Author Topic: Digital Works Rezap - Supposed Alkaline Battery Charger  (Read 4314 times)

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Offline kc7wdgTopic starter

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Digital Works Rezap - Supposed Alkaline Battery Charger
« on: April 22, 2010, 06:18:28 pm »
I would love to see Dave's take on this.

[url]http://www.engadget.com/2010/04/21/digital-works-rezap-recharges-disposable-batteries-coming-to-n//url]
 

Offline allanw

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Re: Digital Works Rezap - Supposed Alkaline Battery Charger
« Reply #1 on: April 22, 2010, 10:13:24 pm »
Australian company too!
 

Offline Kiriakos-GR

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Re: Digital Works Rezap - Supposed Alkaline Battery Charger
« Reply #2 on: April 23, 2010, 11:19:59 am »
I have see common batteries to exploded .. because they got " recharged " , just for 1 minute I had them connected with my PSU at 2V DC ( before 20 years ) , so to possibly make them ( help them )  to charge just a bit.

I did not succeed , and left the batteries ( four of those ) in an box ,  in my own room , and fall to sleep .
After  45 Min or so , its one started exploding one by one .  

The first explosion made a strong bang noise , and the positive cap was launched somewhere in the room.
The same happened few minutes later with the second , and then with the third , so I started thinking that was not an random reaction , so I started expecting and the fourth one to follow too, as it did.

I am not aware , of what hack this company found ,  but I am aware, that most disposable batteries follows an very minimum of specs - contraction and chemistry , so the most of them will react with very unstable behavior.

So unstable , that does not worth the risk.
We do have stable and safe  NiMh , why should any one bother to have unstable disposable batteries,
specially next to kids ..          
« Last Edit: April 23, 2010, 11:25:02 am by Kiriakos-GR »
 

Offline EEVblog

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Re: Digital Works Rezap - Supposed Alkaline Battery Charger
« Reply #3 on: April 23, 2010, 02:00:17 pm »
Grr, I hate seeing these things!
Another one:


Alkaline "Rechargers" have been around for quite a while. They started out designed to recharge special Alkalines that are designed to be recharged a few times, Grandcell brand among others were the first. They didn't work that well and disappeared once the Sanyo Eneloops et.al came out.
Then a few companies have bought out these chargers designed to charge regular Alkalines. Most likely some sort of pulsed charging scheme. And I've heard they do actually work, kinda. You can force charge back into an Alkaline cell, in theory, but I'm of the understanding it screws up the chemistry and does all sorts of funny things. I believe the process is grossly exothermic and almost impossible to control too. The result is a f!@#$d up cell that kinda sorta works for a few times with non-repeatable results and random loss in capacity and dropouts during use.
Although to be fair I haven't actually tried one myself. But as always with these sorts of over-hyped "to good to be true" products, if it actually worked well everyone would have one.
I wouldn't mind getting one and dusting off my old battery capacity meter project...

Dave.
 

Offline kc7wdgTopic starter

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Re: Digital Works Rezap - Supposed Alkaline Battery Charger
« Reply #4 on: April 23, 2010, 05:09:27 pm »
I would love to see that and the battery capacity meter project sounds enticing...  ;D
 

Offline saturation

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Re: Digital Works Rezap - Supposed Alkaline Battery Charger
« Reply #5 on: April 23, 2010, 07:11:17 pm »
There is this:

http://en.wikipedia.org/wiki/Recharging_alkaline_batteries

I looked into recharging alkaline years back too, and my experience mirrors the Wikipedia article.  It was somewhat worth it before NiMH cells came about.

The real reason to consider it was high current portable devices that ate these batteries, like early digital cameras.  Now, its moot as NiMH took away all the problems of NiCD, as far as consumer usage that is.


Consider, that if you can get 10x the the charge of a 30c alkaline cell, that's .03 per battery, assuming you only use down to 50% discharge.

On an equivalent NiMH cell, using 1/6 C or so slow charging, you'll get about $3/1000 charges, or about $0.003 per cell.

If you fast charge to 1C or so, you'll get $3/100 or the same as the alkaline, without the hassle of reduced life per charge within a 10 recharge lifetime.

Lastly, alkaline are meant to be used today for low drain, long storage applications, like emergency flashlights.  The last thing you'd want is to use a recharged alkaline with unpredictable total burn time. 



Best Wishes,

 Saturation
 


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