Quikie Eneloop Question

[Databyter]

I was telling FM the other day in a question thread that I had intended to make a mag 458 build based on 16 eneloops (19.2 volts).

He let ne know that that was too much current for Eneloop to handle well.

Can anyone elaborate on what the current limit would be for Eneloop aa's?

This will let me know how far I can go voltage/current wise in some of my light build projects, and where I can use my new favorite battery, and where I will have to take other recommendations.

Thanks in advance.

p.s. the 458 build would need to handle about 19 volts and 9-10 amps.

 

[amigafan2003]

1c is ideal, 2c is fine but I wouldn't go any higher than that.

http://www.eneloop.info/home/performance-details/discharge-current.html

 

[Fulgeo]

Hey Databyter,

A good place to start is SilverFox's thread http://www.candlepowerforums.com/vb/showthread.php?t=79302

This thread will give you an idea of how much voltage sag you can expect and other battery characteristics. With the 10 amp draw of the 64458 lamp your 16 eneloop pack will fall well under 17 volts. The eneloops rechargeable life span will be seriously effected if they are tasked with delivering this kind of load. The stock Mag switch gets a little iffy at 10 amps also. It will work but it is approaching ragged edge and its lifespan will be in question. You really to use a better switch or a FET switch solution. I love eneloop batteries and I have about 50 of them. I have used them in many builds. I have never put them in a build that requires more than about 5 amps. When I ran into this issue when I first started building the higher draw mods I purchased and salvaged the lithium ion cells from Dewalt and Milwaukee battery tool packs. The Emoli and A123 cells from these packs could handle 20 amps and 70 amps perspectively. You are lucky because good quality robust individual lithium ion cells are available now on the internet now, and you can buy them without having to cut apart any battery packs.

Happy Mods!

I was telling FM the other day in a question thread that I had intended to make a mag 458 build based on 16 eneloops (19.2 volts).

He let ne know that that was too much current for Eneloop to handle well.

Can anyone elaborate on what the current limit would be for Eneloop aa's?

This will let me know how far I can go voltage/current wise in some of my light build projects, and where I can use my new favorite battery, and where I will have to take other recommendations.

Thanks in advance.

p.s. the 458 build would need to handle about 19 volts and 9-10 amps.

 

[45/70]

Can anyone elaborate on what the current limit would be for Eneloop aa's?

Your question is, of course, open to debate.

Personally, especially in hotwire applications, I like a cell to hold up 1.2 Volts under the intended load. This would mean the eneloop is great for a 2 Amp load, and maybe 3 Amps. Beyond that, again my personal preference, they just don't hold up well enough. For AA cells, I use Elite 1700's for 2 A+ drain applications. I like my hotwires as white as possible, and yes, I'm hard on bulbs.

Dave

 

[Databyter]

Thanks guys, your responses are appreciated. I have had several recommendations for the 1700's which is counter-intuitive since higher AH batteries that are not eneloop design are out there, but I'm assuming the Elite 1700 aa's offer the right combo of design and chemistry to give me a aa setup to support higher amperage. As far as lithium and others, I'm avoiding them for now because I like the idea of not having to have a gazillion chargers and battery types, of course it is inevitable that I will run into a build I want that the lithiums are just to perfect for (like many on this board) and I'll have to invest in another batt. army.

 

[45/70]

I have had several recommendations for the 1700's which is counter-intuitive since higher AH batteries that are not eneloop design are out there.....

Actually, if you look a Tom's graphs (ignore the chart, just look at the graphs), the eneloop outperforms most of the 2500-2900mAh cells in regard to what I was saying in my previous post. The Elite 1700's do quite a bit better.

Dave

 

[Mr Happy]

Thanks guys, your responses are appreciated. I have had several recommendations for the 1700's which is counter-intuitive

It's not really counter-intuitive. You want high amp loads, which means you need low internal resistance in the cell. High capacity cells have to make all the internal parts thinner and more fragile to squeeze more into the volume. On the other hand, high power cells must be made with thicker and more robust internals, which means you can get less into the available space.

When you want to carry large currents, do you use thick wires or thin wires? And if you look at a 1 lb spool of wire, which has the most turns on the spool, the thick wire or the thin wire?

 

[Bullzeyebill]

You might want to follow this thread re use of eneloops in the USL as put together by js. http://www.candlepowerforums.com/vb/showthread.php?t=229533&page=4 See post 168, and others following.

Codeman will be doing some real world testing upcoming, and the results will be interesting. The Orsam 62138 draws about 9 amps. Tom turned js onto the eneloops after his testing. We do not know how the eneloops will hold up overtime in real world usage, but that is the purpose of Codeman's upcoming evaluation. js did capacity tests, just recently with the eneloops in the USL, and results are 2000+mAh at that high current draw. See last post in that thread.

Bill

 

[Databyter]

It's not really counter-intuitive. You want high amp loads, which means you need low internal resistance in the cell. High capacity cells have to make all the internal parts thinner and more fragile to squeeze more into the volume. On the other hand, high power cells must be made with thicker and more robust internals, which means you can get less into the available space.

This makes sense, thanks.