Hey everyone! So, I've set up a DIY solar system with an 11.5kW solar panel setup and an inverter, along with 48v 280AH LiFePO4 batteries. Right now, it works great for powering my critical loads at night and charging via solar during the day. However, I want to know if there's a charger I can plug into the grid that would let me power loads from the batteries while also charging them at the same time. My local electric company wants me to complete an interconnect agreement, which seems complicated and pricey, so I'm looking for a simple way to keep the batteries charged overnight without worrying about the grid. Is there such a device that can handle this? Thanks for your help!
3 Answers
You might want to check out some products from Eg4 or Eco Worthy; they sell what's called a "chargeverter". It’s designed to charge 48v batteries and works on both 120 and 240 volts. There's telecom equipment that does something similar too. You can usually find used ones for around $200 on eBay. If you set it up with a timer and plug it directly into your outlet, you could keep charging the batteries without complicating your system. It won't be super efficient, but it should work for your needs.
What you're looking for sounds like an all-in-one off-grid inverter charger, like the one linked [here](https://signaturesolar.com/eg4-3kw-off-grid-inverter-3000ehv-48-3000w). This could simplify things. However, if you're specifically trying not to connect back to the grid, I suggest looking for something that can plug directly into your batteries. If you're only dealing with one battery, it’s pretty common to have the charger supply power while charging. Just note, it may slow your charging process.
Pretty much any charger can handle powering a load while also charging batteries, as long as the charger is current limited. The load will simply take from the battery's power, meaning the batteries will charge more slowly. This setup is common in telecommunication and substations that use different voltages, but the principle remains the same. Just keep in mind that for larger battery stacks and more complex systems, things can get pretty tricky with overcharging and managing battery health.