[willy]

Hammer from what I know on my equipment, the engine will often produce more juice than is needed by electrical components, my fishfinder tells me how many amps/volts are on line when it's running. The equipment should have a regulator on it to prevent over juicing and there should be an in line fuse also to protect it from excess and spikes which all systems occassionaly produce.
The one to ask is Franco, among his many attributes he is real good with 12volt systems and can tell you what to check or whether you ca ignore it.