LED Battery

[Jon86]

I'm looking for a battery to power a 3.6V 3A Cree LED for roughly two hours or so. Can anyone suggest the cheapest way to do it?
I was thinking of maybe Lead acid, but that seems a little expensive. Weight doesn't matter, just price really.
Any help greatly appreciated, thanks. 

[ddavidebor]

. Weight doesn't matter, just price really.

Lead acid car battery

No dubt

[echen1024]

Lead Acid. Cheap and has a lot of capacity.

[mariush]

I agree, lead acid battery would be the easiest followed by maybe one of those lithium batteries for toy airplanes .

Cheaper... and I'm not even sure it would be cheaper....

maybe one of those laptop batteries you find on eBay cheaply?

maybe if you go and buy 20-30 alkaline AA batteries and put them in series and parallel so they would share the current?  See http://www.batteryshowdown.com/results-lo.html and http://www.batteryshowdown.com/results-hi.html  ... they last hours at 200mA draw and about half an hour at 1A...

[Fsck]

Lead acid if you have to buy.

However, you may be able to find thrown away busted laptops and salvage armies of 18650 cells which would be free.

[Jon86]

Lead acid seems a little expensive really, to get a good 6Ah one will cost £10, then I'll have to somehow regulate that voltage down for the LED, that costs more...
The 18650 cells sounds promising, which laptop batteries would contain them?
Also, what type of lithium batteries for toy airplanes?

Thanks for the help, I'll get back to researching 

[Psi]

One cell hobbyking (or other) lipo and a large wattage resistor.

The brightness will fade though, as the resistor will be spec'ed for 4.1V and the Vbatt will drop as it discharges

[ddavidebor]

Lead acid seems a little expensive really, to get a good 6Ah one will cost £10, then I'll have to somehow regulate that voltage down for the LED, that costs more...
The 18650 cells sounds promising, which laptop batteries would contain them?
Also, what type of lithium batteries for toy airplanes?

Thanks for the help, I'll get back to researching 

Well you should use a regulator anyway.

Lead acid are simple to use and charge, litium need a proper charger or they became quite dangerous