New here, Mobile office questions, Need advice

New here, Mobile office questions, Need advice
Hi everyone, I'm new here and joined to get some advice on setting up a mobile office. A little about me, my name is Jim and I'm a catastrophic loss insurance adjuster (property) that is on call and ready to deploy year around. I recently bought a Chrysler Town and Country van that I took the seats out of the back moved the right rear seat behind the passenger seat (facing backwards) and bought a 2/0 x 6/8 hollow core door (resting on the rear armrests) to use as a desk. The whole plan came together nicely and will work great. Now I have the technical stuff to work on. I'll be running a Dell Latitude D630 laptop and a HP Officejet 4500 (5 in 1) and would like to have enough power to run a second monitor (18" - 20") without "pushing" the supply limit too much. So here's some thoughts so far;

Getting an inverter big enough to run the system but I'm wondering if it's necessary to get a pure sine wave inverter instead of the more common modified sine wave models.

Then I thought about plugging a "continuous" UPS to "clean up" the sine wave issue.

Then I thought about eliminating the inverter altogether and tapping into the UPS and running a second battery (gel cell) in parallel with the internal UPS battery. Charging the 12V batteries could be accomplished by running a heavy enough wire from the van battery to the UPS and yes, I would have a switch I could turn on while driving between appointments so as to not drain the van battery so much that I would have a starting problem.

Your thoughts and input would be greatly appreciated,
Jim

I have been on the road for 9 years using many different laptops and printers and running them off modified sine wave inverters without a problem.

You might not need as big of an inverter as you think. You can charge the laptop overnight and then run it in the daytime on batteries. Laptops draw the most power when they are being charged and being used at the same time.

A UPS almost certainly won't work on a modified sine wave inverter, you would need a true sine wave model. A UPS is not intended as a full time power supply but only as a temporary emergency supply in the event of a power outage.  With an inverter, you really don't need a UPS, as that's one of the side benefits of an inverter.  Your biggest power user will be the printer.  Over the course of a day, the computer will use the same amount of power whether you run it on batteries and then charge it or just run it off the inverter.

If you'll have access to 120VAC power when on a site, you may also want to make provision for powering your office from that while parked instead of using your van battery.