48 Volt System for Ambulance RV Conversion

[AmboMan]

Hi Everyone,

This is my first post in the forums and I am looking to get opinions on the next off-grid system I build.

I am converting an ambulance into an RV and am able to start completely from scratch. I want to make this a completely electric build with the exception of using a diesel heater for heating the place. I would like to be able to run this completely off solar with a back-up generator in the case that I may need it.

Here are the larger loads

- 9,000 btu Inverter AC unit (R10 insulation walls and ceiling / R5 floors)
- 1,800 watt induction cooktop
- 1,800 watt microwave oven
- 1,500 watt hot water heater (15 minutes to heat)

I would like to run 200 amp hours (possibly 300) of the 48 volt EG4 Batteries along with the EG4 6500EX all in one unit. I will be able to fit 1800 watts of solar on my roof with the possibility of another 900 if I do a sliding rack design. I love the fact that I can also rapidly charge my batteries with shore/generator power.

If I do this I would leave it on 24/7 and I would want to run nearly everything on 120v power including my fridge, lights and fans. One thing I really want to do is leave my Starlink internet on 24/7 as I want to use some smart home devices and security cameras. I will still have some small 12 volt loads that I will use a DC to DC converter for.

My main concerns are around the high idle consumption rate of this unit (70 watts) and the overall efficiency of inverting 48vdc to 120vac. My biggest draw will be my air conditioning unit but even then I hope good insulation and a high seer rated inverter mini split will lower my consumption.

I want to hear your thoughts and opinions on this setup and if there is a better/cheaper way to achieve what I am looking for.

Thanks!

 

[MrThisIsME]

Lots to discuss here, but the one thing you did not call out is your fridge consumption. A standard RV 2-way (AC and propane) fridge is one of the most inefficient and possibly your largest draw concern if you had one (figure 400watts 85% of the time). Being a conversion you might of used something different???

 

[AmboMan]

Thanks, you are right I did not specify the fridge. I can either run a 12 volt fridge off a DC to DC converter or run a 120 volt residential fridge right off the inverter.