09-08-2011, 03:09 PM
Yes. I should have said that when my new phone arrived recently the battery was in a separate plasic bag.
Alan
Alan
NiMh CHARGING
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09-08-2011, 03:09 PM
Yes. I should have said that when my new phone arrived recently the battery was in a separate plasic bag.
Alan
09-08-2011, 03:39 PM
(09-08-2011, 12:21 PM)Bluebottle Wrote: The batteries I've just received arrived with a terminal voltage of below 1.2v so I put them on charge for a top-up. O.K. - so these are ones that you've just received. Are these the same ones that you referred to earlier? If not, can you tell us what the measured voltage was for the original shipment of batteries - the ones that you said needed charging and when on charge, get very hot? Thanks. I'm getting a bit confused now, as you can tell! Al.
09-08-2011, 06:03 PM
(09-08-2011, 03:39 PM)Skywave Wrote:(09-08-2011, 12:21 PM)Bluebottle Wrote: The batteries I've just received arrived with a terminal voltage of below 1.2v so I put them on charge for a top-up. Same ones, Simples !!
Thank you - now I understand: all is becoming clearer.
Reviewing what has been written so far then, it seems that you originally connected these batteries to a USB port via a 'mini-charger'. There have been several comments about the current-capacity of a USB port for this purpose, generally implying, or stating - that the current available from that port will be insufficient to cause damage - or overheating - of those batteries. However, that then gives rise to the following question: what is in that 'mini-charger' and what is its output voltage on no-load and what is its output current capacity? These figures may not be directly related to the corresponding figures for the USB port that powers it: the mini-charger may incorporate some form of voltage step-up for all I know (thinks: SMPS inside the mini-charger?). This, in turn, may produce a charging voltage that is in excess of that required, and if that rated output current is available at that excessive on-load voltage . . . the batteries will be over-charged . . . and get hot . . . possibly really hot! Just a few thoughts that may help. Al.
10-08-2011, 10:13 AM
Here's a link to a useful .pdf document from National Semiconductor detailing the differences in charging requirements for NiCd, NiMH and Li-Ion cell types and giving some example circuits for chargers (using their ICs of course).
http://goo.gl/scTIG
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Ian 100,000 lemmings can't be wrong!
14-08-2011, 06:22 AM
I have the same issue with this type of battery - in that they get really hot when they charge. I have often wondered if this is "normal" and take care only to leave the charger plugged in and charging batteries when I am in and also not at night.
They are SONY batteries in a SONY charger - they get almost too hot to touch. Richard.
14-08-2011, 07:12 AM
(10-08-2011, 10:13 AM)Ian E G7OLT Wrote: Here's a link to a useful .pdf document from National Semiconductor detailing the differences in charging requirements for NiCd, NiMH and Li-Ion cell types and giving some example circuits for chargers (using their ICs of course). That's a really useful link Ian - a very comprehensive, well illustrated and informative 17-page article, including details of how to bild the most appropriate chargers. I've printed in off - it's definitely a 'keeper'! I use nicads in things like my PC wireless mouse, and they get quite warm to the touch, but I wouldn't say 'hot'. I've also recently bought a dozen 2800mAH NiMh AA cells for my son's R/C boat, which came with a trickle charger, and they too get quite warm. I'll look forward to studying the article. Thanks once more for the link Ian. David
04-12-2011, 06:52 PM
Are those batteries labelled 'Vapextech Instant' with a silver and pale green body? This is the type that retains most of its charge and can be used after being left in a drawer for a year.
For me anyway, this type definitely gets warmer when compared to other makes when left charging overnight. I've never experienced a problem and have slowly changed over all my batteries to this type as the others have been discarded because the ordinary type cannot be left for weeks then used without without charging them. |
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