Thinking of mounting my batteries under the back of the rig to keep the weight low and towards the back, but if they were to get submerged in a water crossing, does the water cause them to short out instantly, or would they be ok?

they would be perfectly fine, i would use a seal battery like an orbital or the like so no water can mix with the electrolyte.

they would be perfectly fine, i would use a seal battery like an orbital or the like so no water can mix with the electrolyte.

Yes, both are optimas

So long as you're not trying salt water crossings you'll be fine. If you are, i don't think it owuld instantly short but it would definitely up the discharge rate and encourage corrosion.

Justin

Back of the truck is fine but you'll have a voltage drop, a battery is under the hood and close to the starter for a reason. If you want the weight at the back look into a bigger cable for the positve to the front and ground the battery at the rear frame, as long as the ground strap from engine to frame is still connected. If not you'll be chasing alot of electrical problems.

i never had an issue, i sunk my 78 f150 back when it was stock (water was over the hood) and it took us 3 hours for my buddie to show up to pull me out, after he pulled me out my truck fired up with no hesitation and the battery was under water all that time

I have had atv batteries underwater/mud for hours at a time with no issues other than a mud covered battery.

I just took a class at work (fire dept) about the hybrid cars and water hazards. It will discharge the battery if left in the water for a period of time. Like if you stall out in the water. I would get it out as quick as possible so you you still have enough juice to start it. And if you have a hybrid car and drive in the water..... you are screwwed........ some cars will kill anything in about a 50ft radius.