Hey everyone! I'm new to designing my off-grid system and have a question about managing idle loads. I'm planning to use an EG4 3KW inverter along with one or two 48V 100aH batteries. My goal is to keep a composting toilet (Natures Head) running continuously with a small fan that uses about 1.7aH per day. The inverter itself has an idle draw of around 50W. Since my cabin will be empty for about 90% of the time, I'm worried about cycling the batteries just to power the toilet fan and the inverter's idle load. What are some strategies for handling this? Also, since the toilet is about 30ft away from the main building, should I choose AC power (like an extension cord) or a 12V or 48V DC setup? Will wire gauge and power loss be issues in this scenario? Any tips or suggestions would be greatly appreciated! Thanks!
5 Answers
For your composting toilet, brands like Sun-Mar offer fans that can work with either AC or DC power. It's worth checking if Natures Head also has that capability since having that flexibility can really simplify your setup.
One thing you might try is to set your inverter's top voltage to around 51.2V when you're away. This helps maintain the batteries at about 80% charge, which is generally better for their long-term health.
You should consider running the toilet fan on either 12V or 48V directly. This way, you can avoid using the inverter altogether. Since the load is so low and the toilet is 30 feet away, think about setting up a small battery with a tiny MPPT and a solar panel dedicated just to powering the fan separately from your main off-grid system.
Just out of curiosity, is your inverter the EG4 3000EVH model? I had a lot of trouble getting the app to work with mine—super frustrating!