Author Topic: Battery charger advice  (Read 2049 times)

Offline Deefadog

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Battery charger advice
« on: 23 August 2004, 21:20 »
A few questions  would like cleared up over charging your battery.

1) Is it safe/recommended to charge the batery directly to your car without removing the live and earth?

2) can you remove the battery completely and attach the 12V charger to the live and earth and test the car like this? would it do any harm?

Just an argument i was having with a mate! :)
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Re: Battery charger advice
« Reply #1 on: 23 August 2004, 22:24 »
im sure you dont even need to remove anything fromt the car.

I just plug and charge and im sure its safe. Not sure on cars with airbags though?

Offline tobz.

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Re: Battery charger advice
« Reply #2 on: 24 August 2004, 10:15 »
Shouldn't be any problems in just connecting a battery charger up to a mk2 with the battery still in place.

As for removing the battery and just connecting the battery charger.......yes it will run some things e.g. clock interior light etc. But if you try to switch the ignition or anything like that on it will just blow the fuse in the battery charger (fuses are normally about 5amps unless you have a really hefty battery charger).
I used a battery charger in this manner once to locate a fault which was draining the battery over a few hours.

Toby


You got any pics of your dad's split ?

Offline Deefadog

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Re: Battery charger advice
« Reply #3 on: 24 August 2004, 12:47 »
Just as i thought :)

Just wondering, what pushes the amps in a car? I know in the house that the Amps (force) of 240V is 100 and is supplied via the sub stations, but in a car you just have 12V form the battery, so what creates the force of flow (Amps)?

Thanks
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Offline jazzygm

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Re: Battery charger advice
« Reply #4 on: 24 August 2004, 12:55 »
the battery lol.
The battery will output 12V till its near dead, its the amount of amps that decrease as it loses its charge AFAIK.  ;)
When you make a circuit by turning the key or by opening the door, electrons are free to go running around the circuit, and the battery happily flows, when there is no circuit, electrons go nowhere and the battery cant do too much!
Someone feel free to add something - my grasp of electricity is a little weak (and i do physics haha  8) lol)

Offline Deefadog

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Re: Battery charger advice
« Reply #5 on: 24 August 2004, 15:09 »
Volts and Amps are different, Amps is the pressure that push the 12V around so 12V x 5Amps gives you 60 Watts etc

So what is the total Amps pushed out at the start? as the fuses creduce the amps down for the correct cicuit!
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Offline tobz.

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Re: Battery charger advice
« Reply #6 on: 24 August 2004, 16:38 »
Amps are the measurement of current that something is drawing. It doesn't work that your battery is trying to shove out loads of amps and that the fuses are restricting the flow, the current that flows in a circuit is a result of the resistance of the circuit and the voltage applied to it. If you have a 5A fuse in a circuit it doesn't mean that 5amps will flow in that circuit just that you wont be able to draw more than 5amps as the fuse will blow.
Try to think of amps as the result of a circuit pulling current from its supply rather than the supply shoving current into the circuit.
As for your question about how much current is available at the start, when you operate your starter motor you could draw in excess of 100A for a split second until the engine starts turning. Lead acid batteries as found on cars are capable of supply hundreds of amps for a split second.
You normally find a rating on a car battery for which the unit is Ah which stands for ampere hours. A typical battery would be 50Ah which means it could supply 1amp for 50 hours or 50amps for 1hours.

Hope this helps (sorry if it's a little confusing I'm terrible at explaining technical stuff)

Toby


You got any pics of your dad's split ?

Offline Deefadog

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Re: Battery charger advice
« Reply #7 on: 24 August 2004, 18:25 »
Thanks mate, I got it wrong somewhere :)

Great help
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