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Rechargeable batteries question

May 7, 2008

MainFragger's picture

My dad and I are having an argument. And most of the sites I've gone to to try to settle the argument kind of leave a small grey area that neither of us is willing to conceed proves the other's point.

Our disagreement is about how rechargeable batteries work.

Our argument started when the ad we read about 15 minute chargers stated they are green because they use less electricity because they don't charge as long.

My dad said, that just means that they have to put the same amount of electric in faster, which means you are still using the same amount, and its not really green.

Ideally, I feel that the charge is part of the chemical, and that the electrons are passed from the cathode to the anode through the chemical, and then when a reverse charge is applied to both -odes the electrons are passed back to the original starting position. In an idea world, the battery is fresh again. But in usage, nothing is lost, ideally (I realize this is not totally true, but it just makes it easier to explain), if there were 1,000 electrons moved from the negative to the positive pole, then 1,000 electrons are then reversed by the presence of the revered electric fields at the poles.

My dad feels the charger puts electric directly into the battery. I feel it just provides a reverse current to put the already present electrons back at the negative pole. My dad argues that energy has to be used in the electric process, and that its not possible that all of the energy is still in the battery. I argue that the electrons generates a field that generates electric as it passes through the circuits of the device, but that the electrons themselves actually go through intact and unused and end up at the positive pole of the battery.

Depending on which of us is right.. What is the validity of the claim that the 15 minute batteries use less electricity to recharge and are therefore more green than other batteries?

Anyone care to settle our argument?

Comments

You are right, but...

May 8, 2008 by Anonymous, 1 year 8 weeks ago
Comment id: 29710

Both the batteries and the charger can get quite warm during the charging and that is where the 15 minute batteries save a lot of power. The heat is a result of low efficiency of the transformer inside the charger and resistance of the batteries. The efficiency of normal chargers is probably somewhere between 60 and 70 pecent(maybe even less), that means 20-40% of the energy is transformed to heat.

The trick of "green" chargers is that they are more efficient. These ultra-fast chargers only charge the batteries to 85% of their capacity because the efficiency drops rapidly beyond this point. If you leave the batteries in, most of these chargers will continue charging the batteries slowly until they are fully charged.

Some time ago, Varta released another type of green batteries that do not self-discharge over time, but that is not related to the topic.

Both could be right

May 8, 2008 by Anonymous, 1 year 8 weeks ago
Comment id: 29699

I think that you are correct, in that it is a chemical process where the recharger simple applies an electrical current to run the chemical process in reverse.

However, it really comes down to what the recharger is pulling over those 15 minutes. It actually may be drawing more current in fewer amount of time. So it may be greener, but not by much. So your dad could be correct also.

It would be interesting to test how much power it uses in 15 minutes vs a regular charger.



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