AA Alakaline battery's max amperage?

[gav6280]

What is the maximum amperage 3 alkaline AA cells in series can continuously produce?

What about the newer no rechargeable lithium based battery's?

And what is cell resistance?

Thanks.

 

[Mr Happy]

What is the maximum amperage 3 alkaline AA cells in series can continuously produce?

For how long? There is an infinite number of answers to this question depending on what run time you consider acceptable. The capacity of an alkaline cell varies by a ratio of 10:1 or greater depending on the load you place on it and the lowest voltage you will accept while considering it useful.

But a rule of thumb is 1 amp max for short run times up to an hour or so.

 

[gav6280]

Im asking because ive taken apart my ultrafire w200 with a view to changing the R2 Led that it comes with to an XPG.

Its a direct drive torch with no resistor or anything. It uses 3 x 1.5v alkaline cells, and i was concerned that this will be to much for an xpg due to lower fv required.

I need to get this sorted and don't want to kill my only xpg i have left in stock. And don't want to mess about with installing a diffrent drive if i really dont need to.

Hence my question, so if a Duracell alkaline AA cell is only capable of outputting a maximum of around 1000ma then there is nothing for me to worry about?

 

[Mr Happy]

OK, now you have clarified the question with more information, the answer is different. Three series AA alkaline cells will easily produce more than 1000 mA for short periods if you ask them to. They just won't have a very good run time. However, the run time might be long enough to damage an LED emitter.

I'm afraid I cannot give you an answer about whether it is safe to do what you propose because there are too many variables involved. The Vf of the LED combined with the internal resistance of the battery might limit the current to safe levels or it might not. An experiment would be the only sure way to find out.

What I can tell you is that by normal design guidelines you would not want to draw more than about 750 mA continuously from an AA alkaline cell while still achieving a reasonable run time. Alkaline cells are not the most suitable for high current loads.

 

[gav6280]

Well it comes as is completely unmodified with an XRE Q5, no driver or resistor or anything, and i was hoping it would be a case of simply swapping the LED and optic?

If an xre would run in there happily then surely an xpg would be ok too?

 

[Magic Matt]

Forgive me if this is a stupid question, but why use Alk batteries and not NiMH? I believe they handle current better for longer, and my reasoning there is also that the lower voltage might suite the LED Vf better.

 

[lolzertank]

If an xre would run in there happily then surely an xpg would be ok too?

Not true. Since the XP-G has a much lower forward voltage, it will draw considerably more current from similar cells.

 

[gav6280]

Forgive me if this is a stupid question, but why use Alk batteries and not NiMH? I believe they handle current better for longer, and my reasoning there is also that the lower voltage might suite the LED Vf better.

NiMH,i don't have any and i don't like em....

 

[joeparker54]

what's not to like????:thinking: smoother output voltage, more cost effective and environment-friendly, higher power capacity, oh and they don't leak nearly as often.... you're right, NiMH sux:sick2:

BTW, three L91's in series will put out over 4V under load and waaay to much current for DD setup.

 

[gav6280]

Thanks for your input, but for several reasons relating specifically to the environment its to be used in. nimh cells are not really an option in this case....

 

[Bullzeyebill]

Got to respect the OP's position on Alkalines vs NiMh. It is his thread. Mr Happy has the answer. If you want to safely run an LED with three Alkaline batteries then try to match the vf of the LED with the voltage of the Alkaline's, knowing that there will be some voltage sag under load. Wayne at Elektrolumens for years built LED flashlights setup for three Alkalines, and sometimes he added a resistor to drop the current to the LED, when he used low vf LED's. One of my best lights that works perfectly with 3 Alkaline's or NiMh's is my Elektrolumens FT3C.

Bill

 

[Magic Matt]

You really have peaked my curiosity now... an environment where Alk is better than NiMH? I'm still new to all this and keen to learn... are you able to explan why?

 

[Bullzeyebill]

You really have peaked my curiosity now... an environment where Alk is better than NiMH? I'm still new to all this and keen to learn... are you able to explan why?

Ok to ask this question as long as it is not set up to bait the OP, though it is sort of off topic. He is interested in max amperage using AA Alkaline batteries.

Bill

 

[gav6280]

You really have peaked my curiosity now... an environment where Alk is better than NiMH? I'm still new to all this and keen to learn... are you able to explan why?

Underwater cave exploration!!

Its actually safer if you can see the gradual drop in light level rather than it just getting a lot dimmer in big stages or even go out altogether if youu using protected 18650's.....

And the main one is that charging of battery's is often not possible on remote trips, so its logistically easier to take Alkaline disposables.

 

[Magic Matt]

Ahh I see! 😀

Thanks for enlightening me (sorry, bad pun).

Thinking aloud... That makes me wonder if underwater lights could have a nice battery level indicator (though I suppose that could be overlooked easily), or some sort of "high-low-high-low" pulse periodically when the cells are nearing the end of their life. All extra electronics and complexity though, so I can understand why you would want to avoid it.

 

[gav6280]

Exactly all of your backup lights need to be as totally bare bones as possible, no electronics, switches, buttons or any parts strictly unnessceary.

 

[Light Sabre]

I ran some battery tests 2 or 3 years ago with AA batteries using a 2 ohm resistor which would give you 3/4 amp initially and would more inline with what you are doing. All times were continuous until an individual battery reached 0.9 volts. All times are in hours. Here's what I came up with:

Duracell Ultra MX1500:_______ 2.91
Duracell CopperTops MN1500:_ 2.68
Energizer Max E91: __________2.33
Rayovac 815 Alkalines: _______1.76

The best alkaline battery then would be the Duracell Ultras. I haven't tested their new version, but they're supposed to be better. Find out what your maximum current would be. Do the math in relation to the above times and round down to the nearest quarter hour. That should give you a good safety margin I would think. YMMV

If you can switch to D batteries then your runtime would be approx 5+ times the above. Can only find the data sheets for my rejected brands. It would be a lot bigger flashlight tho.