Tuesday, January 21, 2014

Bateri Handphone

Saya selalu mendengar pelbagai pantang larang mengenai bateri handphone. Antaranya ialah sebelum menggunakan kali pertama, sila charge 8 jam dahulu. Ada juga nasihat charge bateri yang terbaik adalah apabila bateri dah nak habis. Apabila saya membeli handphone baru, manual handphone tersebut akan saya belek untuk melihat samada pengeluar ada memberi amaran untuk charge bateri dahulu selama 8 jam dan charge handphone apabila kuasa bateri sudah dibawah certain amount.

Tapi malangnya, nasihat-nasihat dan pantang-pantang tersebut tiada dalam manual handphone. Jadi saya pun cuba mencari sendiri di internet. Pelbagai pendapat saya perolehi di pelbagai laman web dan forum tetapi saya tertarik dengan satu pendapat forumer di Android Forum di laman web http://androidforums.com/incredible-tips-tricks/69534-battery-charging-myths.html. Pendapat ini disuarakan oleh seorang user menggunakan nickname computerpro3.

I've seen a TON of people saying stuff like "It will hurt the battery if you use your phone before charging it" and "You need to do a full charge/drain cycle" to protect your battery.
That's just not true. It won't have any effect at all, not even a minor one. Trust me; I've been a "battery hobbyist" for nearly a decade now. Lithium-Polymer and Lithium Ion batteries have no memory effect whatsoever; these warnings and advice that you're reading are a carryover from previous battery chemistries where it was good to be do several full drain/recharge cycles.

With Lithium Ion, in fact, is actually very bad to do a full discharge and it will reduce the capacity of your battery. 4.2v is full charge for lithium ion/Lithium Polymer, and there is a protection circuit built into the battery somewhere around 2.4-2.7v. Once that threshold of discharge is reached, the battery will cut itself off to prevent even worse damage. This is why sometimes a phone will have trouble turning back on after the battery totally dies - the battery has to be recharged past the cutoff threshold before the phone will start up again. This is the point where you have "0%" battery life left on the phone. It's much better to charge your phone frequently than to do full charges and discharges - it will keep your battery in much better shape. Now, a full discharge once in a while won't totally kill your battery, but it will reduce the recharge cycle life of the battery. Not a ton, but it will nonetheless.

Other than avoiding full drains, the other thing you should do is to only use high quality chargers. Now it won't matter much if you charge the battery in your phone as the charging algorithms are software controlled in the phone itself, but I would be very wary of using generic ebay wall chargers like the following for the loose or extra batteries. 

Lithium Ion gets damaged if charged past 4.2-4.25 volts, and becomes an explosion risk should the internal vents fail. The problem with many cheap chargers is that they continue to slowly trickle charge past 4.2v, so you'll be fine if you use a DMM to check the voltage of the batttery every ten or so minutes, but if you don't it will slowly rise to 4.21, 4.22, 4.23v. If you leave it overnight you very well may end up coming back to an overcharged battery that is not only holding reduced capacity from the damage, but is a safety risk as well. I even go so far as to have special hobby chargers with perfect algorithms to charge my loose lithium ion cells for my flashlights!    

Kalau mengikut kata user ini, tiada masalah untuk charge bateri walaupun bateri masih ada 80%. Malah tidak bagus untuk melakukan full discharge. Dia juga menyarankan menggunakan bateri charger yang bagus kerana ia mempunyai cut off apabila bateri kita sudah full.


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