NiMH in NiCad charger?

Gandalf

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What happens if you recharge NiMH batteries in a NiCad charger? What exactly is the difference in the way they need to be recharged? The first set of NiMH batteries I got, from Radio Shack at least 1 1/2 years ago, have been charged only in a NiCad charger. They seem to work fine, giving around 3 times the life of a standard AA NiCad. I purchased an Eveready charger, that has a switch for NiCad/NiMH. Now that I'm getting more and more of the NiMH AA batteries, (Rayovac 1600 mAH AA's from Walmart; $11/4PK +tax)I'll need to get 1 or 2 more chargers. (Probably for AAA/AA only) But I wonder what I may have done to the set of NiMH I've been rechargeing in the NiCad charger.
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vcal

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I don't see anything wrong with what you've been doing, but if I were you I would get a pulse type unit.
That way, you won't have to make a Career out of charging batteries
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and it's supposed to be a lot easier on 'em.
*editorial-I used to hate rechargeables bcos you had to "babysit" them, and wait hours and hours and More hours....
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-I just now put in an exhausted NimH AA-1600mAh, but I will have that battery Back in full service in 90min!
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D

**DONOTDELETE**

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I found that on one type of charger, the NiMH/NiCd switch was just a 'feel good' switch. The idea is that NiCds will accept a higher charging rate compared to NiMHs. The thing was that the maximum charging rate was a fair amount LOWER than the maximum allowable charge rate for the NiMH batteries.

Thus, the switch did nothing at all. I have been charging NiMHs on NiCd chargers for years without problems. I do, however, tend to use a lower charge rate (140 mA) unless I am in a hurry, as I feel that the heat generated by the rapid charger (240 mA) is detrimental to the cells.

Walt
 

vcal

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Walt Welch:
I found that on one type of charger, the NiMH/NiCd switch was just a 'feel good' switch. The idea is that NiCds will accept a higher charging rate compared to NiMHs. The thing was that the maximum charging rate was a fair amount LOWER than the maximum allowable charge rate for the NiMH batteries.

Thus, the switch did nothing at all. I have been charging NiMHs on NiCd chargers for years without problems. I do, however, tend to use a lower charge rate (140 mA) unless I am in a hurry, as I feel that the heat generated by the rapid charger (240 mA) is detrimental to the cells.

Walt
<HR></BLOCKQUOTE>

Not necessarily an argument with that, but on the newer rapid-pulse units I've been using, the cells are always only mildly warm when they're through charging.
(The included manuals mentioned thermal detection circuits, amoung several other protective features...
-That's probably why these type chargers are noticeably more costly.
BTW-I've been able to save about 20 batteries, using this device,
-that I would have had to throw away otherwise.
 

cave dave

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I was wondering if it was a good idea to run a fan over the charger while charging batteris? It does keep the cells significantly cooler. Or at least the outside temp, not sure about the internal temperature.
 

vcal

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by cave dave:
I was wondering if it was a good idea to run a fan over the charger while charging batteris? It does keep the cells significantly cooler. Or at least the outside temp, not sure about the internal temperature.<HR></BLOCKQUOTE>

Sure wouldn't hurt matters.-As you know, too much heat sure doesn't help rechargeables...
-If those batts. are hot to the touch-(I occasionally check 'em on my inner forearm), a small fan sounds like a good idea.
 
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