Jeff, I considered the various par36 halogen lamps, but rejected them on tha basis of beam patterns, spot, flood, etc, in favor of the traditional "automotive" spread of the tractor bulb.
The 60w tractor bulbs came to today and I installed them in the stock locations with all the stock wiring. They are dramaticly brighter, and hotter, but all seems well electrically.
They draw a little less than 10 amps as expected, the original 35w lamps draw nearly 6 amps. I suspect the switch is rated for 10 amps or more. The charging system had no trouble keeping up with them. After having them on for several minutes without the engine running, I started the engine. The amp meter went to 20 amps with the lights on but quickly recharged the battery and was at zero in about three minutes.
So the 15 amp rating of the charging system is very conservative, it easily put out 20 amps at 3550 RPM.
I think the only issue at this point is the front lens. It will take a longer test to determine if the 60w lamps get too hot for it. I do have some lexan sheet and plan to make a clear lens as well to test. I will test the whole installation next time I mow to see how everthing does with more extended on times, but I did have it on long enough today to feel comfortable with the wiring and the switch.
There is no rating labled on the switch, but many similar switches are rated bwtween 10-15 amps, and like everything else, there is a good chance Gravely over built this as well.
Another thought I had was to eliminate the front lens all together, and possibly build a metal plate to replace it, moving the par lamps forward and mounting them in holes in that new plate - much like an automotive application. The plate could be painted white and would look similar to the original lens.
This might also be a workable idea for the 800/8000 tractors - make a plate to replace the lens and mount two par36 lamps in it.
If the lamps prove too hot for any lens, I think this is the direction I will go.
Sheldon
