So I accidentally left my lights on for a couple hours today in the freezing cold in my 02 honda accord. I didn't realise this until I went to start the car and nothing happened. The starter did not click, the door locks didn't work, and the radio stations all got reset. So I called aaa to get someone to jump start my vehicle. After waiting a 1/2 hour with everything off I decided to try and start it again. To my surprise it came right to life. I am surprised the battery regained enough power to start the car and show enough voltage to the ecm to start it. I did not know that a battery could regain itself like that. Has anyone ever had that happen?
Left my lights on and battery died.
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Nick1994
$100 site donor 2024
Do you have a battery charger? If so, hook it up and charge that battery.
Yep, recharge battery at 2A charge rate.
I would drive it for an hour and you should be fine. But to answer your question, nope havent had it happen to me.
gathermewool
Site Donor 2023
Originally Posted By: Mr Nice
Yep, recharge battery at 2A charge rate.
Why 2A?
OP, same thing happened to me recently:
Gathermewool killed his battery, too
I charged it for an extended period soon after finding it dead and there are not any apparent issues.
Yep, recharge battery at 2A charge rate.
Why 2A?
OP, same thing happened to me recently:
Gathermewool killed his battery, too
I charged it for an extended period soon after finding it dead and there are not any apparent issues.
Originally Posted By: Rolla07
I would drive it for an hour and you should be fine. But to answer your question, nope havent had it happen to me.
As long as premature battery death is not a concern.
I would drive it for an hour and you should be fine. But to answer your question, nope havent had it happen to me.
As long as premature battery death is not a concern.
Originally Posted By: gathermewool
Originally Posted By: Mr Nice
Yep, recharge battery at 2A charge rate.
Why 2A?
OP, same thing happened to me recently:
Gathermewool killed his battery, too
.
I charged it for an extended period soon after finding it dead and there are not any apparent issues.
It is gentler on the battery and should prolong battery charge and life. If you have the option, choose this.
Google will let you get into the technicals if you want them.
Originally Posted By: Mr Nice
Yep, recharge battery at 2A charge rate.
Why 2A?
OP, same thing happened to me recently:
Gathermewool killed his battery, too
.
I charged it for an extended period soon after finding it dead and there are not any apparent issues.
It is gentler on the battery and should prolong battery charge and life. If you have the option, choose this.
Google will let you get into the technicals if you want them.
Sounds like it had some sort of fail safe that shut off the system before it drained it completely. I would recharge it but not at 2 amps, I would use between 6-10 amps if I had the option.
My charger has a 2/10/20 setting, I think the 20 amp setting is too aggressive for such small batteries unless they are agm... Good deep cycle agm can accept huge currents, like 40 amps for automotive deep cycle
My charger has a 2/10/20 setting, I think the 20 amp setting is too aggressive for such small batteries unless they are agm... Good deep cycle agm can accept huge currents, like 40 amps for automotive deep cycle
This is a well known phenomenon. The battery was not completely discharged, but the surface charge that starts the engine was depleted. With some time, a deeper charge migrated to the surface, and this was enough to start the engine.
1/3 to 1/2 your potential battery life is now gone.
You need to recharge it with a good 10 amp charger, then put on a trickle charger for about a week, so you can replace that deeper charge too.
If it is a flooded battery check the water level. And, don't do it again.
Rod
1/3 to 1/2 your potential battery life is now gone.
You need to recharge it with a good 10 amp charger, then put on a trickle charger for about a week, so you can replace that deeper charge too.
If it is a flooded battery check the water level. And, don't do it again.
Rod
Originally Posted By: dishdude
I just wouldn't want my alternator charging the battery from dead, they aren't designed to do that - just to top it off.
Yes charging your battery with your alternator is a good way to blow out your alternator. If it is weak it is easy to kill one.
It used to make me angry to watch the other mechanics kill a battery and just throw a jump box on it to get it started. You are doing your customer no favors. I would use a auto trickle charger on pretty much every car I worked on if I was going to have the door open and the key on to do any diagnostics. I rarely ever had to jump anything I was working on. It saved me time since I pretty much kept the charger on my bench.
Now I work on industrial batteries and I don't think much of a battery unless it weighs over 1000 lbs.
As far as charge rates go. Well it varies for a lead acid battery based on a six hour discharge rate
Most autos are 20 hour discharge rate. Start rate should be 16-25a/100 finish should be 5/100
You want the 5% finish on the end to properly mix the electrolyte. If it is too high it burns it out. Too low it does not mix properly and causes it to sulphate.
I just wouldn't want my alternator charging the battery from dead, they aren't designed to do that - just to top it off.
Yes charging your battery with your alternator is a good way to blow out your alternator. If it is weak it is easy to kill one.
It used to make me angry to watch the other mechanics kill a battery and just throw a jump box on it to get it started. You are doing your customer no favors. I would use a auto trickle charger on pretty much every car I worked on if I was going to have the door open and the key on to do any diagnostics. I rarely ever had to jump anything I was working on. It saved me time since I pretty much kept the charger on my bench.
Now I work on industrial batteries and I don't think much of a battery unless it weighs over 1000 lbs.
As far as charge rates go. Well it varies for a lead acid battery based on a six hour discharge rate
Most autos are 20 hour discharge rate. Start rate should be 16-25a/100 finish should be 5/100
You want the 5% finish on the end to properly mix the electrolyte. If it is too high it burns it out. Too low it does not mix properly and causes it to sulphate.
When this occurred I was almost 90 miles from home. I did not stick it on a battery charger because I drove 1.5 hours home almost all highway so I figured that that would be enough to help it recharge. Should I stick it on my battery charger today?
I'd still put a charger on it for the reasons already outlined. However, you did what you had to in your situation, and I would have done much the same. The alternator and the highway run isn't the ideal solution, but what should you have done, rented a hotel room, bought a charger, and plugged it in and waited?
Originally Posted By: ragtoplvr
This is a well known phenomenon. The battery was not completely discharged, but the surface charge that starts the engine was depleted. With some time, a deeper charge migrated to the surface, and this was enough to start the engine.
1/3 to 1/2 your potential battery life is now gone.
You need to recharge it with a good 10 amp charger, then put on a trickle charger for about a week, so you can replace that deeper charge too.
If it is a flooded battery check the water level. And, don't do it again.
Rod
Never heard of this before, but I trust your assessment. I would have chalked it up to the battery gods looking down favorably on the OP and granting him a miracle bolt of electric energy to get him started!
This is a well known phenomenon. The battery was not completely discharged, but the surface charge that starts the engine was depleted. With some time, a deeper charge migrated to the surface, and this was enough to start the engine.
1/3 to 1/2 your potential battery life is now gone.
You need to recharge it with a good 10 amp charger, then put on a trickle charger for about a week, so you can replace that deeper charge too.
If it is a flooded battery check the water level. And, don't do it again.
Rod
Never heard of this before, but I trust your assessment. I would have chalked it up to the battery gods looking down favorably on the OP and granting him a miracle bolt of electric energy to get him started!
A lot of times vehicles have "battery savers" that will cut the battery out once voltage gets too low (from headlights), etc.
I found this out when the alternator went out on my Jeep and I had to drive it until it died. It had 9 volts, but when I would try to put my windows up (it was 40 degrees and rainy), the battery saver would activate and cut power.
I found this out when the alternator went out on my Jeep and I had to drive it until it died. It had 9 volts, but when I would try to put my windows up (it was 40 degrees and rainy), the battery saver would activate and cut power.
I've had this happen a few times over the years. It seems that if a good battery is killed, it can recover enough juice while sitting to start the car (or in my case, truck). If the battery is weak or old it is less likely.
I have been hearing that bit about not using an alternator to charge a battery a lot lately. I had never heard that before and have charged many batteries from nearly dead using the alternator - I have not had an alternator fail in one of my cars since '86. I wonder how that is harder on the alternator than driving with the headlights, AC, wipers, defrosters, etc. on?
My wife has had alternator mechnical failures in her last two cars, but no dead batteries, so not a valid data point.
It seems with all the PCM/ECM charge management in place on current cars, they should be able to maintain a safe balance.
I have been hearing that bit about not using an alternator to charge a battery a lot lately. I had never heard that before and have charged many batteries from nearly dead using the alternator - I have not had an alternator fail in one of my cars since '86. I wonder how that is harder on the alternator than driving with the headlights, AC, wipers, defrosters, etc. on?
My wife has had alternator mechnical failures in her last two cars, but no dead batteries, so not a valid data point.
It seems with all the PCM/ECM charge management in place on current cars, they should be able to maintain a safe balance.
I have a fairly simple charger, but it's not bad.
GYS floating 3A, IUoU. I can select the Uo to be 14.3v or 14.8v
I-phase the voltage goes up to 14.3v, Uo either 14.3 or 14.8v, then the last phase is 13.8v.
It won't start charging if the battery has less than 4V output though.
regarding alternators: did you notice the output doubled to tripled over the last decades, but the size didn't change? they're more prone to overheating if used at their rated capacity (and the engine being shut down while they still were)
GYS floating 3A, IUoU. I can select the Uo to be 14.3v or 14.8v
I-phase the voltage goes up to 14.3v, Uo either 14.3 or 14.8v, then the last phase is 13.8v.
It won't start charging if the battery has less than 4V output though.
regarding alternators: did you notice the output doubled to tripled over the last decades, but the size didn't change? they're more prone to overheating if used at their rated capacity (and the engine being shut down while they still were)
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