Why still so many alkaline batteries exist?

Status
Not open for further replies.
Originally Posted By: Cujet
NiMh batteries remain around 1.2 volts during the discharge cycle, and can have as much as 2850 mAH capacity.

Do you own any of these 2850 mAh batteries? How are they performing? What is the actual tested capacity?
 
Originally Posted By: Cujet
All true, but we must also consider that the proper measure of energy density is Watt/Hours.

Actually it is Watt.Hours (watts times hours), not Watt/hours.
 
I recharge my alkalines. Get maybe three more uses. You have to watch the voltage though and when they go over 1.7 throw them out.

If they are leaking under normal use I would bet they were deader than a door nail and should have been removed way sooner.
 
Alkaline's do store more energy than other technology. For example AA NiMH's would last about 10 hours in my Garmin GPS (and I used the highest storage capacity examples available); an pair of Alkaline would last about 30 hours.
 
Originally Posted By: Johnny2Bad
Alkaline's do store more energy than other technology. For example NiMH's would last about 10 hours in my Garmin GPS; an pair of Alkaline would last about 30 hours.

That sounds rather extreme, unless you're comparing some really bad NiMH cells with some really good alkaline ones.
 
Originally Posted By: Quattro Pete
Originally Posted By: Johnny2Bad
Alkaline's do store more energy than other technology. For example NiMH's would last about 10 hours in my Garmin GPS; an pair of Alkaline would last about 30 hours.

That sounds rather extreme, unless you're comparing some really bad NiMH cells with some really good alkaline ones.


Eveready 2100 aH NiMH's and Duracell Coppertops. Although the NiMH's did have quite a few cycles on them, I would buy a new set of 4 every spring and rotate them in; there was never much more than about a 10% difference between new ones and ones that had 200 recharge cycles.

Alkalines always perform better as the steady-state current drain of the device rises (and accessing satellites is a high drain application). Use your NiMH's in devices that have low average drain and they will do much better in comparison. None of that is news; even the battery companies will tell you the same thing.

You can even figure it out by just looking at the batteries themselves ... what is the voltage rating of an AA NiMH? It's not 1.5V as in an Alkaline.
 
Originally Posted By: Johnny2Bad
Eveready 2100 aH NiMH's

Did you ever measure their actual capacity?

From some of the reviews I've seen, they don't hold anywhere close to the advertised capacity.
 
Originally Posted By: Quattro Pete
Originally Posted By: Johnny2Bad
Eveready 2100 aH NiMH's

Did you ever measure their actual capacity?

From some of the reviews I've seen, they don't hold anywhere close to the advertised capacity.


Nice one on the "internet stranger demanding I do a bunch of work" to please them trick. It's a forum. Read everyone's posts and come to your own conclusions.
NiMH AA's from any company will only provide a maximum of 1.25V. It's all in the current draw.

Surprised I didn't get "pictures or it didn't happen".

What any given battery "will hold" is dependent on the quality of the charging circuit. If you buy the $10 charger + 4AA's package at the drug store, don't expect good results with any rechargeable technology. I haven't actually tested any, but I can fire up the Tektronix 'Scope and have a look at the charger waveform, and measure capacity and discharge rates over time fore both technologies, if it will make you happy. When I get a minute, of course.
 
Originally Posted By: Johnny2Bad

Alkalines always perform better as the steady-state current drain of the device rises (and accessing satellites is a high drain application). Use your NiMH's in devices that have low average drain and they will do much better in comparison. None of that is news; even the battery companies will tell you the same thing.

That is exactly the opposite of what I've seen. NiMH is better for high drain applications because it can deliver higher current without its voltage sagging. On the other hand, alkaline battery's voltage will sag a lot when you try to drain high current from it.

http://www.greenbatteries.com/nimh-battery-faq/

nimh_vs_alkaline.gif


http://www.stefanv.com/electronics/using_nimh.html


Quote:
You can even figure it out by just looking at the batteries themselves ... what is the voltage rating of an AA NiMH? It's not 1.5V as in an Alkaline.

The problem is that when you use an alkaline battery in high drain application, its voltage sags very quickly. Refer to the above chart.
 
Originally Posted By: Johnny2Bad
Nice one on the "internet stranger demanding I do a bunch of work" to please them trick.

LOL! I asked a question. If you know the answer, then answer. If not, don't worry about it. I'm not demanding that you "do a bunch of work," but your comparison of 10 hours vs 30 hours sounded so extreme that I thought I'd ask for some further clarification.
 
Originally Posted By: Johnny2Bad
Alkalines always perform better as the steady-state current drain of the device rises (and accessing satellites is a high drain application).

One other thing to note, if a battery lasts 30 hours, then it's really not a high drain application, IMO. And in a Nav device, it's typically the screen that chews up battery more than the satellite communication.

If that alkaline battery had 2500 mAh capacity, then it means that current drain was 83 mA (2500/30).

When I think of high drain, I'm thinking 1A and above, something that drains your battery in an hour or two, not 30, but I guess there is no official definition of what's considered "high drain".
smile.gif
 
Lithiums seem to be the "red headed step child" of the primary battery world, but honestly they are the ideal battery for low drain batteries. They last seemingly forever.

A long time ago, I switched to using them where possible in my manual focus, manual advance cameras-especially in the PX-28 size. In use, the drain is fairly low(often just enough to operate the light meter and a few magnets to trip the shutter), and out of use the drain can be from low to non-existent. I've never seen one leak, and while an alkaline might be good for 6 months and a silver cell for a year, I've been able to get 2-3 years from lithiums.

I consider them well worth the cost in things like smoke detectors also.

They can be pricey in things like flashlights, but there again for an emergency keep in the car unit you can be reasonably certain that it will hold its charge for a while.

They also have the advantage of being super light weight.

There again, going back to my cameras I use alkaline for anything with a motorized advance since that chews up batteries fast, especially the higher speed ones. I've actually rebuilt a few factory Ni-Cd packs-some with Ni-Cds and some with NiMHs-to avoid the battery drain issue. An added advantage of that the lower internal resistance usually means faster speeds.
 
Last edited:
Originally Posted By: bunnspecial
An added advantage of that the lower internal resistance usually means faster speeds.

Low battery IR is pretty significant in camera flashes, too. My external flash takes 4xAA batteries. Recycle time is about half when using quality NiMH cells as compared to alkaline batteries.
 
Originally Posted By: i_hate_autofraud

For smoke alarms and other applications, alkaline is needed to get 1.5V per cell where NiMH or NICADs are only 1.2V, max 1.3V just after charging and they set off the low battery alarm way too soon.

This^.
 
Originally Posted By: Cujet
Originally Posted By: JHZR2
Originally Posted By: i_hate_autofraud

For smoke alarms and other applications, alkaline is needed to get 1.5V per cell where NiMH or NICADs are only 1.2V, max 1.3V just after charging and they set off the low battery alarm way too soon.



+1.

For low power use, an alkaline will deliver around 2600mAh at 1.5V, as compared to 2000-2500mAh at 1.2V for NiMH.

Alkalines have higher impedance, so under high drain the actual voltage and capacity is lower.

Some NiMH have high self discharge. The low self discharge type is great.

They are ever so slightly larger than AAs. I had a toothbrush that woukdbt take rechargables because of that.


All true, but we must also consider that the proper measure of energy density is Watt/Hours. Top shelf alkaline batteries have a linear voltage drop as they are used, down to about 0.9 volts, at which point voltage drops rapidly. So capacity of a AA alkaline is typically said to be 1.225 volts on average, and an mAH capacity 2600, for a max energy of 3.9 watt hours.

NiMh batteries remain around 1.2 volts during the discharge cycle, and can have as much as 2850 mAH capacity. For 3.42 Watt/hour energy.

Close, but not quite there.


You neglect the discharge RATE in this equation. Vterminal=Vopencircuit-Current*impedance

Conduction voltage is huge in a practical circuit, and below some point, the electronics may not support operation.

Case in point, for a 500mA discharge:

img01.jpg


I dont really care about how many Wh I get if its at a conduction voltage/condition that isnt relevant...
 
Originally Posted By: Pop_Rivit
Originally Posted By: Vern_in_IL
Why do people still buy these things?


Why do some people have nothing better to worry about?
Troll perhaps?
 
I've had good luck with Duracell "Procell" AA batteries which can be had in bulk on the "Zon". With LED lights the AA is the new "D".
 
Originally Posted By: Quattro Pete
Originally Posted By: bunnspecial
An added advantage of that the lower internal resistance usually means faster speeds.

Low battery IR is pretty significant in camera flashes, too. My external flash takes 4xAA batteries. Recycle time is about half when using quality NiMH cells as compared to alkaline batteries.


Good point on this.

When I'm doing full power pops, it's usually with Vivitar 283s running off the line voltage so the recycle is pretty quick.

I still have a lot of older thyristor type strobes kicking around, along with the oddball Canon 300TL for use with my T90 and a 580EX for use with newer SLRs/DSLRs(plus it also works great with my T90, meaning if I'm packing film and digital both and want a stobe I only have to take it). In any case, a Vivitar 283 has an ASA 100 guide number of 120(ft) with its standard diffuser(will cover around 35mm lens on a 35mm camera head-on). Guide number specs can be hard to find on some newer strobes since they're a bit antiquated, but some quick reading showed me that my 299T/300TL are both around 100(ft) at 50mm, and my 580ex is close to 200(ft). My much beloved Mecablitz 360, which is the same age as my Vivitars but has a lot more features, is also 120(ft) at the "normal" zoom setting per the calculator on the back(30ft at F4). In any case, as I said rarely do I dump a flash and also usually shoot slow enough that I don't have to worry about recycle time, but the faster recycle is one advantage.

I have a couple of strobes modified to take Quantum sealed lead acid waist packs-I have to admit that one of those would be tempting if I could find a working one
smile.gif
 
Status
Not open for further replies.

Similar threads

B
Best Current Maker of Ni-Cd AA Size Cells
Replies
6
Views
814
y_p_w
billt460
Anyone Ever Had A lithium Wafer Battery Leak ??
Replies
10
Views
908
kschachn
B
Oil not returning to A/C compressor... why?
Replies
4
Views
1K
brages
garageman402
Battery Tender Jr. vs. Noco Genius1
Replies
1
Views
5K
eljefino
Graham Piccinini
Recommend a travel stop.
2 3
Replies
57
Views
2K
gfh77665
Back
Top