Trust me just ONE of the ones I use is way more than enough, and they use 737 milliamps when tested.
I put one on top of my 12v 3ah test battery, that I use for projects, and was able to read a book from the light reflected from the white ceiling quite easy, the light was about 1 foot above the table surface facing straight up.
If you want I can take some piccies and email them to you ?
tabetha