Installed a deep cycle auxiliary battery

[Goran]

I hell freight so I sleep in my van most days. Decided to install a second battery (without isolator because I'm not going to be running fridges and showers, plus I drive at least 300 Miles daily so the batteries won't get a chance to get drained) and insulate the back. The next project is installing the diesel heater in the back. Anyway also have a question what's the best way to connect the inverter to the batteries? I downloaded the MB outfitters manual and the power tap under the drivers seat is only 40 amps. Should I just hook up the inverter straight to the second battery? The picture isn't the finished product. I'm storing it under the pasager seat. For the insulation I went with reflectix as a vapor barrier ,I didn't need one but I needed up and bought a bunch of it because I thought I could insulate just with that, and 2 different kind of foam board insulation. The pink stuff from home Depot and the styrofoam with a reflective side from Lowe's. They're both great. Don't know what to use for the floor because I can't lose space hauling freight plus I need to put my original floor in top because I have the tiedown rings in there.

 

[Kevin.Hutch]

I hall freight so I sleep in my van most days. Decided to install a second battery (without isolator because I'm not going to be running fridges and showers, plus I drive at least 300 Miles daily so the batteries won't get a chance to get drained) and insulate the back. The next project is installing the diesel heater in the back. Anyway also have a question what's the best way to connect the inverter to the batteries? I downloaded the MB outfitters manual and the power tap under the drivers seat is only 40 amps. Should I just hook up the inverter straight to the second battery? The picture isn't the finished product. I'm storing it under the passenger seat. For the insulation I went with reflectix as a vapor barrier ,I didn't need one but I needed up and bought a bunch of it because I thought I could insulate just with that, and 2 different kind of foam board insulation. The pink stuff from home Depot and the styrofoam with a reflective side from Lowe's. They're both great. Don't know what to use for the floor because I can't lose space hauling freight plus I need to put my original floor in top because I have the tiedown rings in there.

A re-post in the "Sprinter RV's & Conversions Talk" would achieve more comprehensive results. My suggestion is post one question per post so the answers do not get confused and the topic will solicit those interested in the topic.

The tap under the seat is recommended for maximum 40amp but it is fed by a 150amp fuse on the start battery and what should be a 35sqmm (just over 2 AWG) cable, although it may have a 90amp, ignition operated relay, you need to provide the 40amp control.

 

[192019]

You should really consider installing a DC-DC Converter (Buck/Boost) system, like the one from Victron. If you read the MB upfitter guide, you would see why the converter is required. Especially if you run an inverter. Personally, you should have two AGM in series or one decent sized Lithium. the Victron has options for charging Lithium batteries, as the charging cycle is unique and temperature dependent.
It will charge the house batteries as you drive, and you can alter the output amperage for the type of battery you have installed. I would not think you would want to use the chassis battery as part of the inverter supply.
It is a small unit, and will fit under the driver's seat. Google Victron Buck Boost.