How Long to Trickle Charge a Dead Battery?
 

My car has been down due to some mods I've been working on. Combined with some business trips, I haven't had a chance to drive it for about 4 weeks. Last weekend, when I went to open the car via the key fob....nothing. Completely dead.

I hooked up my trickle charger and it's been two days and it still indicates that the battery is charging. Does it normally take this long? The battery is a 1-year old AC Delcom OEM replacement. BTW, it's August in Florida, so lesson learned. :ack:

July/August in Florida is my "winter". Too damn hot to drive a vert.

Could indicate a dead cell....from being totally discharged. Try to charge another day or so and if that doesn't work, have it load tested to check for a dead cell. You may need to go shopping for a new battery.:thumbs:

Usually at 1 amp approx 10 hours

Are the setting right on your trickle charger? I know some let you change the amount of amps and the voltage of the battery. I left my lights on last week and hooked up the trickle charger and left it on for 2 days just to be sure that it got a deep charge. Does your car start up now?

Should not take two days to recharge. Might want to get the battery tested and see if it has gone bad.

You dont say which type of charger you're using. The "battery tender" type of charger takes longer to recharge the battery. i just recharged my boat battery (from dead) and it took 3 days - 1 day on a normal charger and 2 days on my Accumate.

:iagree: This was about the amount of time it took to bring back my discharged battery.
I had left the interior lights on our Grand Prix for 24 hours.
Just took it slow and easy with a 1.5 amp maintainer/charger :thumbs:

Thanks for all the feedback. I am using this 12V "Battery Tender Plus" trickle charger.

http://i499.photobucket.com/albums/r...teryTender.jpg

I hooked it up Sunday night and it's still not charged. The Key Fob is not unlocking the car and the hood light does not go on. Still completely down.

The charger does display the steady red light which indicates that the battery is charging. I've had the car down for over 4 weeks before and the battery never died, however it's been blazing hot the last few weeks here in Florida. I did remove the sun visors as part of the interior mod project I'm working on, however I don't think disconnecting the vanity mirror connections should have negatively effected the battery (per my other thread).

The battery is only one year old, so the warranty should cover it. Unless they have a non-use clause.

I've had the same problem

My Battery Tender will NOT charge a totally dead battery still in the car & hooked up to the car , I think because the computer(s), interior lights, hood light, and other stuff takes more than the trickle and it CAN'T catch up ...

I the past I used a regular 10 amp charger for a few hours to get some juice into the battery, then switched to the tender ... over night or longer

Worked perfect

Your results may vary ...

Thanks. I don't have any other type of charger (yet). Can I jump the battery and then switch over to the trickle charger?

Better yet - disconnect the battery from the car, then use jumpers, and let the jump stay on for 30 minutes or longer. That should put some life in the dead battery without effecting the vette electrics - then disconnect the jumper.

then re-connect the battery to the car

when you re-connect the battery to the car if you hear alot of clicking. the battery is still too low - maybe repeat but for a longer period ...

some may dis-agree with me, but I've done exactly that before I bought a 1/10/100 amp charger (with auto shut off).

Thanks. I will try that. Do you know if there is any long-term damage to the battery after it's recharged?

Don't know about your area but around here you can take the battery out and take it to an O'Rielys and they will put it on a tester for free (my favorite price !! :D ). Should be able to tell if you have a cooked battery or a dead cell.

Also, a CTEK battery charger is supposed to be able to recharge a completely dead battery still in the vehicle.

Years ago I did what you did (let the battery go DEAD), like 5 times in 3 years, didn't seem to hurt the battery, but eventually the battery needed replacement, anyway.

I never had any damage to the car or battery.

A symptom of a failing battery is it won't hold a charge for more than a few days (or less), and yours didn't have that symptom ... My guess is your battery is fine. Just don't let it go dead regularly - overall that's BAD for any battery.

A charger can charge forever and will never charge the battery if a battery cable end is loose or dirty. Are you going directly on the battery post with the charger clamps or just on the battery terminal ends?

Yep. Lessoned learned. I've had the battery run down before, however this is the first time it has been completely dead. Since the battery is only 1 year old, I'm hoping once I recharge it, everything should be OK. I will never let it go this long again, especially in the summer.

Once it is fully charged or if you buy a new battery, keep your tender plugged in if you think it is going to sit for more than two weeks. I keep mine plugged in pretty much all year round (not a daily driver) to make sure it doesn't discharge. There are a few ways to connect and dissconect the battery tender without the hassle of popping the hood every time (cigarette lighter, longer pigtail off battery, etc..)

Thanks for all the replies! I purchased one of these bad boys and completely re-charged the battery in 3 hours! Since it's still down due to the interior being reworked, I re-hooked up my original trickle charger which is now showing the battery as fully charged.

This new unit also has a maintenance mode with the digital read out, however it takes up more space than the trickle charger. I'm glad I have it around the garage. :thumbs:

http://i499.photobucket.com/albums/r...tuff/XC103.jpg

:cheers:

My experience with a battery tender and a dead battery in my 2012 Vette is that the car's passive electronics simply use too much juice - with or without a hood lamp and the alarm activated - for the tender to charge the battery. I've always had to remove one of the battery cables before attaching the tender - in which case I've achieved a full battery charge within 48 hours plus or minus a few (temperature may affect the amount of time required).

If you have the luxury of time. Try this before fussing around with trying to figure out if your battery is shot.

I agree... but he probably figured this out 4 years ago. :willy:

Not for him. But for others who might search on this topic.

just a heads up for the future. if you have a gel cell type battery (optima etc) that has gone dead (and that charger is a digital one with an automatic sensing system) it is possible that the charger won't even recognize it has been attached to a battery to switch to the charging mode. (don't ask how i know this, lol). i solved the problem by hooking the battery (still in the car) to a running car via jumper cables for about 20 minutes or so to give the dead gel cell some life. then the digital charger recognized it was attached to a somewhat dead battery and flipped automatically to the charging function. it took approximately 36 hours to bring the optima back to a normal full level and was still going strong when i sold the car about a year later. just something to be aware of if your charger is one of those that automatically senses the function to perform. glad you got your problem solved.

I have seen that before also....a battery is dead and the trickle charger will not charge it...so I have hooked it up to a full size charger and charged that way and I have also pulled a battery before and take to the auto parts store and let it sit on their charger for a couple days.

When I worked at the NAPA store we had the battery tester that checked for both available charge and load tested the battery. Unless technology has changed you can't load test a battery that has no charge.

Back in the 60's the way you trickle charged a battery was to remove the battery from the vehicle and sit it on a piece of 2x10 wood. Then you removed the caps, made sure the acid level was to the correct level and hooked up the trickle charger. A couple days later when all the cells were bubbling and some liquid had spit onto the top of the battery and the battery was warm to the touch you checked the voltage. Of course you can't do this with an AGM battery.

With my 2000 I run the NAPA battery tender. If the car sits a week without being driven it can take three days to achieve full charge according to the tender lights. The battery is less than three years old and is a NAPA 770 CCA battery.

Thanks for the input.

I just wanted to add that my battery tender appears to be defective in that the light doesn't always go green after a day or so of charging. But if I jiggle the cables or remove them and re-attach them the light will go green! Then when I reconnect the car's cable the battery appears to be fully charged and my Vette will turn right over.
So All I'm saying is that that I can't trust the red light on my charger that indicates the battery requires more charging time. Partially defeats the purpose of the little bugger.

Spend the $30.00 or so,and get a new tender.

Interesting to see this thread on the first page. I'm wondering the same thing.

6 weeks ago, it went completely dead after I left it sitting in an airport parking lot for 4 days. Got a jump and drove it for an hour before getting home and it seemed to be fine ever since.

But now it just sat for less than 48 hours and went dead again. I didn't leave the lights on, and confirmed the radar detector was unplugged. :crazy2:

Yesterday morning, I removed the battery from the car and put it on my battery tender jr.

Here I am 24 hours later and it's still got a solid red light. The jr model only puts out 750ma. So I guess it will need another 24 hours at least.

O'Reilly's has a battery tender power charger that puts out 5amps but it costs more than a new battery. I guess I will tough it out and charge with what I've got. Then go down and have the battery load tested and maybe check the alternator.


edit: got sick of waiting, bought an 8amp Schumacher charger at Walmart for $37. Hooked up for barely 2 hours and it's already done. :)