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Energizer Rechargeable Battery — Parallax Forums

Energizer Rechargeable Battery

edited 2010-10-06 02:15 in General Discussion
I have two different chargers for Energizer batteries and once in a while the batteries feel hot while charging. I suppose they felt like they were around 100F which I felt by hand and I suspected that there was a smell. I never charge the batteries when I'm not home and they haven't been a problem but I'm getting concerned.

I need the rechargeable batteries because they last at least a day or more in my Canon Powershot camera and regular batteries do not.

The older batteries were the 2500 mAh and the ones I recently bought are 2300 mAh.

I'm not looking for alarmists even though I'm careful and keeping an eye out but I'm curious what others have to honestly say.

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-10-03 20:27
    Not to sound alarmist, either, but: http://forums.parallax.com/showthread.php?t=120396

    A lot depends on the sophistication and reliability of the charger. I've not been disappointed yet with the Ansmann charger cited in that thread, which replaced the charred RS unit.

    -Phil
  • edited 2010-10-04 06:15
    Thanks, Phil.

    I understand that anything can malfunction and anything can catch on fire. I take it for granted that accidents can and do happen.

    My question is, is it normal for a battery to get this hot and what is happening on the inside of the battery when they get this hot?
  • schillschill Posts: 741
    edited 2010-10-04 06:46
    I have used some quick chargers where the batteries get pretty warm - but not too hot to touch. I believe this is normal (although I'm not always comfortable with it).

    The referenced thread has a lot of good information.

    I used to use only batteries from Powerex or (Japan manufactured) Energizer. I've switched over to mostly using Sanyo Eneloops these days. They were the first with extended shelf lives and I've been happy with them.

    I have a couple different chargers I use and if I have the option I will usually use a slow charge rate. It keeps the batteries cool. I also prefer chargers that charge each battery individually. I've been very happy with my 8-cell Maha charger (I've been happy with every Maha charger I've used).

    There are some very nice chargers with sophisticated functions for cycling your batteries and advanced charging algorithms. But, you still hear about them occasionally melting down so it's always good to monitor things yourself. I will leave batteries charging overnight, but I try not to leave anything charging while I'm not home (if I need to charge, I take the charger to work).

    I do have a small ceramic bunker for charging LiPos, but it's not large enough to hold my NiMH chargers.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-10-04 09:07
    I have a couple Ray-O-Vac NiMH AAs that get warm in the Ansmann charger and which the charger seems not to recognize as fully charged. So I don't leave those charging unattended. The other batteries -- including the Ansmann batteries that came with the unit and a field run of others -- stay cool while charging, and the charging cycle terminates normally.

    -Phil
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2010-10-04 11:19
    Here are the rule that I follow when charging nicad/ NiMH batteries

    ONE >> when I put a battery to charge one at a time first and see how FAST the charging voltage goes up

    SECOND >> I do a discharge test to see if they can hold a load and see for how long

    THRID >> I only put the same type of result type batteries and brand and milliamp hour rating
    together to charge at the same time

    Radio Shack Computer Control

    When you first start the charger it start a pulse to see if the voltage goes up if it dose then the next step is >>

    Soft Start mode is not really soft start because it start with 1100 milliamp charge rate

    Fast mode is where the charging current start to come down to 600 milliamp or less

    Slow mode pulse a 200 milliamp charge rate

    I watch this charger until it get into the fast mode

    Most battery that I try to charge with this charger have been in my solar light in the yard and maybe to far gone already and do not want to charge and when this happen I very slow charge these battery 1 tenth of the battery amp hour rating or 20 milliamp is the min charge rate for 24 hours then use the Radio Shack Computer Control one to test these battery again

    If they still do not want to charge right then I get rid of them

    ONE NOTE if any battery is more than a little bit warm I do not charge it in that charger
    I check ALL battery with this charger first

    When I check power tool batteries I do this test a little different in that if the battery dose not make it to the fast charge it may be to far gone to be used again for a power tool battery tool pack

    I very slow charge these battery 1 tenth of the battery amp hour rating and then test each battery one at a time if in the load test dose not last longer than 15 min at 1.25 volts @ 1000 milliamps because as the voltage goes down the amperage also goes down

    The battery fail the test and is not use for this any more
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2010-10-04 11:52
    One more note on battery that I have found that are China made battery
    Power tool one hour battery charger DO NOT charge the battery all the way up because the charging voltage goes to high this also hold true with the Radio Shack Computer Control Charger one note if the battery voltage stays the same for a long time it seem to have a long time out before turning the charger to the slow mode this a ? mark for me might be a problem do not know I have seen a few batteries become a little bit more than warm not hot but some thing I have seen in the past now after reading what happen to your I am watching this more closely than ever Thank for posting it


    Japan manufactured Battery work the best in these type of chargers


    Now the China made battery will work very well in charger where the current is constant and the voltage dose not matter
  • Spiral_72Spiral_72 Posts: 791
    edited 2010-10-04 13:21
    If this is an overnight charger, the batteries should barely be above room temperature. If it's a quick (1-2hrs) then I would consider 100F normal. IMO


    I have the same setup, but Duracells, 2650mAh with an overnight charger. The batteries are barely warm to the touch, MAYBE 90F. When I charge hobby batteries at home with the Triton at 1C they can easily get 120F.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2010-10-06 02:15
    I have long suspected that the primary reason most modern chargers outside of Lithium ion do not provide a thermal detection sensor is that the manufacturers just sell more batteries (and more chargers) when you forget and leave the batteries in the charger.

    Something similar happens with the modern clothes dryer. If you use the heat, your clothing lasts maybe 1/5th as long as drying cool. I should know. Since I relocated to Taiwan where my jeans are sun dried, they last 5 times longer.

    If you get a 10k thermistor, a BasicStamp, and a solid-state relay; you can have an automatic thermal shut down that is likely to save you some $$$$ and be much safer than your existing set up.

    Without thermal shut down, the only safe place to leave batteries charging is on a concrete floor and away from anything that might suffer damage from a burst battery.
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