Hi, I believe the recharging time according to this review (http://northernreviewer.com/sandberg-o...) should be around 10 hours. It is not the same model but its for the same brand and looks similar, just different battery capacity. I think this works completly if you are out in the wild and you can leave it outside all day and then use it overnight. You definitely not gonna get fast recharge times with the sun...

at 400 mA to reach 24000 mAh it might approx. 60 hours. if you have sun light for 6 hours a day, that will take 10 days. :-)

No, unfortunately the manufacturer doesn't provide this information.