Here a few pictures looking from the bottom side. The battery tray is a bit dirty in the pics, but it is painted nicely a glossy black.

 

That's real cool.

 

that is a pretty cool idea, is there any room in the back section of the truck to do it there instead ?
i think some 31D batteries would do a bit of a better job and would also put a band aid on the truck's rear end shimmy from being too light and stiff back there.
i hope i didnt come across wrong with this, just thought about killing 2 birds with one shell.

 

Nice. Gonna make a real mess of things if you ever get in a front end collision. Acid everywhere, but hopefully that will never happen!!

 

I'd worry about a frontal accident as well with the battery up front and personal with the bumper like that too. You could get one of those marine battery boxes to keep the acid in. Just in case you get bounced on the front end. Nice job though. Always good to have enough juice. Especially if your running some big Amps for a sound system, or a winch set up.
Does the isolator have a cut off switch built in it? I'd wanna turn the extra one off if I left for vacation or extended period of time. That way you have some spare if you come back and the truck is dead, like what happened to a few people on here before. Is there enough room in that location for an Optima battery?

 

I too was concerned about battery damage in the event of an accident. This is why I used an Absorbed glass mat (AGM) style battery instead of the standard lead acid wet cell. An AGM battery will not leak acid if the case is split open. AGM batteries can also be mounted in any position.

The spare battery doesn't really need a cut off switch. The isolator prevents the main battery from depleting the spare, and AGM's only lose about 3% charge per month when they are just sitting unused.