actually in some cases you get about half the battery power.
that 19-15 is if you run each without any of the perks they come with, lighting, sound and so forth.
Realistically you are looking at 10 hours compared to 15
at the highest brightness you get only 3-4 hours of life on the dsi, compared to 7-8 on the dslite.
I don't know about how much brighter it is. Could be the larger screens or smaller battery.
Btw, sleep mode lasts forever, you can get a few days out of it in sleep mode, thats nothing new.
http://www.slashgear.com/nintendo-dsi-battery-life-drops-up-to-50-from-ds-lite-0218027/









