A solar panel lying flat can lose a meaningful share of its output compared with one tilted toward the sun, and adjustable tilt mount brackets are the simplest fix: aluminum legs that bolt to the panel frame and lock at the angle you choose, typically anywhere from 0 to 90 degrees. The common rule of thumb among solar installers is to tilt a fixed panel at about your latitude, steeper in winter and flatter in summer. I mounted a PFCTART 28-inch tilt kit on my STAR 100W panel for RV and off-grid use, and this guide walks through installation and how to pick the right angle wherever you are.
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Kit details come from the PFCTART listing and my own install, covered in full in my adjustable solar panel mounting brackets review. You can find the PFCTART 28-inch tilt mount kit on Amazon. Output gains and angles below are estimates and rules of thumb.
What a tilt mount kit includes
Most adjustable kits follow the same design: rails that bolt to the panel frame and folding legs with a row of holes or a slot to set the angle. Per set, the PFCTART kit I used includes:
| Part | Qty per set | Purpose |
|---|---|---|
| Aluminum mounting rails | 4 | Attach to panel and to the surface |
| Aluminum tilt angle brackets | 2 | Set and hold the angle (0–90°) |
| Steel bolts + wing nuts | 6 + 6 | Tool-free angle changes |
| Hex head bolts, flange nuts, lock washers, washers | 4 each | Attach rails to panel frame |
| Self-tapping screws + plastic retaining rings | 6 + 6 | Fix to roof, wall or deck |
The listed size is about 28.46 inches, which suits 100W-class panels like my STAR 100W (about 38.2 × 22.7 inches). For larger panels, check the rail length and the panel’s mounting hole spacing first.
Tools you’ll need
- Wrench or socket set for the frame bolts
- Drill and bits if fixing to a roof, deck or wall
- Tape measure and a phone angle app or inclinometer
- Sealant (for roof mounts) and a compass app to find true south
Step-by-step installation
- Lay the panel face down on a blanket or cardboard so the glass doesn’t scratch.
- Line up the rails with the pre-drilled holes on the panel frame. Many panels, including my STAR 100W, have holes along the long sides.
- Bolt the rails to the frame with the hex bolts, washers, lock washers and flange nuts. Snug, then tighten evenly so the frame isn’t stressed.
- Attach the tilt brackets between the upper rail and the base rail on each side.
- Set the angle by choosing a hole position and locking it with the bolts and wing nuts.
- Fix the base rails to the ground, deck, roof or wall with self-tapping screws, or weigh them down for portable use.
- Connect the MC4 leads to your charge controller or power station and confirm the input watts rise as you fine-tune the angle.
For portable setups, I leave the base unscrewed and use sandbags or a couple of bricks on the rails. On an RV roof, use the manufacturer’s sealant over every screw.
How to choose the tilt angle
The latitude rule of thumb
For a panel that stays at one angle all year, set the tilt about equal to your latitude. To favor a season, adjust by about 15 degrees:
| City (approx. latitude) | Year-round | Winter (lat + 15°) | Summer (lat − 15°) |
|---|---|---|---|
| Miami (26°N) | ~26° | ~41° | ~11° |
| Los Angeles (34°N) | ~34° | ~49° | ~19° |
| Denver (40°N) | ~40° | ~55° | ~25° |
| Seattle (47°N) | ~47° | ~62° | ~32° |
| San Juan, PR (18°N) | ~18° | ~33° | ~3–5° (keep a slight tilt to shed rain) |
Tilt is measured from horizontal: 0° is flat, 90° is vertical. Point the panel toward true south in the Northern Hemisphere.
The quick field method
On a portable setup, the fastest way is to watch your power station or charge controller. Start at the table angle, then tilt a few degrees each way and keep the angle with the highest input watts. Around midday, a panel pointed straight at the sun casts the smallest shadow behind it.
How much does tilting help?
Gains depend on season, latitude and how often you adjust. As a rough guide:
| Setup | Relative daily output (estimate) |
|---|---|
| Flat on the ground (0°), winter at 34°N | Baseline |
| Tilted to latitude, facing south | Noticeably higher, especially in winter |
| Adjusted seasonally (4 times a year) | A few percent more than fixed-at-latitude |
| Manually re-aimed through the day (portable) | Highest of these options |
Worked example (estimate): if a flat 100W panel gives 350Wh on a winter day, a 15–30% boost from tilting would mean roughly 400–455Wh, enough for an extra few hours of a Starlink Mini. For how panel specs affect output, see my guide to Voc, Vmp and temperature coefficients.
Mounting surfaces compared
| Surface | Pros | Watch out for |
|---|---|---|
| Ground | Easy to adjust and clean | Shade, pets, theft |
| RV roof | Always ready, out of the way | Wind load while driving; lower to flat before travel |
| Wall or balcony | Great for steep winter angles | Fixed orientation |
| Flat roof/deck | Plenty of room for rows | Row spacing to avoid self-shading |
Wind and safety tips
- Lower the panel before driving. A raised panel on an RV roof acts like a sail.
- Ballast portable stands. Steeper angles catch more wind.
- Check bolts every few months. Vibration and temperature swings loosen hardware.
- Keep a slight tilt even in summer so rain and dust run off.
Spacing rows so panels don’t shade each other
If you set up more than one tilted panel in a row, the front panel’s shadow can fall on the one behind it, and even partial shade cuts output sharply. Winter is the hardest case because the sun sits lowest. Here’s how to estimate the gap:
- Find the panel’s raised height. Height = tilted panel length × sin(tilt angle). For a panel tilted along its 22.7-inch side at 49°, that’s 22.7 × 0.75 ≈ 17 inches.
- Find the winter noon sun angle. A common approximation is 90° − latitude − 23.4°. In Los Angeles (34°N), that’s about 32.6°.
- Divide height by the tangent of the sun angle. 17 ÷ tan(32.6°) ≈ 17 ÷ 0.64 ≈ 27 inches of gap behind the panel (estimate).
| Location | Winter tilt | Raised height (22.7 in side) | Gap behind panel at winter noon (est.) |
|---|---|---|---|
| Miami (26°N) | ~41° | ~15 in | ~17 in |
| Los Angeles (34°N) | ~49° | ~17 in | ~27 in |
| Denver (40°N) | ~55° | ~19 in | ~38 in |
| Seattle (47°N) | ~62° | ~20 in | ~55 in |
Morning and afternoon shadows are longer than the noon figure, so add some margin if you want full output for more of the day. If you’re short on space, a slightly flatter tilt lets you put rows closer together, at the cost of a little winter output.
A five-minute portable setup
For camping, I keep the brackets bolted to the panel and only change the angle at the wing nuts. My routine:
- Use a compass app to face the panel south (true south, not magnetic).
- Set the angle from the latitude table, then fine-tune while watching input watts.
- Put a sandbag or a couple of rocks on the base rails.
- Re-aim once or twice during the day if I’m around. Moving the panel to follow the sun from east to west matters more than the exact tilt.
The first time I did this with the STAR 100W, the setup took longer than five minutes because I was still learning the hole positions. After that, it became quick. Marking your common winter and summer holes with a paint pen speeds things up.
Picking the right kit size
Tilt kits are sold by rail length. A kit around 28 inches matches a 100W-class panel’s short side. Larger 200W panels and residential panels usually need longer rails or a kit sized for that panel. Measure the panel’s frame and the spacing of its mounting holes, then compare them with the kit’s rail length and slot positions before you order.
FAQ
What’s the best angle for solar panels?
About your latitude for year-round use, roughly 15° steeper in winter and 15° flatter in summer.
Do tilt brackets fit any panel?
Most kits fit framed panels with mounting holes. Check rail length and hole spacing against your panel’s dimensions.
Can I use tilt mounts on an RV roof?
Yes, but fold the panels flat before driving and seal every roof screw.
How often should I adjust the angle?
Seasonally is a good balance. Portable users can re-aim during the day for extra output.
Does a tilt mount help with cleaning?
Yes. A tilted panel sheds rain and dust more easily than a flat one.
Do tilt brackets work with flexible panels?
Not directly. Flexible panels don’t have a rigid frame with bolt holes. You’d need to mount them to a rigid backing board first, and many people simply lay them on a curved surface instead.
Should panels face south or east-west?
In the Northern Hemisphere, a single fixed panel gets the most daily energy facing true south. East-west layouts spread output across the morning and evening, which some people prefer, but they produce less in total.
Bottom line
Tilt mount brackets are a cheap, simple upgrade that gets more from every panel. Bolt the rails to the frame, set the angle near your latitude, face true south and adjust with the seasons. For portable and RV setups, a quick check of input watts is the best way to find the sweet spot.