Charging a battery

[nisryus]

So I was reading at another auto forum that when charging a battery, it should be taken out of the car first.

I have always charged my wife's Forester with the terminals attached, and never had problems. Is it really safer to disconnect the terminals and remove the battery from the car first? (Well, I am just lazy and don't want to do more steps.. =P)

 

[Art&Science]

So I was reading at another auto forum that when charging a battery, it should be taken out of the car first.

I have always charged my wife's Forester with the terminals attached, and never had problems. Is it really safer to disconnect the terminals and remove the battery from the car first? (Well, I am just lazy and don't want to do more steps.. =P)

No form of charging that you poses on a residential level requires removing the battery from the vehicle. The amount of amperage that a residential charger puts into the battery is less than the car generates for itself while operating.

Also, nearly all commercial chargers sold in the last 15 years are "smart" chargers and work off of battery voltage, making it nearly an impossibility for the charger to damage the battery or the electrical system of the car.

One other point to mention is that although you may think your battery is "dead" it's actually not and is powering certain electronics on the car, one being the passive anti-theft system which nearly every car has now. So even though the battery cannot start the car, it's still powering this system (and others). If you remove the battery these systems will go un-powered (completely) for many hours and sometimes this can cause syncing issues with keys, FOBS and other features of the system which could (but not definitely) require dealer intervention.

Cliff notes: No, you do not need to remove the battery.

 

[nisryus]

Thanks Art. Going to show this to wife so she won't get too worry too much on how it is being charged.

 

[tortillasoup]

You could always disconnect the battery ground terminal in the car so that you're not fighting the car's parasitic draws while you're charging the battery. The only other reason to charge a battery outside of the car is that occasionally, if a car battery has a dead cell and the person charging the battery isn't aware of it, the battery could short circuit and catch fire. It is this reason that you should be especially careful about using jumper cables as the high current going from a good battery/running car through to a bad battery would be a hazard. But with a simple 5amp "smart" charger, the risk should be very small.

For best longevity, it is recommended by most battery manufacturers not to charge much above 5amps.

 

[nisryus]

Good to know! Thanks TSoup!

 

[razel]

Lots of good info already stated. Continue to keep charging your battery as prior. Only thing to watch for is the electrolyte levels. Keep it topped off.... well just above bottom part of the fill hole. I have a weekend ride that is plugged into a battery minder 5-6 days of the week. Battery needs about 1-2oz of distilled water every 6 months.

 

[Midwayman]

One other point to mention is that although you may think your battery is "dead" it's actually not and is powering certain electronics on the car, one being the passive anti-theft system which nearly every car has now. So even though the battery cannot start the car, it's still powering this system (and others). If you remove the battery these systems will go un-powered (completely) for many hours and sometimes this can cause syncing issues with keys, FOBS and other features of the system which could (but not definitely) require dealer intervention.

So annoying. But this is why you should have a tender on if you have to change a battery.

 

[bryanl]

So I was reading at another auto forum that when charging a battery, it should be taken out of the car first.

I don't see why, unless a battery maintainer is left connected for long periods and is fooled by a car with an electrical system with a high parasitic current draw. Some older cars would draw over 0.1 amp when parked

 

[tortillasoup]

I don't see why, unless a battery maintainer is left connected for long periods and is fooled by a car with an electrical system with a high parasitic current draw. Some older cars would draw over 0.1 amp when parked

The other concern though it may be specious is that the chargers with their pulses might damage the car's electronics. The thing is though, the charger is suppose to be directly off the battery or very close to it, not running through a maze of electrical wiring before getting to the battery. Any and all pulses should and would be directed to the battery itself which works like a capacitor anyway.

 

[boomerang]

I had my car on a battery tender for 4 months over the winter with the battery connected. No ill effects.

 

[bryanl]

The other concern though it may be specious is that the chargers with their pulses might damage the car's electronics. The thing is though, the charger is suppose to be directly off the battery or very close to it, not running through a maze of electrical wiring before getting to the battery. Any and all pulses should and would be directed to the battery itself which works like a capacitor anyway.

I've heard of pulse chargers that put out 50V peak pulses or even negative pulses (to shake bubbles loose from plates), and I'd definitely want the battery disconnected when using one of those, but even desulfator chargers that feed up to 16-17V are safe for use with cars.

 

[razel]

It's beyond time to drop the FUD of pulse chargers. Just buy a good one. Not expensive, GOOD. No issues at all the past 7 years with a $35 Battery Minder (pulse charger/maintainer) on my 2002 weekend ride. It lives 5/7ths of it's life plugged in and pulsing all those years.

 

[tortillasoup]

I've heard of pulse chargers that put out 50V peak pulses or even negative pulses (to shake bubbles loose from plates), and I'd definitely want the battery disconnected when using one of those, but even desulfator chargers that feed up to 16-17V are safe for use with cars.

Some pulse chargers do that, but as for the Batteryminder, I've had absolutely no issues with it in the 5 years I've had it. I've got more than one of them and have them attached to cars that I don't drive regularly and have had absolutely no issues with the car in that regard.