I used to use Optima batteries on the off-road vehicles we prepare, but the quality seems to have dropped off in recent years and if they are allowed to drain fully, they seldom recover. I now use Odyssey Batteries, which is standard equipment on a lot of military applications. They are not cheap but do the business. Odysseybatteriesonline - Home
I am running 2 x PC2150MJS | ELA02150MJS on the Pacific that have to spin the Ford sabre 250 6 cylinder turbo diesel over in the coldest weather sometimes, and being an old school diesel with no glow plugs, it can take a lot of cranking before it goes. These batteries haven't missed a beat so far.