Hi,

what is the max Vin ? according to the site it is 4.5 - 9.0 Volts. But on the card that was in de package when i orderded the Mbed it says: 4.5 - 14.0 Volts ? Wich one is correct?

I just looked in the packing for some of the Mbeds I have. The first two I picked up the card on the inside said 4.5 - 9.0v. However, the thrid one I picked up actually said 4.5v - 14.0v just like yours. All mine are LPC1768 Mbeds so I supposed a correction has been made and it's 4.5v - 9.0v

See here.

Clear now!

I've tested the MBED with 2x 9V battery(parallel) to see how long it will run. Wrote a program that writes a .txt file. So that i can read back later how long it lasted on battery power. Started the run on friday , came back on monday, no more power on the board. Wanted to check the .txt file, but nothings on the board, even the programm is gone. How is this possible?

I know this answer is very late to the time you wrote question. My guess is that the mbed never closed the file as it ran out of power. This is assuming you open file and just star writing every sencond or other time. My suggestion would be to open, write and close the file on every loop, or every few loops. Not the best solution, but easy to implement. The other would be to have it detect a drop on battery and close file (more efecient but more complicated to implement).

Batteries in parallel, hardwired to one another - is an engineering no-no. You need a diode in series with each battery, to the load.

Reason: batteries are never equal/identical; one will pass current to the other to attempt to equalize. This shortens battery life. The diodes prevent this.

Very common issue.