Charging battery with battery charger vs jump starting and running the car

Question

Got a 1998 Toyota Camry that has an empty battery and am wondering what the best course of action is.

I have a battery charger that I am thinking of using but it's currently inconvenient to do.

My question is: If I just jump start the car and run it for long enough to charge the battery, is this the same as charging the battery with a battery charger? Or would there be benefit to using the battery charger?

I plan on running everyday to keep the battery charged.

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Added:

The car had been unregistered for a while and wasn't driven for an extended period (~3 months) which has lead to the battery running flat. I am not 100% on the age of the battery but it doesn't "look" that old but I know that may not matter.

At this point I know the car needs a new battery eventually, but to get it registered it needs to be seen by a mechanic and have a few things done and checked. Until then just want to get the car running again to keep it in good condition.

Answer 1

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 it empty because you yesterday forgot the lights on?

The correct course of action depends on the reason for it being empty.

If the battery is good but you just forgot the lights on, and it has been empty only for a short duration of time (lead-acid batteries don't like extended deep discharge), then go ahead and jump start the car. That's the fastest way. You have to be careful when driving the car afterwards because if you accidentally misuse the clutch and cause the engine to stall, there's a risk you can't start it again. But with a little bit of care, you can drive it.

If the battery is empty because it is old and dying, do not jump start it! The problem is that when jump starting, it is actually the donor battery providing charge. When you disconnect the donor vehicle, the only good battery in the electrical system goes away. The dying old battery in the recipient car can't act as a buffer for the electrical system. The alternator can then produce voltage spikes, destroying expensive electronic equipment all around the car. The newer the recipient car is, the more damage you will see. I would say 1998 car has enough electronics that you don't want to destroy all of them.

So with an old and dying battery, you can try to see whether charging will remedy the situation. You can charge it slowly with a battery charger or rapidly from a donor car with jump start leads, but in that case don't turn the recipient car engine on. Then check to see whether the old battery is able to start the engine (with charger / jump start leads disconnected). If not, it's time to purchase a new battery. If it can start the engine, keep an eye of the situation and estimate when you need the new battery, if you need it at all.

If you forgot the lights on, and then left the battery sit for a week or two not bothering to fix the situation, then the health of the battery is unknown -- on one hand, the battery was good before the event, but on the other hand, lead acid batteries don't like extended deep discharge. So it is possible the deep discharge has damaged the battery. It's always safer to charge and then try starting than to jump start.

Answer 2

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 the battery and make sure this doesn’t happen again.

However if you want to try to charge it, it will be less stressful for the battery to be slowly charged by a battery charger than getting a very quick charge from a jump start. If there is a fault inside the battery, connecting it to a fully charged battery could cause a very large current to flow, causing danger to yourself.

For safety, it is best to try trickle charging it in an open space with good ventilation.

I would still recommend replacement, because this one is likely to let you down soon.

Answer 3

It's better to charge it with a normal several amp charger in this case than to fast charge it with the car's alternator. It may also take a bit of time for the car's alternator to get it started charging at the beginning of the cycle and to top it off at the end which will waste gas. There may be a cell imbalance in the battery which will take much longer to correct with a 14.4V alternator than it will with a 15 Volt traditional unregulated car battery charger.

I suggest jumping it and driving it closer to the outlet and then charging it for a day with the normal charger. Or take the battery out and carry it to the charger. Charging it at 15 Volts will be an equalization charge that it probably needs after sitting dead.

I'm currently dealing with this issue where the dome light brought the battery down to zero for a month and running the car for 2 hours didn't charge the battery anywhere near full. I know because the battery is at 12.4 Volts but won't crank the engine after a couple weeks sitting. My battery may have a weak cell that is self discharging faster than the others.