Battery Recharge - stoozguy
Hi - how long should I need to drive my car after jump starting it so as to recharge the battery? The reason I ask is that I did so for about 25 mins last night but battery was still flat when I went to restart this morning. Not sure if it's relevant but car is a Jag XJS and battery had been fine up until recent cold weather.

Cheers,
Jon
Battery Recharge - madf
about 1 hour I guess.. not stop/start but long journeys...

madf


Battery Recharge - Cliff Pope
In my experience a battery that has merely been run flat, but is otherwise in good condition, will charge enough to restart after only a few minutes running. But then it is quite hard to flatten a good battery.
I'd say the battery has had it. Charge it up on the bench and see if it will hold its charge.
Battery Recharge - martint123
I think charging current is recommended to be 1/10 of the capacity. So a 60 AmpHour battery would be 6 amps for 10 hours.

It takes quite a bit to get truly fully charged.
Battery Recharge - mjm
Alternators throw out a hefty current. It sounds to me as if the battery is well on its way out. It may pay to give a low rate trickle charge overnight.
Battery Recharge - Civic8
I would be inclined to check both battery and alternator..if Alternator not charging properly. Battery isnt going to get enough charge.No matter how long you run engine
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Steve