car has started by a jump start for example, it wont sound like this, as its alternator should provide enough power for the whole system. I would recharge battery and check alternator in this case.

Lex Luthor

Update
Dealer charged battery over 8hrs approx. on a slow charge
Found a loose connection from the battery in the fuse box which was coming from the alternator, hence the loss of charge
Got car back today and running grand

CJhaughey

Keep an eye on the battery, the slow charge might have saved it but no battery likes being run that low in these temperatures.