25
votes
Accepted
Can one slightly charge a dead car battery with a portable battery jump kit?
As Miracle Max would say, there's two kinds of dead batteries, and there's a big difference between them.
Mostly Dead
This is the most common kind of dead battery. Let's say your battery is rated for ...
- 376
22
votes
Accepted
Charging battery with battery charger vs jump starting and running the car
Got a 1998 Toyota Camry that has an empty battery and am wondering what the best course of action is.
Why is it empty?
Is it empty because the battery is old and dying and won't hold capacity?
Or is ...
- 14.4k
18
votes
Accepted
Is charging my engine battery like this bad?
Use the jumper battery to start the engine, then disconnect it and leave the engine running (with no current drain such as lights, heater fan, radio, etc). The car should charge its own battery to 80% ...
- 8,652
18
votes
What is more cost effective: re-charging a car battery or replacing it new when it dies?
The cost has been addressed, but there's an underlying question: is the battery dead (i.e. it cannot hold enough charge anymore to start the car), or has it just been discharged?
If it's just been ...
- 4,412
13
votes
Factors Limiting EV Battery Acceptance Rate on DC Fast Chargers
Generically speaking, higher charge rates will heat a pack more quickly than the lower rates. Tesla models are designed and constructed with active cooling as well as appropriate monitoring and charge ...
- 4,330
12
votes
Is charging my engine battery like this bad?
Lead acid type batteries, such as this, like to be charged very slowly. Under 5 amps for many hours would be best. During fast charging the internals overheat and electrolyte can boil. Best to charge ...
- 11.6k
12
votes
Can one slightly charge a dead car battery with a portable battery jump kit?
Those types of chargers are designed to provide short bursts of power to start a car, most do not have a battery charging mode. Once the car is started the alternator will complete charging the ...
- 15.5k
11
votes
2 Volts on Car Battery
Lead sulfate crystals form on the battery plates as the battery discharges. As the battery becomes more discharged the crystals go from being soft and fluffy to much harder. Recharged in time, the ...
- 211
10
votes
Accepted
12V Battery change
IIRC, the Prius has a step down voltage regulator which charges the 12v battery from the main power. I'd bet this system is having an issue and is not charging the battery.
As for the 12v battery. I'...
- 148k
10
votes
Accepted
2 Volts on Car Battery
Since you have a battery which isn't that old (most batteries have about a five year life span), I'd suggest you put it on a charger and try to recharge it. This will allow the battery to come back to ...
- 148k
10
votes
Accepted
How do I keep an idle/unused battery ready for immediate use?
Similar batteries are used for motorcycles, and many people don't use those very often at all. They sit in the garage for months at a time until the weather is just perfect for that 20 minute ride. ...
- 13.3k
10
votes
Is my car battery charger not working?
12.45 to 11.94 in 6 days seems like a significant discharge. You should be able to leave your car for a month or longer and still have enough power to start. At your current discharge rate, I wouldn'...
- 8,433
10
votes
Solar Charging Car Battery through Cigarette Lighter Outlet?
Why don't you connect it to the battery directly?
Do you know, that mechanical contact with metal springs inside lighter plugs is not very reliable? It has relatively big resistance and will be ...
- 211
9
votes
Accepted
Is it safe to charge two batteries off of one alternator?
The most effective way to charge an additional battery from a single alternator is by use to a Split Charging setup.
You can buy kits from various sources and they are common amongst both campers, ...
- 23.4k
9
votes
Is charging my engine battery like this bad?
A @FredWilson says, you need to charge it slowly - either by driving it around or by using a trickle charger. If you can get a trickle charger with a 'maintenance mode', you can leave it permanently ...
- 28.7k
9
votes
Accepted
Is there any advantage to keeping the battery "topped up"?
As long as it is not overcharging your battery, it will increase the useful life of the battery. The reason behind this is, as a battery sits, it loses power. Some of the electrolysis which goes on to ...
- 148k
9
votes
Accepted
Have I fried my alternator through frequent use of an external charger?
It's very unlikely your charger had anything to do with your alternator failure, unless you were running the charger and your engine at the same time, even then I'd expect a charger to cut out as it ...
- 15.5k
8
votes
Accepted
Battery maintainer vs trickle charger
The difference is smarts.
A trickle charger provides a constant current all the time. It does not know whether the battery is charged or discharged.
A battery tender is smart. It will charge the ...
- 16k
8
votes
Car battery dead for a while... now it won't charge?
I'm not going to tell you to try and utilize a battery charger to fix the issue as @MoveMoreCommentsLinkToTop has suggested in the comments, but it has been my experience when a battery has sat for an ...
- 148k
8
votes
What is more cost effective: re-charging a car battery or replacing it new when it dies?
It is nice that some people put complicated math here (which is mostly correct also) but IMHO there was no reason to complicate it so much. As a rule of thumb:
IF battery can be recharged then it is ...
- 1,168
8
votes
Accepted
Would charging a car battery while interior lights are on stop a car from charging or damage it?
It didn't damage your battery or the charging at all. Because:
All batteries in automotive created for simultaneously charging and discharging otherwise your car will not have an alternator in the ...
- 367
8
votes
Factors Limiting EV Battery Acceptance Rate on DC Fast Chargers
One of the issues you face is that the battery capacity is itself one of the limiting factors for the power a battery can take. This is typically referred to as C-rating. That means you can charge a ...
- 181
7
votes
Is it better to hook up a Battery Maintainer for 2 months outside, or take our chances with the battery?
I don't know the exact model of the trickle charger, but would suggest against using it and getting an actual battery tender instead. The difference is, the trickle charger will continue to charge, ...
- 148k
7
votes
Drained battery; imminent explosion?
In a word: nothing.
If a battery is completely dry, or has a lack of electrolyte which doesn't contact the bottom of the charge plates, then nothing will happen. Even if one cell of a 6-cell battery (...
- 148k
7
votes
Solar Charging Car Battery through Cigarette Lighter Outlet?
On my car, the lighter (power) outlet is switched with the ignition, so it is not directly connected to the battery, so you would not be able to charge the battery through that connector if the ...
- 259
7
votes
Charging battery with battery charger vs jump starting and running the car
If the battery is completely flat, then it will have been severely degraded in capacity. Lead acid batteries don’t hold their full charge after going completely flat, so it would be best to replace ...
- 23k
6
votes
Can I charge a 12V car battery with a 16V 1.5A adapter?
I'll preface this by saying, I don't think using a laptop adapter to charge a car battery is the way to go. If it's your only means to get it done, do it at your own risk ... that said:
If you can ...
- 148k
6
votes
Accepted
Can I charge a 12V car battery with a 16V 1.5A adapter?
Your 12v adapter would only be able to raise the battery voltage to 12v, but to charge a car battery fully you would need to raise the voltage to 13.8v. The 16v adapter would raise the voltage too ...
- 23k
6
votes
2 Volts on Car Battery
I don't think you are likely to "put undue stress on the alternator." It is a myth in my opinion that alternators can't handle charging a battery, Alternators are literally motors run in reverse and ...
- 166
6
votes
battery fully discharged, got a jump-start, but what do I do now?
It is very important to charge back the battery as soon as possible.
As per how fast does the alternator charge the battery?, it may take as much as 10 hours or more for the battery to be re-charged ...
- 1,505
Only top scored, non community-wiki answers of a minimum length are eligible