Chargers?

[Electroenthusiast]

Why Do Mobile Chargers and other electronic chargers have strange pins, unlike plugs?

 

[smanches]

Show an example of "strange pins."

 

[MikeMl]

Why Do Mobile Chargers and other electronic chargers have strange pins, unlike plugs?

So that APPLE can charge $30 for a charger that should cost $3.99! Its purely MARKETING.

 

[Electroenthusiast]

So that APPLE can charge $30 for a charger that should cost $3.99! Its purely MARKETING.

Thnks AND I HAVE ANOTHER QUES ON CHARGERS...

If the gadget is rated charger is 500mA and the output of another charger is 350mA (BOTH 5.7v);

can i use it to charge the Gadget?

?2 :What if the output voltage of another charger is less than 5.7? like 5V 500mA ?

 

[cowana]

The current is the MAXIMUM current it can give, so you can use a 5.7v 500mA charger instead of a 5.7 350mA charger.

If the voltage is less, then it can't be used (probably, depending on the application).

A

 

[Electroenthusiast]

The current is the MAXIMUM current it can give, so you can use a 5.7v 500mA charger instead of a 5.7 350mA charger.

If the voltage is less, then it can't be used (probably, depending on the application).

A

i know its the maximum output current of the charger; what if its low and the gadget require 500mA?
in the same way, what if voltage is less?(ex: 5v instead of 5.7c)

 

[cowana]

Too low current, and the charger will probably overheat.

Too low voltage, and the gadget probably won't work, although a low voltage is not going to damage it.

 

[Electroenthusiast]

Too low current, and the charger will probably overheat.

Too low voltage, and the gadget probably won't work, although a low voltage is not going to damage it.

how does low current overheat the gadget? ....& i'll just use it to charge.... can i do that?

 

[MikeMl]

It is possible (but not too likely) that the charger might overheat; not the appliance.

If the current rating of the new charger is 350/500 of the original charger, then it will take 500/350 ~= 1.5 times longer to charge the appliance.

 

[Electroenthusiast]

If the current rating of the new charger is 350/500 of the original charger, then it will take 500/350 ~= 1.5 times longer to charge the appliance.

What if the Voltage is 5V/ 5.7 IS OF ORIGINAL CHARGER?
I guess i shouldnt use a charger with rating more than 500mA and 5.7V

though 6V might be used? what do u say?

Edit: Battery i want to charge is here: Voltages also specified there https://www.electro-tech-online.com/threads/battery-why-and-how.107510/

 

[MikeMl]

What if the Voltage is 5V/ 5.7 IS OF ORIGINAL CHARGER?

Then the battery may not charge at all. The voltage requirements for properly charging a battery are determined by the electrochemistry of the battery. If the voltage doesn't reach the potentials required by the chemical reactions, no charging takes place.

 

[Electroenthusiast]

Then the battery may not charge at all. The voltage requirements for properly charging a battery are determined by the electrochemistry of the battery. If the voltage doesn't reach the potentials required by the chemical reactions, no charging takes place.

Thanks!
Yep; i came to conclusion that it wont get charged after thinking for some time!!

 

[Electroenthusiast]

Another Ques: Is the Voltage of Slightly Discharged Battery same as that of Charged Battery?
I ask this because i found no difference b/w them; then how does charging take place without the difference in Voltage (Back EMF).

 

[dknguyen]

Another Ques: Is the Voltage of Slightly Discharged Battery same as that of Charged Battery?
I ask this because i found no difference b/w them; then how does charging take place without the difference in Voltage (Back EMF).

Yes it is different. How much it is different by depends on the battery chemistry. Sometimes the battery chemistry is very sensitive to overvoltage/overcharging and the voltage difference is too small to reliably charge the battery. Many new lithium batteries are very sensitive to overcharging and if you overcharge them so their voltage is beyond the maximum allowable level they get damaged, catch fire, or explode.

In general, you don't measure voltage difference to figure out when the battery is full (well you could with some batteries), but that's not good enough for lithium batteries that get damaged, light on fire, or explode when overcharged. The best way is to measure the charge current.

At the first the charger acts like a current source- it slowly increases the voltage to maintain a constant charge current going into the battery which is at a level that is safe. When the charging voltage finally reaches the maximum battery voltage allowable by the battery chemistry, the charger becomes a voltage source. It stops increasing the voltage the battery can't exceed it's maximum voltage where bad things happen. It just continues to apply the maximum battery voltage. So how does it know when the battery is full? Well, it monitors the charge current. The charge current will decrease as the battery continues to become more full. Once the current falls below a certain threshold, the battery is considered full.

Basically the charger knows the battery is full if it is applying the maximum voltage allowable to the battery and the charging current being drawn is low enough.

 

[MikeMl]

dknguyen has almost perfectly described charging lead-acid batteries, which have a predictable rise of voltage at end-of-charge. A lot of other battery chemistry types do not have a reliable ΔV at end-of-charge. Rather, under a constant current charge, after the power input stops going into the chemical reactions (which end when the battery is fully charged), the power begins heating the battery, instead. The charger measures the temperature rise of the battery to decide when to quit charging...