battery charging question

[Jaguar Fan]

I'm cross posting this in this section thinking it might be better to post it here rather than free parking.

I stupidly left the dome light on in a Smart ForTwo for several weeks, draining the battery to absolute dead.

I'm confused about how long to charge the battery with a standard auto battery charger.

The specs for its little battery are 12V, 61AH, 540A.

The chart for the auto battery charger are in units of CCA or RC.

I haven't figured out how to convert them. Any thoughts? Here is the table from the charger manual.

Many thanks

 

[BillK]

jf,
I would charge it on the lowest settiing, in your case 2 amps. Most battery chargers have an automatic cut off that tells you when the battery is charged. If your charger does not have an automatic cut off then it will probably take around 15 hours for a full charge. ( 61 Amp Hours divided by 2 amps = 15 hours )

Dont be a bit surprised if the battery is ruined and will not take a charge Any time you drain them all the way and leave them like that for a while, its a good possibility.

 

[ddawg16]

Charge it for a couple of hours.....when it starts to get warm....it's charged....once a battery if fully charged, it dissapates the excess energy as heat.

 

[Torque1st]

( 61 Amp Hours divided by 2 amps = 15 hours )

Dont be a bit surprised if the battery is ruined and will not take a charge Any time you drain them all the way and leave them like that for a while, its a good possibility.

With a constant current charger that calculation would be close. The numbers on his chart seem to indicate he has a simple charger without any fancy electronics.

As you say the battery may be dead. Some say a jolt of 120VAC will revive one. I have not had any luck with it tho.