[Coco] OT: Battery chargers

[Tony Schountz]

OK, then, so I was a bit naive about this. Powerex used to make a universal charger (I forget the model) but they stopped selling it a couple of years ago. The only other smart charger that I have is this one for AA batteries:

http://www.google.com/products/catalog?q=powerex+mh-c9000&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&tbm=shop&cid=5680699528595574563&sa=X&ei=axSaTo3WJ8yatwf48-j_Aw&ved=0CDMQ8wIwAA

It is a lot more versatile, but it is for the 1.2V NiMH cells. Is it difficult to assemble a charger that is taylored to specific applications?

The Rollei battery is remarkably expensive, which why I was hoping to get this one rebuilt with the newer cell technology. 

Thanks for the tips and suggestions.

Tony

On Oct 15, 2011, at 4:09 PM, gene heskett wrote:

> On Saturday, October 15, 2011 06:01:52 PM Tony Schountz did opine:
> 
>> Thanks much for the replies Gene and JP. Here's the charger:
>> 
>> http://www.newegg.com/Product/Product.aspx?Item=N82E16817355042
>> 
> No where near smart enough to charge an NiMh battery correctly.  No thermal 
> controls, possible a flat top detector though, meaning that it expects the 
> voltage to rise slowly, and shuts off when the voltage no longer rises 
> between sample periods.
> 
>> I have 9V connector with wires from the charger to the battery pack.
>> Here are the cells that are in the pack:
>> 
>> http://www.batteriesinaflash.com/assembly-cells/nimh/2-3a/2-3a-rechargea
>> ble-battery-1400mah-nimh-1-2v-ft-w-tabs
> 
> Doesn't look too bad, but never heard of that brand name.  Tadiran or 
> Panasonic likely a better battery.
> 
>> There are 8 in the pack, which looks like this:
>> 
>> http://www.bhphotovideo.com/c/product/44660-REG/Rollei_66251_Nicad_Batte
>> ry.html
>> 
> $169 ea?  That is about a 1000% markup.
>> Thanks,
>> 
>> Tony
>> 
> There are some controller chips about that are smart enough to autodetect 
> the battery chemistry and act accordingly, but I doubt a $27 charger would 
> sport one of those.
> 
> I would be tempted to repack the box with nicads, and find someone to 
> repair your OEM charger, that could give you better results in the long 
> run.
> 
>> On Oct 15, 2011, at 12:36 PM, gene heskett wrote:
>>> More than likely is is Tony, NiMH batteries have a higher self
>>> discharge rate than NiCads.  Couple that with the miss-match between
>>> the charger and the cells, it could be that they are not being fully
>>> charged.  Most Nicad chargers use a temp switch in the batteries (the
>>> third connection to the charger) which turns the charger off when the
>>> batteries start to heat from overcharge.  No clue how your PowerEx
>>> works.  Web page links?
>>> 
>>> I personally would have put some lithium cells in it, but the charger
>>> MUST be one designed for that chemistry else they will be ruined or
>>> possibly even explode.
>>> 
>>> NiCads are a PIMA, but their relatively low self-discharge compared to
>>> some of the other, higher energy density batteries can be a useful
>>> feature.
>> 
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> 
> 
> Cheers, Gene
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