OK I am in the process of taking over vehicle recovery, and the maintenance budget at work. We have a fleet of 120 or so vehicles. Most of them are diesel truck, with a handful of gas trucks, cars and SUV's. We do have a tow truck which I will be using for vehicle recovery however I have questions about jumping diesel trucks. I am going to make a set of jumper cables from welding lead like I made my dad. I am thinking about making them extra-long something like 20 -25 foot, in case I have to pull up behind a truck or canít get right up to it. How big of welding cable or battery cable would I need if I was going to make cables that long to be able to jump a diesel pickup truck? The ones I made my dad are 8-12 feet I donít remember exactly but they kick butt. My second question is I am thinking about getting one of those jump boxes for boosting / jumping trucks in the lot or for trucks that for some reason I can't get to. I spoke with my uncle and he told me back in the day before those existed everybody just got a high amp battery and a set of jumper cables, it essentially did the same thing. However he said they kept a hand cart with 3-4 batteries wired in parallel for jumping big diesel engines at their lot that had bad batteries. I am considering doing this as I have a bunch of extra battery cable laying around in the garage from a previous project instead of buying a 400-500 dollar jump box. I also have two batteries on battery tenders in the garage for backups to my vehicles. I have been reading on these jump boxes, I do have a small one at the house. Its only 750 peak amps it will jump any of my vehicles well boost them if the batteries are week or low on charge. I thought when I originally purchased it that that meant 750 cranking amps. After some research I have learned that is not correct. These units that have a few thousand peak amps that cost 350-500 bucks may be lucky to push 500 amps. My understanding may start but is not enough to reliably start a diesel engine if itís dead flat. I donít mean batteries toasted I mean good batteries that have for some reason been drained down to ~10v. Most of these jump / booster packs found in auto parts stores are intended to boost week batteries and will not start a vehicle with seriously dead batteries. Anyway with that said would a good solid 750-1000 CCA amp battery and a good set of jumper cables fire up a diesel truck with dead batteries?