What's the difference between Alkaline & Rechargable batteries?

Fuzzmuncher

Platinum Member
Oct 15, 2000
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Why do some devices say Alkaline batteries only? For a given size(i.e. AA batteries), is there really a difference between output of rechargables & alkaline?
 

StageLeft

No Lifer
Sep 29, 2000
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Rechargeables are either the old crappy Nickel Cadmium, or the newer Nickel metal hydride. NICD have crappy longevity. I think they have a good voltage output, but die soon. NiMH have 1.2 (although an AA alkaline has 1.5, it drops to 1.2 quickly, and then holds around there), so they're basically the same as alkaline, although they last much longer in high-drain devices (in a remote controller they'll last less because they lose 1-2% each day sitting there, but if you use them relatively quickly, like in a discman, they'll go 3-4x as long as an alkaline).

I think lithium ions are rechargeable, but I know nothing of them.

Anyway I think anything that says "alkaline only", basically means "don't use a crappy old NICD", because it won't last long at all :)
 

NutBucket

Lifer
Aug 30, 2000
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Usually just means the device will run longer on a set of alkalines then rechargables. Of course, there are rechargable alkalines;)
 

Heisenberg

Lifer
Dec 21, 2001
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Alkaline batteries run down differently than the Nicad ones do. Nicad tend to have a fairly constant voltage right up under they die whereas alkaline decrease over time. That and nicad have a slightly lower voltage than alkaline. I'm guessing that has something to do with it anyway.

Edit: Had nicad and alkaline backward. :eek:
 

StageLeft

No Lifer
Sep 29, 2000
70,150
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Oh yeah you can get rechargeable alkalines as well, but in a high drain device nothing beats a lithium ion (unlike NiMH they don't have a short shelf life) or a NiMH.
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
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There are a lot of differences. The biggest being that you can reuse one, and not the other. :p

Heis: That's not necessarily true.. a good NiMH will have a nice stable voltage curve right up until the battery is dead, where it falls off like a rock...

Even though their cell voltage is less, NiMH batteries have a far higher power density than alkaline batteries.

But what Skoorb says is true. Rechargable batteries lose their charge orders of magnitude faster than an alkaline just sitting, so they aren't good candidates for things like clocks, remotes, etc..
 

Heisenberg

Lifer
Dec 21, 2001
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Originally posted by: Eli
Heis: That's not necessarily true.. a good NiMH will have a nice stable voltage curve right up until the battery is dead, where it falls off like a rock...

Edit: n/m - I'm retarded. I had the behavior between nicad and alkaline backward.
 

Fuzzmuncher

Platinum Member
Oct 15, 2000
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nimh

One of my dive flashlights takes 6AA batteries. Usually it works okay when I use rechargeables, but there are occassions when it just dies for no reason with new batteries. I was wondering if perhaps the voltage difference had something to do with that?
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
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Originally posted by: Fuzzmuncher
nimh

One of my dive flashlights takes 6AA batteries. Usually it works okay when I use rechargeables, but there are occassions when it just dies for no reason with new batteries. I was wondering if perhaps the voltage difference had something to do with that?
New alkalines, or freshly recharged rechargables?

If it's the latter.. you probably have old sh!tty batteries and/or charger..;)
 

Fuzzmuncher

Platinum Member
Oct 15, 2000
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Rechargeables. I haven't had a chance to take the lights out again with all alkalines. If the swell goes down, I'll probabaly go dive this weekend.

I have about 50 1800 AA batteries I picked up from a hot deals on this forum about a year ago - green color ones. They work great for about everything else. :(
 

RossMAN

Grand Nagus
Feb 24, 2000
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Originally posted by: Fuzzmuncher
Originally posted by: RossMAN
If this is for a camera you really should invest in good quality rechargeable batteries.

Places I would recommend buying from are:
Thomas-Distributing.com
Sunn Battery

Thanks Ross, I'll probably ditch my batteries/charger & go with a thomas-distributing package.... I'm just wondering if it's the batteries or the device setup?

You're welcome.

I would first read this and buy either the MAHA MH-C401FS or MAHA C204F charger kits.