Cutting into the Floorpan

I’ve thought about adding a battery in the back of the Sprinter. I’m thinking I can tap into the wiring for the rear AC. Put a breaker and isolator in the AC shroud. Run a 4 gauge wire down to a switch and then to the floor where I would mount a battery.

This got me thinking, why not cut through the floor. I could weld up a battery box and drop it in the ‘hole’ and then use a floor hatch to access it. This would keep the battery out of the cargo area and out of the weather. Looking under the van there is tons of space on the outside of the rails on both sides (although the pass side has the tail pipe to deal with).

I know that RoadTek drops their whole floor (major engineering work) as does Rincon Wheelchair lifts (again major engineering). I wonder has anyone on this forum done the same or similar? I searched and didn’t find anything. It seems like a lot of wasted space under there…

Alternatively does someone make a battery box I could bolt to the frame underneath?

i like your idea, why not?

Many years ago (2006?) there was a thread showing a hinged drop-down angle-iron frame (not box... the batteries were exposed to the elements).

I was trying to find an old copy of MB's "Body Builders Reference" manual.... if/when i do, i'll post it (or a link to it).
Here is the 2002 version (newer ones have more stuff, but it's a start): View attachment Sprinter2002Body Builders Handbook.pdf

If your van does not have the cargo area secondary heater (a second heater core plumbed into the engine coolant), then the area just aft of the fuel fill (B-pillar) is where MB puts that rig (it's where the left-side step well would be if you had a driver-side sliding door)
That said, batteries are a lot heavier than a heater core, so you'd be (further) skewing the driver-side bias of curb weight.

--dick

Remember battery fumes are dangerous if you're running a non-sealed battery but i've had sealed ones that leaked too. Better safe then sorry, vent it to the outside

Pilot-PJ said:

I’ve thought about adding a battery in the back of the Sprinter. I’m thinking I can tap into the wiring for the rear AC. Put a breaker and isolator in the AC shroud. Run a 4 gauge wire down to a switch and then to the floor where I would mount a battery.

Click to expand...

Just what exactly are you hoping to achieve with doing this?
Where does the battery get charged from?
What are you going to power from it?

The expo van people do this all the time. Especially the ones who relocate the spare tire. Battery venting issues aren't really a problem unless your charging system is over doing things or you have a really big draw on the load side.

They do produce hydrogen gas, I wouldn't risk it

My LTV has a battery box mounted beneath the aft left floor. Access is a metal cover screwed to the floor, and venting is outside. There is a hold-down clamp incorporated into the box. The spare tire is relocated to a bumper mount.

tinman said:

My LTV has a battery box mounted beneath the aft left floor. Access is a metal cover screwed to the floor, and venting is outside. There is a hold-down clamp incorporated into the box. The spare tire is relocated to a bumper mount.

Click to expand...

That is what I'm thinking but with my long chassis putting it to the side.

Could you take a picture or two of your setup?

Thirty years ago I owned a 1948 White motor company Bus which had the battery box mounted below the floor with a hatch in the floor just as you described. I wanted larger batteries so I welded up a larger box with a side access so that I could maintain the batteries without opening the floor hatch. It worked well for me. I used the vacated original battery to hold a 12 volt motor driven refrigeration compressor for the refrigerator I fabricated.