Solar Panel Kits: What's Included and Which Size Fits Your Home

A solar panel kit bundles the parts to turn sunlight into stored power: panels, a charge controller, cables, connectors and mounting brackets. Most starter kits leave out the battery and the inverter. A 100 W kit suits a shed’s lights, a 400 W kit with a battery suits a weekend cabin, and home backup needs a battery-based power kit.

What comes in a solar panel kit

A starter solar panel kit covers everything between the sun and the battery. Renogy describes its 400 W, 12 V starter kit as a panel set, a charge controller, the needed wiring, Y-branch connectors and Z-brackets. The kit pairs four 100 W panels with a 30 A Wanderer PWM controller.

The smallest version follows the same pattern. Renogy’s 100 W, 12 V kit pairs one panel with a 10 A Wanderer PWM controller, wiring and a set of Z-brackets.

What you still need to buy with a solar kit

A solar kit without a battery only works while the sun shines, and most loads run at night. The South Carolina state energy office lists the parts of an off-grid system as panels, a charge controller, batteries that store unused solar energy for night, and an inverter for AC appliances. Its guide adds that a generator or other source can back the system up when the battery runs low.

Plan for three extra purchases:

• A deep-cycle battery matched to the kit’s voltage, usually 12 V for small kits.
• An inverter if anything you run plugs into a wall outlet. Lights and fans built for 12 V can skip it.
• Fuses and a disconnect between the battery and controller, as the controller’s manual specifies.

If wiring a battery bank sounds like more than you want to take on, a power station with a matching portable panel does the same job in one box. Our guide to charging a solar generator shows how panel watts and the station’s solar input limit fit together.

PWM or MPPT controllers in solar kits

Kits in the same size often come with two controller choices. Renogy sells its 400 W starter kit with a 30 A PWM controller or a 40 A MPPT controller, and says MPPT transfers power up to 30% more efficiently than PWM. Check which controller a listing actually ships.

A PWM controller is simpler and suits one or two panels on a small 12 V battery. MPPT earns its place on bigger kits and on panels wired in series.

Sizing a solar panel kit for a shed, cabin or home

Sizing a solar panel kit starts with your loads, not the panels. Add up each device’s watts multiplied by its hours of use per day. That total in watt-hours is what the panels must refill each day and what the battery must hold overnight.

Panel output depends on your local sun. The PVWatts calculator from the National Laboratory of the Rockies (formerly NREL) estimates production for your location. As a worked example only: a 100 W panel that gets the equivalent of 4 hours of full sun makes about 400 Wh before wiring and controller losses, and less in winter.

Home backup is where kits get large. Battery-based power kits combine a large battery bank, an inverter and a set of panels, and the contents vary from bundle to bundle, so read the parts list before you compare prices. To work out how much battery a home outage needs, see what size solar generator you need and solar generators for home backup.

Off-grid kits versus grid-tied home solar kits

An off-grid solar kit charges its own battery and never connects to the utility, which is why sheds and cabins use them. A grid-tied kit feeds your home’s wiring and needs approvals first. The U.S. Department of Energy says home solar is installed to local building, fire and electrical codes and inspected by a certified electrician, and your utility sets the rules for any power you send back to the grid. Ask your building department and your utility before you buy.

A plug-in balcony kit sits between the two. It plugs into an outlet and is allowed without a full interconnection agreement only in states that have passed plug-in solar laws. Our balcony solar guide lists those states and their size caps.

Checks before you buy a solar panel kit

1. Box contents: what is included and what is missing.
2. System voltage: controller and battery match, usually 12 V.
3. Controller rating: amps cover the panels, with room to grow.
4. Local rules: anything wired to your home needs your utility first.

For the parts themselves, see solar charge controllers, the 12V LiFePO4 100Ah battery guide and off-grid solar inverters. More panel guides are in the solar panels section.