Do I really need to fully charge my new Ipod battery?
Lithium-ion is a very clean system and does not need priming as nickel-based batteries do. The 1st charge is no different to the 5th or the 50th charge. Stickers instructing to charge the battery for 8 hours or more for the first time may be a leftover from the nickel battery days. Unlike nickel and lead-based batteries, a new lithium-ion pack does not need cycling through charging and discharging. Priming will make little difference because the maximum capacity of lithium-ion is available right from the beginning. Neither does a full discharge improve the capacity of a faded pack.
You are looking in the wrong direction here, Science. The first-time charge-up is likely for the protection circuit, not the battery itself. Case in point: Last time I bought a third-party battery for a laptop, I let it discharge all the way to see what would happen. The laptop’s battery meter hit 00:00 left . . . and thirty minutes later, the battery gave out. A full charge cycle after that, and the laptop never gave an inaccurate reading. The lithium-ion cell packs don’t care about memory issues, but remember that li-ion packs are stored around 40% charge. They’ve never been full-cycled in a product before hitting the retail shelf.
The main reason to do a full charge is to calibrate the battery gas gauge. Partial charges are just fine for lithium ion batteries. They don’t have any “memory” problems like NiCads. But after a few dozen partial charges, you need to do a full charge again to recalibrate the gauge. If the gas gauge is not properly calibrated, it may cut off operation prematurely.
Not an EE, not a chemical engineer, but 10 years day to day working technical experience with rechargeable cells of all types has given me a good knowledge of them – and a healthy respect for the Li-ion & Li-pol types. With any of the Li-based cells, the initial charge instructions are more to do with starting off in a known state than anything else. Li-ion & Li-pol cells don’t really show many of the self-limiting charge or discharge characteristics that Pb, Nicad, or NiMh cells do, while at the same time having much more extreme consequences to overcharging and over-flattening. Since they don’t show obvious charge / discharge endpoint indications, the charge monitors work mainly on time, current in/out, and temperature. Except in certain specialised applications, rechargeable Li-based batteries are required by law in most countries to have a built-in charge monitor/controller to prevent these consequences.
