First off are they necessary since they don't completely surround the battery on all sides?

Second, I picked up an H7 battery and the truck turned out to have a H6. The insulation that was on the H6 does not fit the H7. Is there a different insulation that larger and fits the H7 battery?

 

It's not really needed. Yes, there is a larger insulation part available. There are f150s that come with an H7 from the factory. Or you can just make a piece yourself with some insulation you buy on a roll at Home Depot, and some duct tape.

 

I was actually looking at the Design Engineering 010480 kit, but since I need to go to HD or Lowes I'll take a look at what they have.

 

Yeah, I think I have part of a roll of silver poly insulation that cost 10-15 bucks. That and some good quality duct tape will save you a lot of money.

 

When I replaced the OEM battery with a little larger after-market battery, I had to cut the insulation blanket to get it to wrap around. It was about 1-1/2" short. So after I cut and measured, I got out a roll of pipe-wrap tape, and made a "bridge" of sorts to fill the gap. I put the taped part on the outside of the battery (away from the engine. It's been that way for over a year now, and seems to work just fine. Since the black tape is almost the same color as the insulation blanket, it looks perfectly normal (as if that makes a difference anyway). It might be 25 cents worth of tape, plus $150 of my labor of course.

 

Interstate H6 AGM works fine

 

your a little late to the party cause I delt with this almost a year ago