IMR batteries for daily use?

I know you're not supposed to let IMR batteries stay in discharged state for too long, but how discharged is too discharged and how long? Like if I use my light for a few minutes at a time over the course of a month, am I better off with a lithium Cobalt?

Most of my cells are high drain, i still have a few pany B cells (unprotected) in use here and there, but most are high drain. Most specs are 2.5 - 2.7v up to 4.2v . Ideally you dont want to go bellow 3v which today most lights wont allow you to and shut down, blink or give an indication telling you to charge the cell due to low V. Which light are you using it in? Even though your using it for a few mins a month, depending on what output you may still need to charge regular.

After a weeks use, measure the voltage and get an idea of what you have used, for example it may show 4v, then after 2 weeks 3.8v, 3 weeks 3.6v (just examples). So then you may decide to top off the cell every 3 weeks if your use is consistent. Or simply once a week, and get into a routine. My work lights get charged daily(one i have been using), either at the end of the day or next morning. Voltages tend to be around 3.6-3.8v, but even if its not been used too much that day(4v) i still top it off, as any day could end up being hours of use. I always have spare cells anyway, so they get rotated when they get topped back up.

No chemistry likes to be discharged and left(flat) or as far as i am aware anyway, some are more tolerant to this , but it is still not good practice . So depending on use, top off frequent(days) or week/s on use. Its worth while finding out how much use your asking of your cells to get an idea.

It'll be in an olight s1 or Fenix e15 that I run on high fairly for a few minutes, a few times every month.

GarageBoy said:

It'll be in an olight s1 or Fenix e15 that I run on high fairly for a few minutes, a few times every month.

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Right, these little 16340 cells dont hold much energy, usually around 600mah give/take. So i would measure(maybe a multi meter or your charger has V read out) the cell after a week to check voltage. Even so, with these little cells, i would get into the practice of charging weekly or even sooner, rather than monthly..................does not take much to get them down to 3.6v which is around 40% charge(+ or -). A couple of days use, a little longer than planned could literally leave you in the dark if left too long before topping up. It would be interesting from 4.2v, after a week what the typical V is.

My 16340 cells do get regular topped up, certainly compared to my 18650 cells. Seems like little use gets them low on V , this will also effect your higher modes as the V sag will drop out of turbo or even highs once the V gets in the lower 3's.

Thanks - I guess I'll just top them off as I go along

GarageBoy said:

Thanks - I guess I'll just top them off as I go along

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If you can, check the V then you can roughly work out how regular(or maybe not) to top the cells off. But as these cells dont hold too much energy, its better to top off regular if not sure. You never know, you may need the light for a lengthy duration and having the cell already depleted could leave you in the dark. Its worth having a back up cell and just swap out the cell when recharging, and rotate etc.

If your lights has low voltage protection, it'd be hard to mess up badly, really.

The problems with LiIons are mostly if you either discharge them far too low, or throw them on a shelf after discharge, and let self-discharge finish the job.

If undervoltage protection is in place (step down is just another such protection), you use it often enough that you'd notice, and charge when it's spent, it'll be just fine.

If there's no protection in your light at all, then I'd consider a protected cell, that includes undervoltage protection.