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  • Recharging Li-Ion & Li-Po batteries.
  • I think Ay Up quote 500 recharges as the life of their Li-Po batteries.
    Is that 500 full charge and discharge cycles ?
    Would that then be 1000 half discharge and recharge cycles, or is it not that simple ?
    My commute takes about 40 minutes, so I need to recharge my 3 hour battery every four days, assuming only one direction is done in the dark.
    I like to be prepared for the possibility of a long detour on the way home, so I tend to recharge it after 2 or 3 days to keep a bit in reserve.
    Am I reducing the overall life expectancy of the battery ?

    Same goes for my Li-Ion drill battery.
    I usually fully recharge it after every use, even if it was only for a couple of minutes, so it will be fully charged next time I need it
    Should I wait ’til it’s flat before I recharge it ?

    molgrips
    Free Member

    Well with Nimhs you can radically improve their life (almost indefinite) by only charging from say 40% to 80%, but you of course lose lots of capacity.

    I THINK that the reason Li-ions lose capacity is that the battery material actually needs to expand slightly to accomodate the charge (yes I know it sounds silly, something to do with crystal structures or whatnot, not sure). And over time, the material loses its flexibility and can’t expand as much.

    This was the basis of that news article a few years ago that said scientists thought they could make li-ion batteries that lasted 10 times longer – the material was more flexible and better organised on a microscopic level.

    So if the above is true, (which would tie in with the fact about NiMHs) then yes, you would be extending your battery capacity by not fully discharging it all the time. Also by not fully charging it each time too.

    zokes
    Free Member

    Li-Po batteries

    Are these:

    a) The result of plastic surgery
    b) A new line in ever-lasting batteries pedalled by the FSB?

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    Del
    Full Member

    lithium packs should be stored part charged ( or part-discharged ) and in the cool. they should be refreshed in the charger if in storage for long periods to prevent them falling too low.
    nimh should be stored charged at room temp.

    molgrips
    Free Member

    “High charge levels and elevated temperatures hasten permanent capacity loss”

    Interesting, this could explain why laptop batteries fare so poorly. They get pretty warm all the time.

    Thanks for the link, mmb.
    Looking at Table 2 on that page, they quote 500 discharge cycles at 100% discharge and 2500 cycles at 25%, so it looks like I should be recharging my batteries after every ride.
    Going by Table 3 though, I should ideally be leaving my batteries discharged to 40%, then recharging them immediately before use.

    Back in the real world, I’ll stick to what I’m doing now.
    I may be slightly reducing the battery’s capacity, but I’m also slightly increasing the battery’s life.

Viewing 7 posts - 1 through 7 (of 7 total)

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