Batteries

If your in cold weather,,, get the biggest dang battery you can find... your grid htrs will pull 240amps when heating, on a battery with 750CCA which is Cold Cranking Amps @ 32*F you have now come down to 450 usable amps at 32*F...... yes you have dual batteries,,, but I say the more amps the better,,,, a diesel fires on warm fuel, compression and revolutions. Interstate's top CCA is rated at 1000 CCA @32*F.... Deka (hard to find, East Penn Mfg) is 1000CCA @ 0*F,,,,,, this is what I use, abuse, and trust...... not a fan of the Optima's either, the early ones where good,,, quality has plumited recently.

Get the MAXX from Wally world and be done. Get 1000 CCA that will fit. At least 900 if pinced for room. Easiest warranty if go bad. 3 years free replace. good to go.