Saturday, June 30, 2012

The battery myth

Yesterday when I went to buy camera with Sam and as usual the sales person advised the user to charge the battery for at least 8 hours before first use. Almost all the seller will advise you the same thing.

So, what is real reason behind this first time full charging advise?

Back to long long time ago, when mobile phone was introduced, the rechargeable battery technology started from Nickel Cadmium. One of the major flaw of NiCd battery is that it has "memory". If you charge the battery until 80% and stop, then the battery will assume the 80% is the maximum charge that the battery can hold. Same happen to discharge, if you discharge until 20% and then start recharge it back, then the battery will remember that the 20% is the zero charge of the battery. Therefore the total charge that a battery can hold and supply is getting narrow and narrow if the battery didn't charge until full or didn't discharge until empty. That's why the seller will advice the user to charge their battery until maximum before first use, normally 8 hours or more.

However, gadgets nowadays are usually equipped with Li-ion battery instead of NiCd and Li-ion doesn't suffer the memory effect which NiCd was suffering. You can actually use the battery immediately without charging it and you do not need to charge it for 8 hours for the first time. Most of the gadgets are now equipped with auto-cutoff charging circuit when the battery is fully charge, therefore, you just need to plug it into the power socket when the battery is flat and the charger will do the job for you. But, if the charger does not has cutoff circuit, then you need to use a timer to disconnect the charger to avoid overcharge which will eventually spoiled the battery or worst, explode.

One of the drawback of Li-ion is that it can't be over discharged. If the battery has been over discharged, for example the battery has not been used for few months, then the battery will no longer able holding any charge.

So, next time you can tell the seller that this 8 hours initial charging is no longer valid for Li-ion battery.