want to read 19 voltages with one arduino mega

Hi,
I want to build a 19x voltage-monitor ( like a BIG "Cell-Log" ) but the mega has only 16 analog inputs.
The voltages can be read one after the other.
Can anyone suggest a multiplexer?

THX
Olaf

The 74HC4067 16-to-1 analog multiplexer might be handy - do 16 signals with that and 3 more analog inputs for the other signals. 4 digital outputs are needed to select the channel from the 74HC4067.

There's a shield with 3 of these on called the MuxShield BTW.

Thanks, that's the chip I need.

Now looking for optocouplers that I can put in series and withstand 150V ( 19x6-7.5V ).

I think you will be better off with a 4051, it is only an 8 bit multiplexer but that is all you need, it is cheaper and smaller.