EG4 48v battery & Inverter purchase

[OnGrid]

I'm thinking about making a purchase for a solar system that won't be tied into the grid, but will have grid power available.

Plan to have one or two 48V batteries and a 3000W inverter with 10 280w solar panels, do I need to purchase a battery charger too?

And if so, why would i need it?

 

[robby]

A Battery charger is not really needed if your inverter can charge the batteries from an AC input.
The only other reason you might want one is if you have a generator that cannot be hooked into the Inverter and you want to charge the batteries after a storm that has left you without grid power or panels. Also people us them to recover batteries that have discharge so low that the BMS will no longer engage.
Overall very rare events. I have had one for 18 months now and never used it. YMMV depending on what features your inverter has.

 

[MichaelK]

What you are talking about is typically represented as a "hybrid inverter". There are two broad classes, component inverters, and AllinOne inverters.

The component hybrid systems are assembled from individual components, an inverter, a charge controller, battery bank, and solar input. The highest quality, tier-1 products are typically, but not always components.

The AllinOne systems, or AiO, is an inverter, charge controller, battery charger, all built into one box. Buy the box and you have everything included. AiOs though tend to occupy the lower end of the quality spectrum, but not always.

Typically a hybrid inverter will be powered via a DC battery bank, either 12, 24, or 48V. The inverter then makes 120VAC (or 120/240VAC) that the house uses. ACout terminals somewhere on the inverter lead out to your main electrical panel, to power your loads.

A hybrid will also have ACin terminals to accept power from the grid or a generator. My XW+ has two ACins, one for the grid, and a second for a generator. It has an automatic transfer switch built-in. That is so grid(generator) power and the inverter power can never meet. You hook up a standard inverter to your electrical panel the same way, but you MUST install your own transfer switch.

Before you make a decision on what to buy, you need to slow down a bit and draft up an itemized list of what it is you want to power. A good rule of thumb is to have at least 2X the inverter capacity of your single largest load. To me, 3000W is a bit small for a 48V inverter, so you really need to pin down your power consumption first.