Super high output (~20A) cells?

[Jarl]

I'm looking for something capable of supporting 12V, 18A. Must be relatively small, low self discharge, long service life and good temperature tolerance, and stable! Capacity, if it lasts 2 minutes at that current draw it's more than enough, 30 seconds will be adequate. (300mah?)

Less cells the better, though I expect to need more than one.

I'd like to say cost not an issue, but lets cap it at about $30 for a single set of cells.


Idea's? The only plan I have is to run 3 LiMN 16340's ridiculously over spec and throw them out after a few runs.... The 26500's could handle it, but I couldn't justify the outlay considering how little use they'll get (once, twice a year?)- size is also an issue.

 

[divine]

Maybe do series/parallel with LiMn. 6, two sets of 3 in series... ran in parallel. That way each sell would only see 9 amps and it would give you twice the capacity.

 

[Turbo Guy]

4 LiFePO4 1100 mAh A123 Sysytems cells or 4 LiFePO4 1250 mAh K2 Energy Solutions Systems could do it and do it for hundreds of cycles no problem but cost will be more like $50 .

 

[Jarl]

More than 5 cycles will quite frankly be a waste of money; I'd much prefer something smaller, because size is a major consideration.

The thinking is, use these batteries to power the horn on my motorbike. Someone tries to start it without the correct technique, horn goes off until battery runs down, by which time the chavs have long since vanished into the distance. I come along a little while later (either running full pelt towards my baby or a couple of hours later, oblivious to anything happening) and replace/recharge the cells.

 

[Jarl]

ok, just dropped a couple of PM's to AW, apparently the LiMN can handle a burst of 20C (constant discharge 8C or 10C), so I'll be ordering 4x18500

 

[mdocod]

ok, just dropped a couple of PM's to AW, apparently the LiMN can handle a burst of 20C (constant discharge 8C or 10C), so I'll be ordering 4x18500

If the point was to get some cycle life, operating LiMn cells at their absolute maximum ratings will not generate the results you desire. A small pack designed to do what you want to do is much better built from A123 or other high current rated LiFeP04 cells.

 

[Jarl]

If I get more than 10 cycles, they're wasted on me. I don't expect to need more than 3

 

[rizky_p]

1. Using RC Lipo pack they are rated for 20C continuous discharge the more expensive one can do more, but RC Lipo pack need a charger with balance connector. Using Nimh in paralel is probably easier. RC grade Nimh like Elite can do 20C without sweating.

 

[Jarl]

1. Using RC Lipo pack they are rated for 20C continuous discharge the more expensive one can do more, but RC Lipo pack need a charger with balance connector. Using Nimh in paralel is probably easier. RC grade Nimh like Elite can do 20C without sweating.

I'd need 10 (probably more, not sure how much they'd sag) 1.2V cells for this application, unfortunately. Volume is a pretty important consideration.

 

[LuxLuthor]

Yeah either AW's IMR or one from any of these sources. Note the Voltage drop with increased amp demand.

 

[rizky_p]

I'd need 10 (probably more, not sure how much they'd sag) 1.2V cells for this application, unfortunately. Volume is a pretty important consideration.

Then Lithiums are better alternative just like the one on LuxLuthor test, Go for AW's LiMn batteries they are good and cheap.