Czechman

My battery went dead from the car not being driven. What's best?

1. Jump start and drive it for a while to charge the battery? I read somewhere where an alternator won't charge a dead battery.

or

2. Charge the battery. Anything special I need to do before charging, like disconnecting anything first?

Thanks for any help.

Comfortably Numb

What I would do if I could is disconnect the battery completely and use a charger on it. But if it is as dead as it sounds you may not be able to get to it so a jumpstart might be necessary just to reach it.

unique_w

Agree - a slow charge using a 6 amp charger that will reduce current as it charges is better than a fast charge. In the future you may want to use a low amp Trickle (float) Charger to keep the battery up to par if the vehicle is not going to be used for long intervals. They can be found on eBay under Trickle Charger.

Czechman

If I do use a trickle charger can I connect it to the jump terminals under the hood or do I have to connect it directly to the battery?

solman98

I would connect directly to the battery.

fastsuv

Don't use the car to charge a completely dead battery. The alternator will put out a lot of current, which will charge at too high a rate and sometimes will damage the alternator. The current will only be limited by the alternator output and/or the wire size between the alternator and battery. Look at the
paperwork that comes with a new (or reman) alternator and often they will warn that the warranty is void if you use the alternator to bring up a dead battery.

The general rule for charging flooded lead-acid batteries (most car batteries) is to charge them at a max rate of 20% of the capacity of the battery. Most car batteries are about 80-100 amp-hours so the max charging rate should be about 16-20 amps.

These are the rules that RV owners use to charge their batteries for maximum battery life.

Steve

unique_w

Agree

Laco

I have used a smart charger several times, connected to the terminals under the hood, though I use the engine block for the ground. Have never had a problem doing this. The newer 'smart' chargers will not damage your battery, and will float it, when it does reach full charge.

JimZ_HHR

If it sits up for a long time in sunlight... try a solar maintainer, plugs into Aux power outlet.

Marzipan

The Owners Manual should tell you what to do when you have a dead battery.... at least the 2008 manual explains this. You really can't get better advice than the manufacturer's instructions.