Batteries/Charge Controller

System

Hi, I'm new to solar. If I want to get a solar grid-tie system, are batteries and a charge controller required or can I make do with just solar panels and an inverter?

From what I can tell all the batteries do is provide a backup system but seeing as how I don't currently have a backup system without solar power I don't see a pressing need to add one as it is more expensive.

The same goes for the charge controller. All it appears to do is ensure that the voltage from the soar panels don't damage the battery bank, but if I don't have a battery bank then I don't need one.

Is this correct or is there some function to the batteries and charge controller that I'm missing?

icarus

Re: Batteries/Charge Controller

For a grid tie, no batteries are required. Adding batteries only increases the cost as well as the maintenance. If you are looking for "emergency" power when the grid is down, a small generator is usually much cheaper. (Unless you grid is REALLY unreliable.

Welcome to the forum, and good luck,

Tony

niel

Re: Batteries/Charge Controller

they aren't required if you have a straight gt inverter, but this ups the required voltage to it and thusly the number of pvs to make that voltage. of course straight gt skips the need of any controllers or batteries, but interfacing to the grid and inspections are still part of the deal.

FL SUN

Re: Batteries/Charge Controller

Just like Tony said, batteries and all that goes with them add more cost and system maint. If you are looking to get a financial payback or return on your solar investment, and you are satisfied with your utility's dependability, batteryless grid-tie is the way to go.

I wanted to do a small battery based solar set-up recently to offset my utility operation cost, but decided against it as it would never pay for itself.

BB.

Re: Batteries/Charge Controller

I too made that decision years ago... Reduced my energy needs such that a small Honda eu2000i (1,600 watt) genset will supply all of my emergency needs. And 20 gallons of stored gas (preservative+rotate once a year into the car/pickup), and a siphon from the family vehicles, will keep me going for several weeks easily.

A whole house genset is pretty cheap... If you have propane--great for fuel storage. Natural Gas, could fail in an Earthquake (my "big one"). Bigger Gensets really consume the fuel (1/2 to several gallons per hour). My choice for conservation and an "tiny" fuel efficient genset reduces a whole bunch of issues (common fuel, fuel storage, easy to move with me, use "spare fuel" in vehicle to cook food or bug out, etc.), and leaves me with more options (on the "cheap").

If after that amount of time, I am still on emergency power (mostly to keep fridge and freezer cold), we have bigger issues.

I treat a power outage like camping. Small multi-fuel stove, emergency tent, sleeping bags (no heat), water storage, and emergency water filters/disinfectant... I can live for weeks without electricity (or even food)--but only a few days without water.

Hybrid Solar (inverter that supports Grid Tied and Off-Grid operation, plus a "smaller" battery bank--not the 6x daily load rule of thumb) is really neat. If you have to live for weeks at a time without power (ice storms, floods, etc.) every year or so--may be worth it for you.

You will probably still want a small genset for bad weather/portable backup anyway.

-Bill