Why does a matchbook sized cell phone battery require 3 hours to charge

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Reply to
craigm
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The articles are great, very helpful and informative. Thank you very much.

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Reply to
Ignoramus5268

All the stories I ever heard had to do with lithium ion, which is fussier (extreme intolerance of overcharging) and involves more reactive chemicals. In that past year, I have been hearing a lot fewer horror stories.

NiCd and NiMH is easily overcharged by slow charging. NiCd usually tolerates slow-charge overcharge well, with a slight voltage depression that can generally be fixed by full discharge followed by full charge without overcharging. NiMH appears to me less tolerant of overcharging, and prefers fast chargers because faster charging enables better detection of full charge. Smart chargers for NiCd and NiMH tend to have charge times 4 hours or less.

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

My guess is it's lithium ion. Typically those can be recharged most of the way at a rate that can charge them in an hour or so, but "topping off" requires strict adherence to a cell voltage limit (or else a cell safety feature breaks the internal cell connection, otherwise KABLOOEY). At that strict voltage limit, it appears to me to easily take a couple hours to get the cell to accept the last 20-30% or whatever of a fulll charge.

Lead-acid is similar, except much less serious damage if the cell voltage limit is exceeded from fully charging with a fast charge. (as long as the resulting hydrogen and oxygen do not get ignited) Much less still if the cell has provisions to replace the electrolyzed water.

It's probably NiCd or NiMH. With usual modern "smart charging" technology, plenty probably most of those can be reasonably safely recharged in maybe an hour, even less if designed for faster charging.

I suspect with not quite a full charge. Keep in mind that the "fuel gauge" battery charge indicator appears to me to be full when the battery is above maybe 60-70% or so.

It appears to be mainly a Li ion often taking a lot more than an hour to get really fully charged in a safe manner.

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

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