boez52

What is the max current the 5V pin can handle when powering the board from it?

Ok, I meant the battery name/type, although the chemistry is also helpful. Just for verification, is it really 5400 mAh? Because I could not find any NiMH AA cell with such capacity, they are usually less than 3000 mAh; also from your measurement 150 mA * 10 h = 1500 mAh, which seems more likely.

They are AAs by Sanyo with a capacity of 2700mAH... I have two packs of 8 cells. The two packs are each in series with a diode then the diodes come together to the same node to create a diode-or.

Could you share the battery type (to get its discharge curve)?

NiMH

NiMH

How exactly do you have the batteries connected? What other devices are connected to Netduino, if any? From your description it sounds like the batteries are discharged very quickly, which can be caused by a short circuit or there is a device that draws too much current.

The batteries are in series with a capacity of 5400mAH. Nothing is connected to the board but a LCD and some thermistors. I measured the current of the whole system and it draws 150mA. The batteries should last for more than 24hrs but I only get 10hrs.