So, I was waiting for a new 3DS game to play and went back to the DSiXL to play DQMJ.

On Aug23 morning, I closed the lid and left it unplugged with the game still on after using it for 2 hours-ish.

It's now Aug27 and it's still on. How much longer will it last?

The only way I think it can last that long is if the brightness is at it's lowest. Sometimes I play my Dsi (Not XL) before I go to sleep (At full brightness). When I get tired I close the lid and leave it next to my bed. When I wake up I find that it either off or at low battery.

guys sleep mode uses minimal battery. My 3DS with Wifi/spotpass and pedometer goes over a day in sleep... with only memory backup, the DS it should be able to last way more than just a few days.
(and screen brightness has nothing to do with it... the screen is turned off when you close the lid.

^DSL can last for up to 8 days.
That is impressive engineering.

dang 8 days? impressive.

I have definitely kept mine on longer than 8 days in standby and still had it have battery left. It is a fairly big machine, so they can dedicate a much larger amount of the internal space to battery, on the smaller models, the chipsets will take up larger space.

Aug 31, and it's still kicking.

DSi XL is my favorite DS model. For those out there comparing it to the DSi, the battery life is actually better on average.

Pretty impressive on the stand by. I wish they could get a battery to run a hand-held at max settings for 14+ hours. Although it isn't that big of a deal to recharge after 6-8 hours of gaming.

Sep 2nd and it's still going.