Kaito KA1103
 

matt weber wrote:

Immediately after recharge you can see voltages as high as 1.7 volts per cell, but
it doesn't last long.

Which is why it's a good idea to let a freshly charged NiCd or NiMH
stand for a while to normalize the voltage before using it. This is
especially important for certain voltage sensitive devices. For example,
zapping an incandescent bulb in a flashlight with too much voltage can
shorten it's life. If you have to use the battery immediately after
charging it, you can reduce the over voltage by briefly shorting it with
a wire connected between both terminals.

Kaito KA1103
 

HFguy wrote:


If you have to use the battery immediately after
charging it, you can reduce the over voltage by briefly shorting it with
a wire connected between both terminals.


Now that could be a good way to damage the battery.

Kaito KA1103
 

Ron Baker, Pluralitas! wrote:

Seems likely that those 4 batteries are in series.
When they are in series the voltages add but the
current rating is that of the weakest battery.
(If they are put in parallel they better all have the
same voltage and the current capacities add.)
Your 4 - 1300 mAh batteries probably look effectively
like one 6 V, 1300 mAh battery to the radio.
So 13 hours is probably right.

That seems sensible. After 10 hours of charging, the 1103 registered
max battery charge bars (though granted it might not be 100%).

Kaito KA1103
 

homepc wrote:
Be careful about charging batteries within the radio. It has a dumb charger
only regulated by time. After a few charge cycles your batteries will
probably not perform to their potential. That can be a problem because this
model radio goes through batteries in a hurry. After a while there will
probably be one battery that will not fully charge and maybe another that
will over charge. It's recommended to get a good battery charger.

I use this battery charger:

http://www.thomas-distributing.com/mhc401fs.htm

It's slow charge option is a good match for the Degen 1300mAh batteries that
came with my radio. The batteries won't fry, and each one gets monitored
separately so that all four get a full charge.

I charged my batteries with a dumb charger a few times before getting the
Powerex charger. On the first use with the Powerex charger, I found that
one battery took much longer to charge than the rest. After a few cycles
the charge time evened out amongst the four batteries and I now get longer
playtime.

I actually have the MAHA MH-C204W Battery Charger, also bought from
Thomas Dist, for use with a digital camera I got last year. It only
charges NiMH batteries and only has 2 charging circuits, but I assume
the technology is similar to the newer 401fs. I'll probably end up
charging the 1103's batteries in it as well, but wanted to at least
give it a chance to charge its own betteries since it has that feature.

Kaito KA1103
 

On Sun, 15 Oct 2006 23:34:01 GMT, m II wrote:

matt weber wrote:

First of all it isn't 4 x 1300mah, the batteries are charged in
series. Figure the charginig process isn't 100% efficient, so you
need to charger to about 120% of capacity, however you rarely run the
batteries flat. Long term overchargiing converts water to oxygen and
hydrogen which are vented from the battery, resulting in battery
failure.

I was under the impression that Potassium Hydroxide was the electrolyte
being used, not water...I may be wrong.
The KOH is dissolved in water. When you over charge, it is the Water
that dissociates, ultimately there isn't enough water to keep the KOH
dissolved and the battery is finished.

You need to estimate how far down you are going to run the
battery, Without knowing how it evaluates battery charge, it is hard
to know what 25% really represents. NiCd and NiMh have pretty flat
discharge characteristics, so at the point at which you notice a
significant voltage drop, the battery is pretty much flat

It is better to think the NiMh batteries have a rapid discharge rate and
a flat 'running' range. They hold their rated voltage longer than a lead
acid, but near the end of the capacity, suddenly drop. That is why they
are a bad idea for smoke detectors. You might not be around when they
give the warning beeps.

nimh discharge:

http://snipurl.com/z3f3

Dry cell types have a longer slope of discharge and it starts WAY
earlier in the charge life of the battery. They give you lots of warning
as they approach an inoperative state.




mike

Kaito KA1103
 

craigm wrote:
HFguy wrote:



If you have to use the battery immediately after
charging it, you can reduce the over voltage by briefly shorting it with
a wire connected between both terminals.



Now that could be a good way to damage the battery.

Thus the word 'briefly'.