Battery charger for depleted battery

Muse

Lifer
Jul 11, 2001
39,076
9,099
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I think around 3 times (including last week) I've had to bring my dead (depleted) battery to O'Reilly to charge it (left lights on). They put it in a device that puts a full charge on it in about an hour. To do this I have to:

Remove battery
Put it in my bicycle's rear basket and ride ~3+ miles to the store, hope no one has gotten there before me
wait an hour
ride home
Replace in car

I have a trickle charger to keep battery topped up (sometimes I don't drive the car for several weeks or more). I have a stronger one that I got at Kragen, but it's not strong enough to charge a depleted battery (last week it was at under 5v).

1. How much would it cost to get a charger that would restore charge on a depleted battery?

2. Would this do a better job than the zapper at O'Reilly? I wonder if charging that fast is bad for the battery.

3. The charge on the battery now is over 13v according to my mulitimeter. It's never over 12.68v or so normally, usually less. Is that bad? I haven't driven the car since O'Reilly charged the battery.
 

LTC8K6

Lifer
Mar 10, 2004
28,520
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It's not good to kill the battery. It's also not good to charge it really fast.

You have probably shortened the life of the battery with these cycles.

You may need a "dumb" charger to charge a battery that is very low.

Smart chargers may not even try if the battery is very low.

The problem is that a dumb charger can overcharge if left unattended.

Automatic, but not smart, I think:
http://www.northerntool.com/shop/tools/product_200331937_200331937

Totally dumb:
http://www.northerntool.com/shop/tools/product_200334443_200334443
 

Muse

Lifer
Jul 11, 2001
39,076
9,099
136
What is the voltage reading while starting the engine? How old is the battery? Have you tested parasitic battery drain?
I can't tell. If I'm starting it I can't get a reading with the multimeter.

The battery is almost new, bought Jan. 7 of this year, Everlast brand at Walmart.

This is the only time this battery has been drained. I brought it over for a charge the same day it happened, within 2 hours of when I realized it had happened (alarm went off, muted).
 

Muse

Lifer
Jul 11, 2001
39,076
9,099
136
It's not good to kill the battery. It's also not good to charge it really fast.

You have probably shortened the life of the battery with these cycles.

You may need a "dumb" charger to charge a battery that is very low.

Smart chargers may not even try if the battery is very low.

The problem is that a dumb charger can overcharge if left unattended.

Automatic, but not smart, I think:
http://www.northerntool.com/shop/tools/product_200331937_200331937

Totally dumb:
http://www.northerntool.com/shop/tools/product_200334443_200334443
I suppose a combination would be the thing... start with the dumb charger, finish with a smart charger.
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
I think the automatic charger is the ticket. It will try to charge a deeply discharged battery, and it will not overcharge it if left unattended.
 

boomerang

Lifer
Jun 19, 2000
18,883
641
126
They don't make the model I have anymore but the comparable model kept the battery in my generator alive and kicking for 10 years to the month. Bought, April 2004, died April 2014.

What clued me in was that the indicator light went from green to red. Sure enough, next time I needed the generator, the battery was too weak to turn it over.

http://batterytender.com/products/automotive/battery-tenderr-junior-high-efficiency.html

Plug it in when you park the car and all you'll have to do is to remember to unplug it before you drive it next.
 

RLGL

Platinum Member
Jan 8, 2013
2,104
314
126
A smart charger needs to see an amount of voltage in the battery to recharge it. the amount depends on the charger
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
If he could remember to plug in a maintainer, he wouldn't forget to turn his lights off...

He has a maintainer already.

He needs something to rescue his battery when he leaves his lights on.
 

bryanl

Golden Member
Oct 15, 2006
1,157
8
81
Measure across the battery terminals while the engine runs fast. Be sure the car is in park or neutral and that the parking brake is set. Many foolish people do not use the parking brake, which is not to imply you're a fool. Less than 13V indicates a charging problem (alternator, voltage regulator, wiring, connections), but between 13-15V is normal.

Walmart warranties include free replacement during the first 1-3 years, depending on the particular battery.
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
There's no indication whatsoever of any charging problem with the car.

OP is questioning if they overcharged his battery at O'Reilly because it measures over 13V instead of it's usual 12.68V.

If he wants to check the battery with a multimeter, he will need to put some kind of decent load on it, such as turning on the headlights and the electric defogger, without starting the engine, and then measure the battery voltage.

It's hard to check cranking voltage at the battery without a friend. It can be done if you can attach the meter leads safely and prop the meter up where you can see it when cranking.

I suspect the over 13V is just residual surface charge from the very fast O'Reilly charge, and everything is fine.
 
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tortillasoup

Golden Member
Jan 12, 2011
1,977
4
81
I agree with LTC8K6. Also if you want a good maintainer/charger, I recommend The Battery Minder 1500. It pulse desulfates while charging/maintaining.
 

NuroMancer

Golden Member
Nov 8, 2004
1,684
1
76
I think around 3 times (including last week) I've had to bring my dead (depleted) battery to O'Reilly to charge it (left lights on). They put it in a device that puts a full charge on it in about an hour. To do this I have to:

Remove battery
Put it in my bicycle's rear basket and ride ~3+ miles to the store, hope no one has gotten there before me
wait an hour
ride home
Replace in car

I have a trickle charger to keep battery topped up (sometimes I don't drive the car for several weeks or more). I have a stronger one that I got at Kragen, but it's not strong enough to charge a depleted battery (last week it was at under 5v).

1. How much would it cost to get a charger that would restore charge on a depleted battery?

2. Would this do a better job than the zapper at O'Reilly? I wonder if charging that fast is bad for the battery.

3. The charge on the battery now is over 13v according to my mulitimeter. It's never over 12.68v or so normally, usually less. Is that bad? I haven't driven the car since O'Reilly charged the battery.

If it was right after they recharged your battery, then a phenomenon known as "surface charge" will cause the battery voltage to be higher than normal. To get rid of it either:

1. Allow the battery to sit for six hours with no load or charger connected
2. Apply a 25 amp load for three minutes and wait five minutes

See all the other good advise in this thread otherwise.
 

Muse

Lifer
Jul 11, 2001
39,076
9,099
136
I agree with LTC8K6. Also if you want a good maintainer/charger, I recommend The Battery Minder 1500. It pulse desulfates while charging/maintaining.
Thank you. I just went to Amazon's page for the Battery Minder 1500. It's 1.5amp. The second question put forth on that page was "Will this charge a 12V battery that is DEAD? (<2v)?" There are several answers, not all agreeing. Some say yes, others no (well, not that simple). Seems like it would be possible and maybe not a bad way to go, especially if there's no big hurry. It would seem to be better to use higher amp charger, for at least the initial charger.

I have a Schumacher Model SE-1-125, also a 1.5amp charger, but the instructions make no mention of desulfating, so I assume it doesn't do that. I paid almost $30 for it around 10 years ago at Kragen (Amazon's selling the Battery Minder 1500 for $50).

The Schumacher's instructions say it can charge a battery that has at least 2v. It goes on to say that "for large automotive or marine battery which are deeply discharged, it is recommended to recharge first with a larger charger (such as a 10 amp) then use the SE-1-125 to maintain the charge level of the battery."

To follow that recommendation if I found my battery dead in the driveway because I'd left the lights on would mean I'd either have to buy a 10amp charger or haul it over to O'Reilly with my bicycle.

So,

1. Get a 10amp and charge the "dead" battery with that
2. Get the Battery Minder 1500 and charge the "dead" battery with that
3. Use the Schumacher and charge the "dead" battery with that
4. Get a 10amp and get the Battery Minder 1500

:confused:

Edit: Actually, this page suggests with a simple "Yes" answer that the Schumacher SE-1-125 charger does desulfate. True or not, I don't know...
 
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LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
Get a 10A automatic charger, not smart, and use it with your Schumacher maintainer.

Even if the small maintainers will try to charge a dead battery, they are going to take forever to do it. The little Schumacher will try down to 1 volt.

You need the bigger charger to get the dead battery back in a reasonable time.
 

RagingBITCH

Lifer
Sep 27, 2003
17,618
2
76
EverStart (not last) comes with a 1 year free replacement. (Some have up to 3 years) Why not take it in to have it replaced under warranty vs dealing with this manual headache and charging?
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
EverStart (not last) comes with a 1 year free replacement. (Some have up to 3 years) Why not take it in to have it replaced under warranty vs dealing with this manual headache and charging?

There's no indication of any problem with the battery.
 

tortillasoup

Golden Member
Jan 12, 2011
1,977
4
81
Thank you. I just went to Amazon's page for the Battery Minder 1500. It's 1.5amp. The second question put forth on that page was "Will this charge a 12V battery that is DEAD? (<2v)?" There are several answers, not all agreeing. Some say yes, others no (well, not that simple). Seems like it would be possible and maybe not a bad way to go, especially if there's no big hurry. It would seem to be better to use higher amp charger, for at least the initial charger.

I have a Schumacher Model SE-1-125, also a 1.5amp charger, but the instructions make no mention of desulfating, so I assume it doesn't do that. I paid almost $30 for it around 10 years ago at Kragen (Amazon's selling the Battery Minder 1500 for $50).

The Schumacher's instructions say it can charge a battery that has at least 2v. It goes on to say that "for large automotive or marine battery which are deeply discharged, it is recommended to recharge first with a larger charger (such as a 10 amp) then use the SE-1-125 to maintain the charge level of the battery."

To follow that recommendation if I found my battery dead in the driveway because I'd left the lights on would mean I'd either have to buy a 10amp charger or haul it over to O'Reilly with my bicycle.

So,

1. Get a 10amp and charge the "dead" battery with that
2. Get the Battery Minder 1500 and charge the "dead" battery with that
3. Use the Schumacher and charge the "dead" battery with that
4. Get a 10amp and get the Battery Minder 1500

:confused:

Edit: Actually, this page suggests with a simple "Yes" answer that the Schumacher SE-1-125 charger does desulfate. True or not, I don't know...
The battery minder is a better charger... The question about charging a battery with super low voltage is simple to answer. If the voltage is less than 3v, the charger on its own will not charge it... However the fix for that is relatively simple. All you have to do is get a jumper cable in parallel with that of a battery with higher voltage, connect them until the battery being charged' voltage is higher than 3V (I recommend trying at least 6V) then you can attach the charger.

A smart charger is the way to go and as somebody who has tried a wide variety of chargers, I can only recommend the batteryminder.

BTW, I don't recommend high amp charges on severely discharged batteries as batteries will not accept high amperage charges when severely discharged. The charger will probably/hopefully error if presented with such a situation. In fact, if you bought a batteryminder 12248 charger which is a 2-4-8 amp charger, if you're charging below like 11v, the charger even if you select 8amps will charge at like .5 amps or some really low amount and slowly ramp up the amperage once it reaches like 11amps. This is acceptable because the bulk of a 12v Lead Acid battery's capacity (i.e charging time) will be from like 11v to 12.7V or 13.1 for an AGM battery.
 
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Muse

Lifer
Jul 11, 2001
39,076
9,099
136
There's no indication of any problem with the battery.
Exactly.
Or, quit leaving your lights on...
Damned good idea! I resolved to do that last time this happened. But alas, it did happen again. I did notice (vaguely in my clouded hurry that day) what seemed to me a strange beeping, but dismissed it was a seatbelt warning. In retrospect, not so...

Thanks to everyone who has posted here!
 
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Muse

Lifer
Jul 11, 2001
39,076
9,099
136
Or, quit leaving your lights on...
I did this yesterday, driving home in the late afternoon. It was very cloudy, unusually dark, off and on drizzle and almost all the cars had some kind of headlights on... but not me! I didn't want to chance leaving them on! :eek:

Can anyone venture to guess how long a 1.5amp charger would take to get a 12v car battery from ~5v (i.e. depleted) up to somewhere near capacity (i.e. ~12.5v)?
 
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LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
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I did this yesterday, driving home in the late afternoon. It was very cloudy, unusually dark, off and on drizzle and almost all the cars had some kind of headlights on... but not me! I didn't want to chance leaving them on! :eek:

Can anyone venture to guess how long a 1.5amp charger would take to get a 12v car battery from ~5v (i.e. depleted) up to somewhere near capacity (i.e. ~12.5v)?

24 hours?

Schumacher makes a 3A version...that might be what you need. It will charge the battery faster, but perform the same maintenance function.

http://www.amazon.com/Schumacher-SC-.../dp/B000H90XEW
 

tortillasoup

Golden Member
Jan 12, 2011
1,977
4
81
I did this yesterday, driving home in the late afternoon. It was very cloudy, unusually dark, off and on drizzle and almost all the cars had some kind of headlights on... but not me! I didn't want to chance leaving them on! :eek:

Can anyone venture to guess how long a 1.5amp charger would take to get a 12v car battery from ~5v (i.e. depleted) up to somewhere near capacity (i.e. ~12.5v)?

Expect at least 2 days. Even with a Batteryminder 12248, lead acid batteries that are severely discharged typically will not accept a higher charging rate and will error out the battery charger if you attempt it which is why the slow and steady will win the race. High amp chargers work better when the battery is in its RESTING voltage (no surface charge) 11.8v+ which is where the bulk of the capacity is.
 

Mandres

Senior member
Jun 8, 2011
944
58
91
I hate my automatic trickle charger/battery tender. It will not even try to charge a dead battery - I have to trick it by hooking up a second voltage source for an hour or two until the dead battery has enough juice to start the flow on its own.

Guess I need to shell out for a "dumb" charger, but why the hell are they more expensive than the ones with control circuity?
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
I hate my automatic trickle charger/battery tender. It will not even try to charge a dead battery - I have to trick it by hooking up a second voltage source for an hour or two until the dead battery has enough juice to start the flow on its own.

Guess I need to shell out for a "dumb" charger, but why the hell are they more expensive than the ones with control circuity?

Solid state is cheaper?