I want to create a battery monitor, that will use an LED to display the voltage of a sealed lead acid battery.
The device must light a series of LEDs (or extinguish LEDs, either is OK) when the battery voltage drops below 10v (roughly). I'd like to avoid using a PIC and regulator, as I'm hoping to do this with only a few components. I'd like to avoid any ICs if possible, but if I had to I could use an op-amp.
I'm more into digital design rather than analogue, so can anyone lend a hand? Possibly something using a zener and transistor? Something along these lines: **broken link removed**
I'm thinking of using a chain of resistors to divide the voltage up, then using transistors to monitor the voltage at each point along the chain. (See attached schematic). I'm not sure that idea would work, and it would certainly use a lot of components. Can anyone think of a better way?
Andrew