MEXICOWANDERER wrote:
BTW a hot non gear reduction starter motor starting say a 454 Chevrolet engine at 20 degrees can draw in excess of 400 amperes inrush and break.
For What It's Worth: I believe that all over the world engine starter motors are geared down. They connect to a large diameter ring gear that has a diameter much larger than the diameter of a little tiny gear on the starter motor's shaft - hence a healthy "reduction ratio" is, in fact, being used to couple the starter motor to the engine's driveshaft.
The garden-variety interconnect solenoid on our Class C motorhome begun to only intermittently charge the coach batteries a couple of years after we had owned the rig. Sometimes the coach battery terminals had over 14.XX volts on them (from the alternator) right after starting the chassis engine ... and sometimes they showed only the normal 12.XX volts from their own at-rest voltage right after the chassis engine was started.
However, this solenoid always "clicked/clunked" whenever I turned the ignition switch. I figured that the solenoid contacts were closing, but making only intermittent good high-current electrical contact due to the contacts being corroded and/or pitted.
I changed to this solenoid years ago with silver alloy contacts to stop this corrosion and pitting. The coach batteries now arrive at our camp sites nicely and quickly refreshed:
http://shopping.murcal.com/Catalog/Bear-DC-Contactor-Family/114-1211-020;jsessionid=0a010c471f43e3c1a11ecc744d4b88c1f3921dcee21e.e3eSch4MaN4Re34Pa38Ta38Naxf0Sure, this relay costs around $35 more than the stock one Winnebago installed ... but having properly cared for coach batteries that you can rely on for years is priceless ... and having this relay not failing to do it's thing time after time is a step in that direction, IMHO.
