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Rechargeable Batteries Revisited


MajBach

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It wasn't until yesterday that I realized how behind the times I am. I had no idea of the new battery technology that was available. Last I knew, Alan Thicke was doing infommercials on rechargeable alkalines. Judging by how long that lasted, it didn't catch on to quick.

Anyway, so I read all the threads here on batteries and such and decided I should catch up with everyone else. I did a bit of research too on the net and couldn't decide if I wanted to go NiMH or rechargeable alkaline. Naturally I like the lower cost of the latter but it was the shelf life I really wanted. Using them in emergency flashlights and remotes etc. NiMH, on the other hand, self-discharge faster than any other but appear to have to longest use and lifetime longevitey.

So I went shopping today, figured I'd go one way or another and to my surprise, I found a Rayovac charger that could charge both types of batteries (even NiCds too - but who cares about them anymore). Even better was that it could charge all sizes excluding 9V (again - who cares) and do as many as 8 AA or AAA at once. The best feature was its cost - $29 CDN, compared to $69 for that one-hour charger from Rayovac.

Dilemma solved, right?

No, I didn't buy the unit because a few things made me suspicious and I was hoping someone here could shed some light.

The unit in the Rayovac PS3. Now, all other units from any company I found that charge NiMH, also charge NiCd too. There is a switch on the charger to go back and forth. This leads me to believe there is a difference in the way the charger charges the batteries. The PS3 had no such switch to distinguish between the two different types. Not to mention the fact that this unit also charges Alkalines, which is clearly marked on ALL other chargers not to mix the two different types. How does the PS3 know what type of battery it is charging? Finally, it also doesn't state in the instructions how long charging should take, which is somewhat important.

Does anyone have experience with this charger or can advise me further on it?

Thanks in advance.

 

MajBach

 

You can't have everything.

where would you put it?

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MajBach, my guess is that the charger in question is a simple "C10" charger, meaning that it charges at a very low rate and requires 10 to 14 hours for a full charge. It's what is known as a "dumb" charger as opposed to a "smart" charger that is electronically controlled. Nearly all good fast-chargers are smart chargers. And yes, there is a very important difference between the charging circuits for NiCad and NiMH batteries. It has to do with the manner in which a full charge is detected. With their higher charging currents, smart chargers need a way to determine when to safely stop the charge cycle so as not to overcharge and overheat (destroy) the batteries. NiCad use "negative delta-V" detection circuitry, and NiMH's use "zero delta-V" detection. (You can charge NiCad's in a NiMH charger, however, you won't get a full charge, but DO NOT try to do the reverse without severe damage. That's why the switch.)

 

Believe it or not, NiCad's still serve a useful function because their self-disharge rate is lower than NiMH's and they are able to handle more abuse. However, for most pratical high-current applications NiMH's are definitely the way to go! My personal opinion is DO NOT waste your money on rechargeable alkalines.

 

Hope this helps. Cheers ...

 

~Rich in NEPA~

 

1132_1200.jpg

 

=== A man with a GPS receiver knows where he is; a man with two GPS receivers is never sure. ===

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Maybe I will go with a just a MiMh or NiCd 'smart' charger. Curious, what would happen if I stuck a rechargeable alkaline in one of these charges OR in one of my old NiCd chargers? If I leave it in for a determined time to avoid damage I mean. would I be able to get away with charging and alkaline battery?

 

MajBach

 

You can't have everything.

where would you put it?

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quote:
Originally posted by MajBach:

Curious, what would happen if I stuck a rechargeable alkaline in one of these charges OR in one of my old NiCd chargers? If I leave it in for a determined time to avoid damage I mean. would I be able to get away with charging and alkaline battery?


 

It probably wouldn't be a good idea. How would you determine the charge time and rate? The biggest problem with alkalines is that they are not good for high current drain applications. In a GPS receiver they could be acceptable, but not for use in a digital camera, flashlight, etc. From what I know, they are NOT good for very many recharge cycles. Good NiMH's can be recharged 800-1000 times.

 

~Rich in NEPA~

 

1132_1200.jpg

 

=== A man with a GPS receiver knows where he is; a man with two GPS receivers is never sure. ===

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Fast charging cells are hard on them and shorten the number of times you can recharge them. With NiMH it not a big factor you probably go from a 1000 times to 700-800 times but it does hurt them. NiCd takes this a lot harder. So if you can afford the time slow charging your batteries is a better way.

 

As for the Rayovac chargers I think there great. And in this case I think you will find that the charger are very smart chargers. By measuring cell voltage and internal resistance you can figure out the difference between a dead 1.5 V rechargable alkaline and a 1.2 V NiMH or NiCd. No switch needed if your smart.

 

The rechargable alkaline are great if you need the 1.5V but you only get 10-20 recharges on them and there performance decreases with each charge. I think the best rechargables batteries out there are the 1800 mAh NiMH.

 

Later

mc

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quote:
We still need the web site of your business. Some of us might want to buy from you!

Ranger Roger:

I don't own a business, I just work at a large sporting goods store in Utah (Sportsman's Warehouse) and I sell GPS receivers and accessories. I really wish I owned this business!

 

7871_200.jpg

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I bought a bunch of 1700 mAH AA and 700 mAH AAA batteries and a Maha AA/AAA charger from Thomas Distributing. I found the link on a thread in the old forums. The prices were good but the web site and the site programming leave a lot to be desired. If you make an order there, just be patient and type everything carefully.

 

http://thomasdistributing.com/batteries.htm

 

-E

 

--

N35°32.981 W98°34.631

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I still cannot decipher this info. I do understand the chargeing and performance capabilties of different batteries. I also want both alkaline and NiMH batteries for different applications. It's the charger I am uncertain about. Check these sites out, look at the PS3 at the bottom:

http://www.rayovac.com/products/recharge/chargers.shtml

 

These are the specs:

 

http://www.rayovac.com/busoem/oem/specs/ren10.shtml

 

And this is it's technology:

 

http://www.rayovac.com/busoem/oem/specs/ren7.shtml

 

And this is general info on all batteries and charges:

 

http://www.rayovac.com/busoem/oem/specs/download.shtml

 

I'm still undecided!!!

 

Any techies care to help?

 

MajBach

 

You can't have everything.

where would you put it?

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quote:
Originally posted by MajBach:

 

I'm still undecided!!!

 

Any techies care to help?You can't have everything. Where would you put it?


 

MajBach, why not keep it simple? Use high-quality alkalines for applications that require one-use throwaway cells (emergency flashlight, other long-term storage devices), and NiMH's for everything else (digital cameras, GPS, etc.). You can't go wrong with the Ray-o-Vac PS-4 system.

 

ps4_group.jpg

 

I'd recommend getting the 12VDC car adapter so that you can take the charger with you on the road. Cheers ...

 

~Rich in NEPA~

 

1132_1200.jpg

 

=== A man with a GPS receiver knows where he is; a man with two GPS receivers is never sure. ===

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