Just put a new yellow-top in the Disco today; bought the 34/78 (top and side terminals). My intention was to power the winch from the side terminals and the starter/ everything else on top, but the paperwork that came with it said DO NOT use the side terminals to power a winch. Any idea why not? I just thought it would clean things up a bit.

 

Well, if they let you run a starter off the side terminals, then re-cable and pull winch from top. Alternator runs most things in the truck, puts some amps back in the battery, tapering down to 5 amps or less. But that starter can pull 300 amps plus for a very short time.

 

Yeah, most batteries are like that, the side terminal bus is smaller.
If you'd bought a Sears Diehard Platinum (much better battery made by Enersys), you can power a winch off the side terminals or top post. Both will handle the full load.

 

Where I live, one of the battery stores sells the Odyssey cheaper than sears sells the Diehard Platinum. Only about $5 cheaper, but I will still surprised. I called another battery store, and it was about $100 more than sears.

 

The Marine battery has marine terminals on top that you can use for your winch.

 

I have run my 9500 HSI Warn winch of the side terminals for nearly 10 years now with no adverse effects. Yes I am aware that most battery companies make the same statement.
If there were to be a concern, it would be if the side terminal and supply enough amps for mutiple pulls with out over heating the winch motor and mine has never over heated and gives a full pull every time I have needed to use it.
Just my 2 cents worth.