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Can chargeable things be left plugged in

Posted by tobr24u (My Page) on
Mon, Sep 3, 12 at 6:59

all of the time? And should the transformers be left in outlets when device is not charging. I have dustbusters and other items and wondered if they would be hurt by constant charging, of if their transformers are harmed be being plugged in when not being used to charge...


Follow-Up Postings:

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RE: Can chargeable things be left plugged in

When plugged in those transformers use electricity. Generally it's not a lot of electricity but enough of them over time does at up.


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RE: Can chargeable things be left plugged in

But the question isn't the electricity used, but rather the constant charging harming the machine/battery.


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RE: Can chargeable things be left plugged in

I've heard divided opinions. Some say for maximum life it's best to charge a battery, disconnect it, and run it down and repeat the cycle. Others say keep it plugged in, it doesn't mater. Take your pick. Fortunately, most of the things with rechargeable batteries are either relatively inexpensive items, or are of a type that replacement batteries can be bought.

mike is right, all the plugged in items in a house draw power and it does add up. This is called the "phantom load". If you're going away for more than a few days, it's a good practice to unplug all those things (including TVs) that draw power in a standby mode.

PS - I think power supplies/wall warts that power electronic devices are theoretically rectifiers, not transformers. No matter, the "transformer" term is widely understood and used.


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RE: Can chargeable things be left plugged in

They are both rectifiers and transformers. The transformer converts 120VAC down to a lower AC voltage, and the rectifier converts it to DC for battery charging.

Older NiCd batteries DO develop memory, and lifetime is extended by not leaving them on the charger all the time, but charge, unplug, use, recharge. Newer NiMH batteries do not have much of a memory problem, so it doesn't matter so much.

One thing to keep in mind is the both batteries and chargers can fail and cause fires. Rare, but it happens. It's better to leave things unplugged.


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RE: Can chargeable things be left plugged in

"When plugged in those transformers use electricity. Generally it's not a lot of electricity but enough of them over time does at up."

Not enough to matter.

An unloaded transformer has a VERY small power dissipation.

Even the with a rectifier circuit on the output of the transformer, the capacitors charge up and the leakage is VERY tiny.

This whole thing is caused by some fool that measured the current without looking at the phase angle to the voltage.

Just like the 'power factor corrector' charlatans.


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