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Author Topic: NiMH versus NiCad Batteries for HT's  (Read 981 times)
N8EUI
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Posts: 146




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« on: June 22, 2001, 02:01:25 PM »

Can anyone tell me the pro's and con's about NiMH versus NiCad batteries?  The NiCad's on my HT are pretty well shot and I've heard about NiMH's but need more info.  
Thanks,
Tom, N8EUI
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KD5MAW
Member

Posts: 75




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« Reply #1 on: June 22, 2001, 02:31:35 PM »

Whatever cons there might be with NiMH batteries have apparently escaped me. What I do know is that my battery-eating IC-W32A craps out about half as soon with a NiMH pack vs. a NiCd pack. It's also lighter with the metal hydride pack installed, which is nice when I have a need to drag it around for hours at a time. Prices are essentially equal these days, so I can't think of a reason to buy NiCd.
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INITZERO
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Posts: 102


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« Reply #2 on: June 22, 2001, 03:40:45 PM »

NiMH batteries are a bit more expensive than NiCad.
Other than that, NiMH is awesome.

I notice the greatest difference in my CoolPix digital
camera. NiCad batteries tend to last 50 pictures
with flash. Alkaline goes for 60 or so pictures. NiMH
will easily take 120 pictures. The difference is amazing.

I guess the other downside to NiMH batteries is that
they don't give much indication that they are circling
the drain. With Alkaline batteries, you have a clear
idea of how much of the battery is left. This is true
for NiCad batteries as well. NiMH seem to have a
charge (in terms of flash recycle time) right up until
they are dead. One minute you have power, the next
you have none.

If the price doesn't scare you off, buy the NiMH and
you won't be sorry.

Matt (k4mls)
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N1GOJ
Member

Posts: 2




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« Reply #3 on: June 22, 2001, 03:52:17 PM »

   Hi,
      I work as a technician for a company that manufacters NiCad, NiMH battery packs, chargers and lighting systems for professional videographers.
Here's my .02 cents...
 
 Pro's NiMH have a higher energy density than NiCad's. of the same size.
Or in other words, a  standard AA NiCad cell has a 600 to 800 mah charge capacity, where as the AA NiMH is usually rated 1500 to 1600 mah.
NiMH don't have a memory problem. (neither do NiCad's
under normal use, but that's another topic for discussion elsewhere.)

Con's NiMH cell life is shorter than a NiCad.
Typically at work, we get our 3.4 ah and 6.7 ah NiMH packs back from the field for service with roughly 300 to 400 cycles on them. (roughly 1.5 to 2.5 yrs) If the pack runs under 75% of it's rated output, and depending on what the customer wants, we recell it or discard it and, replace the pack altogether.  

Our NiCad Packs that are rated at 3 and 4 ah, unless they are misused, go thru 800 to 1000 cycles (roughly 4 to 6 years). on several occassions packs have come back with 1500 or more cycles on them and still run at 90% of rated capacity.

Operating temperature is pretty much the same for both NiCad and NiMH. Under 45 degrees F run times start going down. Also don't try to charging them until they are at least 50 degrees F.  

 If your want to run the HT longer per charge then NiMH
is the way to go.
If Battery life is more important then Nicad is the way to go.

<Rant on>
On another note, Lithium Ion batteries, BEWARE they are VERY DANGEROUS!!!

 Lithium and oxygen are like fire and hydrogen. It's a bad thing. Damaging a lithium ion cell, by overcharging, to the point that it vents, or puncturing the body of a cell or anything that might damage the cell's seal, (including dropping it) will cause the cell to overheat and explode.
I may sound a little nuts, but I've seen the damage done by one sub C size cell. (Just think of a 1/4 stick of dynamite, with shrapnel, and fire.)

<Rant off>

As I said, Just my .02 cents

73 Pete
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WB9YCJ
Member

Posts: 282




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« Reply #4 on: June 22, 2001, 04:04:06 PM »

Supposedly, properly cared for quality Nicads (Panasonic, Sanyo) will provide at least twice the service life of NiMh.  Also, they often can tolerate "some" heat and overcharging. These seem to be the nicad advantages. Price vs capacity seems not to favor either today. You pay appx double for the same physical size NiMh cell which is double the capacity of the same physical size Nicad (half capacity). Clearly, NiMh is superior in capacity and weight.

The problem myself and many others experience with Nicad is that you can buy a set of 1000 Mah "AA" nicads for your favorite portable, and within say six months, they start to behave like 600 mah cells.  I have switched totally over to NiMh due to this.
I prefer having the ability to "top off" my NiMh pack before planned radio usage. I expect having to replace my failed NiMh cells twice as soon as nicads though
(service life).  I dont want to do the math as to which is a better Dollar value in the long run.
Overall, now, I prefer "AA" GE Sanyo 1650 mah NiMh. And, I believe I just saw a 1800 mah "AA" NiMh cell at Dayton.  Check with Mr Yost (Batteries America).


 
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« Reply #5 on: June 22, 2001, 06:54:49 PM »

Good info Pete !

Another good place to readup on NiMh is
www.thomasdistributing.com

many types of nicad and nimh cells.

I have ordered a dozen and a slow charger for use
in my photo flash (six cell power pack) along with
the toys my daughters use.

These cells have paid for themselves twice already !

Now I can afford that new HT !

73 murray
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N6JSX
Member

Posts: 217




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« Reply #6 on: June 23, 2001, 11:01:39 AM »

When I worked at Magellan Systems (1989-1994) as their Sr. Test Engineer I conducted some battery life tests. My results showed that between DuraCell and EverReady Alkaline there was no difference. They both gave nearly 7.5 hours of GPS unit life opearation with a gradual and almost linear voltage role off.

Between NiCAD and NiMH there was virtually no difference in the operational life of the GPS units. The NiMH may have lasted 5 minutes longer over 5.5-6 hours of battery charge life (depends on charge level and how new the battery was). The batteries seemed to hold thier high voltage output nearly level but when they died they fell off steeply from full voltage to almost nothing in 10 minutes.

If NiMH batteries were so great (over NiCAD) I'm sure you would have been seeing more HT batteries converting over. The NiCAD memory issue is real and I'm not convinced that NiMH does not have the same but lesser problem.

But the real improvement to batteries has been the Lithium Ion that you can through in your charger and top of at anytime with NO memory issues. Look at what THEE battery for Notebook computers. There is a reason for it. I just wish MAHA and others would start selling coversion LiION batteries for my Icom BP8/7, BP-200, etc. I would be buying these replacement cells in a heart beat - last longer, can top off with no battery degradation, no memory issues - LiION is the way to go - but expensive.
73, N6JSX /8
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