How To Connect Solar Panels To A Battery Bank Charge Controller & Inverter

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Solar panels are a great way to reduce your energy costs or to power your off-grid home. More than likely, you also have plans to install a battery bank for cloudy days, power outages or continuous power even when the sun goes down. After all, there is nothing more frustrating than losing power to major appliances like your washer and dryer, or worse still your freezer and refrigerator. 

You can pay a professional to install your battery bank and inverter, but there’s really no need if you are competent with hand tools and can follow directions. To that end, we’ve created this handy step-by-step guide to connecting your solar panels to both a battery bank and the required charge controller and power inverter. You will need all three to run your home’s new backup electrical supply. Let’s get started!

Materials (What You Will Need)

  • Solar panels
  • 1 battery charger
  • 1 power inverter
  • Mechanical lugs
  • 2 AWG cable

ECO-WORTHY 12 Volt 10 Watt Solar Car Battery Charger & Maintainer, Solar Panel Trickle Charger, Portable Power Backup Kit with Alligator Clip Adapter for Car, Boat, Automotive, Motorcycle, RV

300W Power Inverter DC 12V to 110V AC Car Charger Converter with 4.8A Dual USB Ports (Blue)

Gardner Bender GSLU-125 Copper Mechanical Lug, 1/0-6 AWG (2 pk)

Schumacher SC1281 100 Amp 30 Amp 6V/12V Fully Automatic Smart Battery Charger 100A Engine Starter and 30A Boost Maintainer and Auto Desulfator Advanced Diagnostic Testing

InstallGear 12 Gauge AWG 100ft Speaker Wire 99.9% Oxygen-Free Copper True Spec and Soft Touch Cable - Brown

Tools

  • Screwdriver
  • Cable cutters
  • Drill
  • Red electrical tape
  • Crescent wrench

Klein Tools 32500 Multi-Bit Screwdriver / Nut Driver 11-in-1 Multi Tool, 8 Industrial Strength Bits, 3 Nut Driver Sizes, Cushion Grip Handle

Klein Tools 63050 Cable Cutters, Heavy Duty High Leverage Cutters for Aluminum, Copper, Communications Cable

DEWALT 20V Max Cordless Drill Combo Kit, 2-Tool (DCK240C2)

Scotch Vinyl Color Coding Electrical Tape 35, 3/4 in x 66 ft, Red

Crescent 3 Pc. Adjustable Cushion Grip Wrench Set 6", 8" & 10" - AC26810CV

Step by Step: How To Connect Solar Panel To A Battery Bank And Inverter

Step 1: Prepare the Batteries

You will begin by charging up your batteries using an AC battery charger. All batteries need to be at full capacity before you load them into your battery bank container. Make sure you line up all the positive terminals on the same side as you load them in, too. It will make wiring them safer and easier later on.

Step 2: Create the Jumpers

Measure the distance between each terminal so you can cut jumpers from your roll of 2 AWG electrical cable. A jumper is just a short length of cable that runs from terminal to terminal. Usually terminals are wired in parallel to preserve the voltage of the solar panels (wiring batteries in parallel pairs); however, you can always wire them in series, provided the output voltage is the same as the battery bank’s overall output. 

Wiring in series means that your jumpers run from negative terminal to positive terminal in a continuous circuit before connecting leads to the inverter. It’s mostly a matter of preference, but wiring in parallel is considered safer by professional electricians.

Step 3: Prepare the Lid

Punch holds in the battery bank’s lid (NOT the batteries themselves) and run your positive and negative cable leads from the end battery terminals through the lid. You should have a positive and negative lead. It’s best to use red and black wrapped cables for this so you don’t mix up the positive and negative leads when connecting them to the rest of your battery backup system. Some install the charge controller on the underside of the lid, but that’s a matter of preference. 

Step 4: Connect Charge Controller and Inverter to Battery Cables

Check the inverter and charge controller to ensure the controller isn’t connected to the solar panels and that the inverter is switched off. Connect your adapter kit to the solar panel (if you have/need one) first. Next, wire the positive and negative leads from the solar panel to the charge controller. Finally, connect the positive and negative leads from the controller to the inverter.

Also Read: Types Of Inverter

Step 5: Connect Battery Bank to Inverter

You are now ready to wire the inverter to the leads from the battery terminals. Once you’ve done this, all that remains is to connect the inverter to the house current on a switch so you can turn on the battery bank when the primary electrical power is out. If you are running exclusively on solar power, you only need to wire the inverter to the house current and close the lid of your battery bank.

Frequently Asked Questions 

Can I connect the inverter to the solar charge controller?

Yes, you can and should connect your inverter to the solar charge controller. It is a critical step in the safer operation of your solar power backup battery bank.

Can you connect a solar panel directly to a battery?

No, connecting your solar panel directly to a battery is dangerous and creates a significant safety risk. Solar panels experience variations in voltage depending on the level of sunlight during the day, and these changes in voltage can lead to surges that will damage or destroy any batteries you connect. Your battery bank can even explode if you wire directly to the solar panel, damaging both the expensive solar panel and the batteries. 

Is it better to connect solar panels in series or parallel?

Wiring in series or parallel is largely a matter of preference depending on how much voltage output you need, but parallel wiring is considered safer and more stable by most electricians. 

Also Read: The Difference Between Batteries in Series vs Parallel

Conclusion

As you can see, installing your own backup battery bank with a charge controller and power inverter is a simple matter of following directions carefully. With a little effort, some hand and power tools, you can quickly and easily install a backup power system for your solar powered home. You can also replicate the process in your off-grid home or RV to supplement your generator or solar panels. Get started today, and eliminate your dependence on the power grid once and for all.

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