Battery Amp Throughput

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lordraiden

lordraiden

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Jan 24, 2013
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Hi all. I'm not sure if someone else has already done this, but I came across something very interesting tonight. I was in the middle of doing some electrical experiments on some other things when I came to the realization that I could amp test the various AAA-D batteries I had on hand. So, just on a whim I tested them. I know it's been a common theme (at least from what I've seen) online for people to ask "How many amps can xx battery produce?" Well, here's the numbers, and this is an average across brands of similar chemistry, so don't get too excited reading this. It's just the "average" based on the cells I had on hand. If someone wants to test other batteries and chemistries, feel free to. Here's what I have so far.

Alkaline:

AAA - 0.6amps (yeah, no joke. kinda suprised me)
AA - 7amps (this one surprised me the most.)
C - 3amps
D - 3amps
9v - 4amps (yes, it can do that much, but it attenuates pretty quickly down to about 2 amps, probably due to the low amp hours)

Lithium:

AA - 6amps

As I said, that's all the batteries I had to test, and if someone else wants to test other battery chemistries and sizes, feel free to post them here as I'm simply sharing what I've found in hopes that it'll help someone else. :)
 
These are direct shorted with a multimeter and you are just looking at the number?
From fully charged batteries?
 
Yeah, these all were dead shorted through a simple amp meter, so what you're seeing is the absolute maximum amount of amps each cell can give off. Probably more realistic numbers would be about 20% less than that. But yeah, as for the numbers I thought they were a little off center myself so I retried and retried, did different cells, etc, and it was a consistent number across every test. So yeah, this is what I got. If someone wants to try this experiment and compare notes, I'm game. I'm not trying to push a particular idea or anything. I'm just tossing out what I found.
 
Not questioning your figures, just thought a D would have lower internal resistance than a AA, I would have gambled on the figures being reversed.

Norm
 
I'm as surprised as Norm!

I've got a 26500 IMR cell I'd like to test, but I don't want my multimeter to catch fire :devil:
 
So was I! That's what threw me. I figured that greater AH would mean greater total available amps of output. But I guess not! I don't know. It might have something to do with the fact that the AA's I have are the kind of Alkalines designed for high drain devices, whereas the D's are for much lower drain. I can't say that's the reason, but that may be part of it. I wonder what something like a normal Everready or some other brand like that which is focused more towards normal drain stuff like flashlights and such would do.
 
This is bad practice. You should not be doing this to cells. I could leave thread alone and mind my own business, but you have encouraged others to do the same and post results.
Battery testing is better done by applying a load to simulate use and measuring the volts under load.
That will provide a useful result relevant to application.
Your tests are useful if you are stranded in the bush and want to start a fire using cells.

Please everyone,unless you are qualified or know what you are doing, don't go shorting cells!
 
lol. Calm down Chodes. I'm not doing anything more than looking at theoretical limits and seeing what they are. I even said that these are the dead short numbers (Isc) and not the max current under load (Imp). The point of what I was doing was more to answer at least one part of a recurring question I've seen others post, namely what the max output of various cells were. If you want raw numbers under load, a good ballback figure is to take the max load and times it by 0.78 and you'll get the max throughput under load. Yeah, that varies per cell and situation, but it's good enough for what most people need. Anyways, just relaying some numbers to satiate some curiosities I know are out there. :)
 
Norm said:
Not questioning your figures, just thought a D would have lower internal resistance than a AA, I would have gambled on the figures being reversed.

Norm
Click to expand...

From what I've always heard, alkaline AA and D batteries are pretty even when it comes to internal resistance. With D batteries, you just get more capacity. This is why, when Coast made the $49 HP550 XM-L light last winter, it used 9AA batteries in a 3s3p arrangement rather than than 3D cells. Doing so not only keeps the 'per cell' current draw down. It also allows for a higher current draw, a higher voltage with a given current draw, and a higher overall capacity (since, even though capacity is lower than with D cells, the lower draw more than compensates). This is basically what Coast told me when I asked them why that light doesn't use D cells. Of course, things are VERY different with NiMH. But in the case of the HP550, the light was not designed around NiMH (even though it works just fine with NiMH).
 
lordraiden said:
lol. Calm down Chodes. I'm not doing anything more than looking at theoretical limits and seeing what they are. I even said that these are the dead short numbers (Isc) and not the max current under load (Imp). The point of what I was doing was more to answer at least one part of a recurring question I've seen others post, namely what the max output of various cells were. If you want raw numbers under load, a good ballback figure is to take the max load and times it by 0.78 and you'll get the max throughput under load. Yeah, that varies per cell and situation, but it's good enough for what most people need. Anyways, just relaying some numbers to satiate some curiosities I know are out there. :)
Click to expand...

Chodes makes a good point, that I was sarcastically alluding to in my last post in this thread - shorting cells is a) not the best way to measure their maximum output and b) if they're anything other than a cheap alkaline likely to result in, at best, spectacular equipment failure, or at worst, Darwinism.
 
StorminMatt said:
From what I've always heard, alkaline AA and D batteries are pretty even when it comes to internal resistance. With D batteries, you just get more capacity.
Click to expand...


D cell are not good at high current, but they do have more capacity and will last much longer than a single AA, more like four to five AA at the same current.
 
Agreed on the runtimes. The part I enjoy most about D cells is how, if you do it right, you can play Peukert's law to your advantage and get some insane amp hours out of them. Case in point. I was doing an experimental D cell powered night light, and using the nubmers I had on hand for power draw of the LED being used, one par of D cells was capable of operating this light, 24/7, for close to 2 1/2 years. Yeah, that long. :D Of course, when your LED's are designed to run on pen batteries, it kinda helps. lol.
 
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