Not sure why but on a transit bus in Italy every time they pressed and released the brake pedal they saw surges up to 100+ VDC on the 24VDC available at the dash. I think there were electrical solenoids involved. Some of there surges were wide which is why I do not call them spikes. We used seperate lines from the battery with inductors and polyfuses as part of the protection on the front end. There is a specification book available with the types of design parameters you need to consider. I do not remember the title but did see it when working on this project.
Larry

 
> From: "R. I. Nelson" <rindesigns@charter.net>
> Date: 2005/11/15 Tue PM 05:16:42 EST
> To: "Microcontroller discussion list - Public." <piclist@mit.edu>
> Subject: Re: [EE] Semi-Trailer Battery Power Filtering
> 
> 
> 
> Shawn Mulligan wrote:
> 
> >Thanks Larry.
> >
> >------
> >nasty environment. Spikes and long term surges caused by all sorts of
> >things like use of air brakes, 
> >------
> >
> >  
> >
> How do you figure use of air brakes is going to cause an electrical 
> spike?  The only electrical I know of involved is the brake lights and I 
> doubt the will do much spiking.  even the compressor cycling on and off 
> is done with a non electrical  air switch.
> 
> 
> 
> 

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