On Sun, 27 Oct 2013 07:25:03 -0700 (PDT), Amanda Riphnykhazova
wrote:
WOW is this getting complicated!!!
Yep. It looks simpler if you try to understand how it all works.
So you cant just buy a battery and charge it?
Correct. Different chemistries want different types of charging
systems, charge rates, EoC (end of charge) detection methods, etc.
There's quite a bit of technology inside some chargers to guess what
flavor of battery their expected to charge, but at best, it's still a
guess.
You have to differentiate between different types of NiMH charger
or you will kill the battery? That is AMAZING!
Yep. That's about it.
Especially when Costco doesnt even sell chargers for their Eneloops
(mine are either light or dark blue with no explanation of what is
the difference) and makes no recommendations as to charging.
Costco isn't exactly a full service operation. If you don't like it,
or prematurely kill it for some reason, just take it back and kill
some more cells. Incidentally, the pack of Eneloop batteries I
purchased at Costco did include the proper charger.
http://costcocouple.com/sanyo-eneloop-rechargeable-battery-combo-pack/
Not to mention, how do I figure out how to charge (for example) a
Reyzel without spending a fortune on the tester?
If you can determine the chemistry of the Reyzel thing, you can then
determine if it will survive a fast charge, and select your battery
charger accordingly. I did some Googling and couldn't find anything
on a Reyzel battery.
Also, a discharge tester won't show you how to test the battery. It
will only show the capacity of the cell, assuming that you charged it
correctly.
Or is it generally OK to trickle charge any battery so long as you
dont mind waiting?
Well, the general idea is to:
1. Follow the manufacturers recommendations.
2. Don't overcharge
3. Don't overheat
The problem is knowing when to stop charging which implies that you
need to know the starting SoC. If you discharge a battery to some low
reference point, and calculate how many amp-hrs you'll need to get to
about 125% of full charge, you'll probably do ok with a C/10 charge.
For a 2000 ma-hr cell, C/10 would be a 200 ma charge current for about
12.5 hrs.
However, that's not going to happen in real life. The starting point
might be half charge or even 90% charge. If you apply a C/10 charge
for 12.5 hrs to one of those, you've overcharged the battery. Good
chargers have EoC (end of charge) detection circuits that look for a
tiny dip in voltage when the battery is fully charged. However, they
can be fooled by a variety of tricks, such as trying to charge a fully
charged battery.
In short, you're probably ok slow charging almost any NiMH battery, as
long as you don't overcharge or overheat.
So maybe I DO have to buy Panasonic rechargeables to work properly in a
Panasonic phone, assuming there aren't fakes out there!
I have several older Panasonic cordless phones that use AAA packs.
They've lasted perhaps 6 years per pack in continuous charge while the
handset is in the cradle. The trick they use is that they don't
charge to 100.0%. My guess(tm) is that they float charge to about 80%
of full charge, and stop (based on my measurements of the terminal
voltage). The charging systems seems to be designed for long battery
life, at the expense of talk time. That's quite the opposite of the
usual advertised battery claims, where maximum capacity and extremely
fast charge times, are the norm. With NiMH in a cordless phone, if
you don't fully charge, and you don't go through many charge/discharge
cycles, the batteries can last nearly forever.
Or possibly the trickle charge from the base may well do the trick?
Trickle charge (0.05C) does not work with NiMH because the charger
EoC detection mechanism doesn't work at such low levels and because
NiMH just hates to be overcharged:
http://batteryuniversity.com/learn/article/charging_nickel_metal_hydride
Oh and one other thing, I am not a troll but just checked the charger
I am actually using (and dont remember when I accidentally switched)
but this one IS a NiCAD!!!
Hard to tell what you've done here. NiCd and NiMH chargers are
similar but not identical. If you were lucky and didn't overcharge
the NiMH cells, you're probably ok. If the batteries became warm or
hot during charging, they're probably dead.
So I assume the Eneloops are now dead for all practical purposes.
Anyway I can now stop blaming the remote controller.
A discharge test and graph would show if there's any life left.
Can I buy some sort of aa/aaa trickle charger to do the job in future?
For Eneloop, you could play it safe and get the Sanyo recommended
NC-MQR04 or NC-MQR06 charger. The NC-MQR06 is advertised as a "quick"
charger if you consider:
single AA 1.5 hrs
two AA 4.0 hrs
four AA 8.9 hrs
to be "quick".
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558