I have a DC-DC convertor (B1205LS/D-1W) that takes 12V (10.8V -> 12.3V) and outputs 5V.
I would like to use this to power my ciruit from my vehicle battery.
The car battery Can go as high as 15V (I`ve heard) and while charging is roughly 14V and normaly 12V.
Can someone suggest a simple method to ensure/limit the Voltage to 12V?
I looked into a 12V zener but I belive for this to work adaquatly you need to have a few volts above 12 always and the battery will sometimes be 12V only.
Are you asking how to reduce the battery voltage so that it doesn't damage the switcher? The car battery will get to ~14.5V with the engine running/alternator charging. The data sheet I looked said it will take up to 13.3V, so put two silicon diodes in series, cathodes toward the switcher, in the positive lead. Since the switcher is ~85% effecient, the current drawn by the switcher should be 1/(5*0.85)*(5/12) = 0.1A so 1N400x diodes will work fine.