Can NiMH and NiCd batteries use the same charger?
I have a charger which was originally untended to charge NiCd batteries.
I want to fully charge some of the NiHM batteries in my solar yard
lights. While the solar charger normally charges them, it likely never
gets them fully charged. I think they should be brought up to full
charge at least a few times each year.
If they need a special charger (made for NiHM), where can they be
purchased? (Such as Walmart, Radio Shack, Hardware Stores, other local
stores), since I prefer to avoid online shopping.
On Tuesday, June 28, 2016 at 10:02:41 AM UTC-7, email@example.com wrote:
I sometimes can be a bit stupid concerning electronics, (if it doesn't work, either it's not plugged in or someone didn't pay the electric bill)
electrons are electrons, no matter what the source.
(unless you're using a positron based battery system)
It depends on what you are expecting from the charger and the lifetime
you expect from the cells ("batteries").
A charger designed for NiCd's will typically *cook* a NiMH cell -- it
just "doesn't know when to stop".
Most (new) NiMH chargers can also handle the NiCd cell chemistry.
A "dumb" charger (i.e., a resistor in series with a voltage source)
will typically cook ANY battery (unless the voltage source happens to be
lower than the cell voltage -- in which case, it simply won't COMPLETELY
charge the cell). Some are timer controlled (they just "charge" for
a fixed length of time and "hope for the best"). Obviously, you can
see how reintroducing the battery tot he charger before the battery
has "worked off" that previous charge will eventually result in the
battery being increasingly (over)charged. Likewise, returning the
battery to the charger after MORE than that amount of charge has been
withdrawn means the battery will never be "topped off".
"Smart" chargers are cheap. Buy one -- or five.
On 6/28/2016 5:16 PM, firstname.lastname@example.org wrote:
You've been given good advice on chargers.
Now, some advice on your objective.
Forget it and go do something you enjoy.
If you insist on charging the cells in THAT APPLICATION twice a year,
use the voltage source and resistor to set the current to about 1/10th the
mah rating of the cells and only charge for 10 hours or so.
You're probably better off watching a fun movie instead.
On Tue, 28 Jun 2016 20:16:55 -0400, email@example.com wrote:
Thanks. That is what I wanted to find out. I'll just get a NIMH charger
for both types. Actually, most of the solar lights I have taken apart
have had NiCd batteries in them. Which explains why they dont last long,
because the NiCd batteries retain memory, and they dont always get
charged fully on cloudy days.
Using the advice from a website that sells these solar lights and
replacement batteries, they have a detailed article that says that it's
best to replace with NIMH. (A little more costly, but much longer life
and they do not have that memory issue).
In many cases the battery costs more than the solar light, so its
cheaper to just buy a new light, but I have a few that I paid bigger
money for, and a few more "fancy ones" that can not be replaced because
they are no longer sold. Those are the ones in which I replace the
One thing I learned, is that to test the fixtures, I can put a standard
carbon zinc or alkaline battery (AA or AAA) in a fixture, to see if the
LED lights. Of course those are not rechargable batteries, so they can
not be left in the fixture. But that's a quick way to test the fixture.
Actually, I have never had any fixture that did not work (except those
that had physical damage from fallen objects or other accidents).
Otherwise, its always the battery that fails.
On Tue, 28 Jun 2016 12:02:13 -0400, firstname.lastname@example.org wrote:
Beware - putting NiMH into older NiCad chargers may fry the
batteries ! .. they may emit a popping / boiling sound and a
certain odor .. not that my wife has ever done that - but ..
read the small print on the charger. I currently use a little charger
that will charge both - not an expensive item at all ..
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