can a trickle or battery tender charger properly charge a car battery?

[holden j caufield]

My gf left her fog lights on and the car wouldn't start in the morning, multimeter read something less than 10v. Got it jump started by AAA and their machine says it was 10.23v and 134 CCA. She doesn't drive very far so I thought I'd put a trickle charger on it for a day. After 20 hours the battery reads 12.7v on my multimeter but it won't start. AAA came out again and their machine said it was now only 10.6v. The battery is about 1.25 years old on a 2008/09 Nissan Sentra. Time for a new battery or do I need to leave it on the trickle charger for longer? I'm using this battery tender not really a charger but it's all I have right now.

http://www.amazon.com/Battery-Tender...dp/B000CITK8S/

 

[desy]

I'd have thought 20 hrs would have done it, however that is a smart charger and should indicate by LED if its good to go.
I can't see in what world your MM would be out 2V and unless that battery froze it should bounce back from being run down.
double check your connections and not just on the battery where they run back to.

 

[Jimzz]

Just take the battery out and have it tested. Most major parts stores will charge and test for free.

 

[jagec]

It's dead, Jim.

A lead-acid battery at 10.5V resting is COMPLETELY drained, and if left in that state for any appreciable amount of time will sulfate, leading to a permanent loss of capacity. You can try doing a high-amp recharge to stir up the electrolyte and reduce the time that it sits at low voltages, but the damage is probably done already.

The trickle charger won't cut it. They're only designed for maintaining already-charged batteries and fighting off the dreaded sulfates.

 

[bryanl]

Battery Tender Junior is rated for 0.75A, but a dead car battery needs 75 amp-hours, meaning an additional 80 hours of charging was required. Immediately after a full charge, the battery should read over 13V.

 

[MrPickins]

Was she not able to charge it with the alternator?

 

[Gillbot]

They can but will take more than a day.

 

[LTC8K6]

You need a real battery charger, really.

Or, get it jump started and drive it for 30 minutes.

The battery has had it's overall life shortened, but it's probably still okay if you fully charge it.

AAA is probably using a more accurate load tester versus the multimeter.

 

[holden j caufield]

been two days and so far it's still charging, going very slow. Her drive is too short for the alternator to charge it. Would

 

[SpatiallyAware]

A tiny <1a charger isn't going to do jack for a totally dead battery. It will take a week, if not longer, if at all.


How old is the battery? What caused it to initially hit 10v?

If the battery is older than 4 years just replace it. Particularly on your SO's car. Are you comfortable with her trying to get a jump at some random parking lot??

 

[holden j caufield]

I'm wondering usually they have sticker that has a date on it. This one says E27, means it's made in May of 2012?

She left the fog lights on. I'm not sure how long that has been, she didn't even know she had a fog light switch. But I think max 1 day the fog light was on.

 

[LTC8K6]

I wouldn't bet on the trickle charger, especially since you tried to crank it. It must be very low.

I would get it jump started and then take it on a 30 minute trip, then put it on the trickle charger to top it off overnight.

 

[tortillasoup]

A trickle charger will work just fine folks. OP, just keep charging. It's mathematically possible to figure out how long it will take to charge the battery. Just figure out the AH of the battery, the amps of the charger and then you'll know. As a baseline, most batteries are about 50AH, so a 1AH charger will take at least 2 days assuming 100% efficiency which batteries are NOT, more like 50% efficient at charging! (Lead acid are horridly inefficient at charging).

The battery should be "use-ably charged" within 2 days and fully charged in 4 days with a trickle charger.

FYI using a trickle charger on a deeply discharged battery is actually the safest, best way to recover a battery. Any other way will destroy the battery.

 

[Zenmervolt]

FYI using a trickle charger on a deeply discharged battery is actually the safest, best way to recover a battery. Any other way will destroy the battery.

A good bench charger that has microprocessor control is not going to "destroy" a deeply discharged battery. While I agree that zapping a marginal battery with a 60-amp charge rate from a shop charger isn't the best idea in the world there's no need to drop all the way down to a sub-1-amp trickle charger. A moderate 15- to 20-amp charge rate will be just fine in the vast majority of cases as long as the charger is intelligent. And I've yet to see a need to drop below the 2-amp "slow charge" rate that is near-universal on bench chargers.

The little "trickle chargers" (usually actually float chargers) use very low charge rates because they can't dissipate heat as effectively as a full bench charger due to their size. This isn't an issue because they're designed to stay hooked up to a car/motorcycle/ATV/boat/etc for an entire season for simple maintenance and are never really intended to fully charge a battery.

ZV

 

[franksta]

I have the exact charger you posted the link to and it took several days for the light to go green. This was on the battery for my old aircooled beetle. Obviously not the fastest way to go but it does work.

 

[LTC8K6]

FYI using a trickle charger on a deeply discharged battery is actually the safest, best way to recover a battery. Any other way will destroy the battery.

Then it must be destroyed, because it was jump started at least once while it was very deeply discharged...that is certainly a fast and dirty recharge.

In fact, it's very common to rapidly recharge deeply discharged LA batteries with "dumb" chargers or the alternator. I'm sure it shortens their overall life, but I wouldn't use the term destroy.

 

[tortillasoup]

A good bench charger that has microprocessor control is not going to "destroy" a deeply discharged battery. While I agree that zapping a marginal battery with a 60-amp charge rate from a shop charger isn't the best idea in the world there's no need to drop all the way down to a sub-1-amp trickle charger. A moderate 15- to 20-amp charge rate will be just fine in the vast majority of cases as long as the charger is intelligent. And I've yet to see a need to drop below the 2-amp "slow charge" rate that is near-universal on bench chargers.

The little "trickle chargers" (usually actually float chargers) use very low charge rates because they can't dissipate heat as effectively as a full bench charger due to their size. This isn't an issue because they're designed to stay hooked up to a car/motorcycle/ATV/boat/etc for an entire season for simple maintenance and are never really intended to fully charge a battery.

ZV

I doubt OP has a "Battery Minder" battery charger which will actually trickle charge until about 11.9v before charging @ a faster rate. Also charging @ a rate of 20a/h is way too fast as most lead acid batteries right on their sticker specify to not charge @ a rate higher than 5a-10a/h anyway. Yes people DO like to charge faster but what happens is charging too quickly can/will damage the battery. I'm very very experienced with lead acid batteries.

 

[LTC8K6]

Op has a Battery Tender Junior, which does have different charge modes and a 3/4A max output.

 

[Zenmervolt]

I doubt OP has a "Battery Minder" battery charger which will actually trickle charge until about 11.9v before charging @ a faster rate. Also charging @ a rate of 20a/h is way too fast as most lead acid batteries right on their sticker specify to not charge @ a rate higher than 5a-10a/h anyway. Yes people DO like to charge faster but what happens is charging too quickly can/will damage the battery. I'm very very experienced with lead acid batteries.

Actually, the stickers tend to limit charging rate to C/3, or capacity over 3. So if you have a 50 Ah battery, the maximum recommended charge rate is 50/3 amps, or 16.67 amps.

The reason for this limit, however, is not for preserving the maximum number of cycles the battery can withstand, but rather to avoid rupturing the sealed casing if you happen to overcharge the battery. Even "sealed" batteries create gasses when they are charged (and especially when over-charged). At a charge rate of C/3 or less, the amount of gassing on overchage is small enough that the battery will not need to vent and the gas will be able to recombine with the electrolyte. At higher charge rates, however, the battery will begin to vent, or, if there is a defect in the vent valve, the battery may even rupture. In older non-sealed batteries, (and in "sealed" batteries that have vented) the electrolyte will begin to boil off, reducing the battery's capacity.

However, on modern "smart" chargers the microprocessor monitoring the charge rate will intelligently adjust the actual charge rate and avoid this problem. Even if you select a 20-amp charge rate on a modern microprocessor-controlled charger, the charger will still drop the charge rate as the battery nears a 100% SOC and will even go into a very low amperage float mode once charging has been completed.

The advice against faster charge rates comes from the days when chargers simply applied a fixed charge rate and had no ability to monitor the battery's SOC. So, to avoid the potential for a user to damage the battery through overcharging, they specified a maximum rate that was below the point where moderate over-charging would cause significant damage.

While slower charge rates will always maximize service life, an isolated fast charge once or twice during a battery's 6-10 year service life is not going to be an issue.

ZV

 

[RagingBITCH]

I guess the easy question to ask here is, where did she buy it from? Even the "base" level batteries have at least a 2-3 year replacement, and anything after that is pro-rated. If it's only slightly over a year old take it back to wherever she got it and have them swap it out with a new one.

 

[brainhulk]

I have the same battery charger as the op. It worked for one battery of mine but not another. And I concur it is slow