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Thread: Small li-po batteries

  1. #1
    Senior Member+ MichaelMeissner's Avatar
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    Small li-po batteries

    At the instance of my wife, I have been trying to organize my 'man cave' (otherwise known as the living room), and clear off all of the spaces that have various camera or electronic parts. To that end, I've been sorting things into various containers and drawers. One such area is rechargeable electronic project batteries. Over the years, I have collected several different lipo batteries with the 2 wire JST cable. I mostly use the batteries that are at least 1000ma in capacity. Since these batteries are roughly Teensy size, I can just mount the battery under the Teensy.

    However in buying various dodads over the years, I have a collection of smaller lipo batteries, ranging in capacity from 110ma to 500ma. Before putting the batteries away, I attempted to charge them, and I discovered that the small batteries no longer work, while all of the larger batteries can hold a charge.

    Given all of my small batteries appear dead, but the larger ones aren't, is there something about the smaller lipo batteries that causes them to fail sooner? Or is it just luck of the draw?

    Now, I don't track when I buy the batteries, but I know 1-2 of the larger batteries that still can hold a charge were bought several years ago, while at least a few of the lipo batteries were bought more recently. I could understand older batteries losing the capacity to be charged, but that doesn't appear to be the case here.

    I suspect because I do use the larger batteries every so often, that using and recharging them keeps them active. While with some of the smaller lipo batteries, I might never have used them.

    I've bagged these batteries so that i can properly dispose of them at the town transfer station that takes trash, recyclables, food waste, and it has a shed for lithium batteries and lights with mercury.

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    Older 'soft' package LIPo batteries have less immunity to mechanical damage and can be prone to separated electrodes when compared to liquid electrolyte Li ion batteries. You probably already know this, but the three major stressors for Li batteries are complete charge cycle count, thermal exposure, and charge control for the transition from CC to CV.

    Self-discharge, when compared to nickel batteries, is essentially non-existent. But improper charge control and the end-use UV lock-out can be a big negative for Li battery life.

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    Senior Member+ MichaelMeissner's Avatar
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    Quote Originally Posted by BJB View Post
    Older 'soft' package LIPo batteries have less immunity to mechanical damage and can be prone to separated electrodes when compared to liquid electrolyte Li ion batteries. You probably already know this, but the three major stressors for Li batteries are complete charge cycle count, thermal exposure, and charge control for the transition from CC to CV.

    Self-discharge, when compared to nickel batteries, is essentially non-existent. But improper charge control and the end-use UV lock-out can be a big negative for Li battery life.
    In this case, I rarely use these batteries. When they came with a project, I just tossed them in the drawer. It was just as I was rearranging things, I decided to charge them up, and found they wouldn't charge. I could imagine a few of them the wires have been broken (BTDT), but I was surprised that all 6 of the small batteries that I had no longer held a charge. No big deal either way, since the batteries are too limited in capacity that I would consider using them.

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    Senior Member+ defragster's Avatar
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    I've gathered a few older ones - when I see them I'll put them on a proper charger - they are charge rate sensitive - smaller ones need fewer Ma pushed at them in proportion to their size. I've not cycled or used them much as that was pre-Teensy 5 yrs now?

    If left sitting uncharged to to the point of discharge the chemical factory goes offline.

    I have gotten some newer ones - not used much yet - but more inline with lower power than Teensy devices that I expect to work well if not left to die, or charged too fast.

    Quality makers have improved charge retention cycle use and loss over time - cell phones needed fresh cells before they were paid off when replaceable - or when not replaceable lasted longer but then it was time for a new phone. But the cheap unbranded ones likely lack such quality control or construction.

    Saw a spec a year or so back that Samsung got there losses under 10% per year of use.

    This link seems a good summary: 3dinsider.com/lipo-lifespan/

    where bad is storing fully charged (so my topping them off might lead to early demise) and worse is when it is stored discharged:
    On the flip side, storing a battery that is completely drained runs the risk of the battery’s protective circuit failing. This means that a battery that goes into a “deep discharge” state might not be able to hold a charge at all.
    This might explain not taking a charge

    This shows the change in battery life up to 4 years ago: phonearena.com/news/Smartphone-battery-life-over-the-years-A-surprising-study_id82315

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