Re: Info From A Lead Acid Battery On An Engine?

eeboarder wrote:

I am developing a system that is powered from a 12V or 24V lead acid
battery configuration on an industrial engine. These are the same lead acid
batteries used in vehicles. The batteries or battery will always be charged
by an alternator running off of the engine.

Is it possible to get a run signal just from the battery?

Yes and No. It depends on the particular engine assembly.

The PIC24F
microcontroller being used needs to be able to tell if the engine is on or
off. If could monitor the engine operation(on or off) from the power
source, I wouldn't need an additional device to monitor this(oil pressure

The alternator generates the AC ripples which can be seen at the battery terminals. You can even get the engine RPM by that ripples. However this behaviour is stongly dependent on the particular engine and the associated electrics, and this method won't work at all for some engines. So, if your goal is a mass production device, I won't count on it.

Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant