Solar Panels Buying Guide

Ready to invest in solar panels? Our comprehensive buying guide covers everything from types to pricing, ensuring you choose the best option for your home.

Buying Guide

Smart Tips for Choosing Solar Panels

Use this guide to choose solar panels that fit your roof, stay inside inverter limits, and meet your daily kWh target.

Solar Calculator Shop Solar Panels Shop Solar Kits Request a Quote
Focus keyword: solar panels buying guide Roof fit and layout VOC and MPPT checks

Before you buy

  • Your average kWh per day.
  • Your roof type and usable roof space.
  • Shade zones, now and later.
  • Your inverter model, or planned inverter size.
  • Battery use, yes or no.
If you already own an inverter, check MPPT range and max PV voltage first.

Complete your order

Mounting Systems Switchgear and Protection Cables and Connectors Combiner Boxes
Typical build order: panels, mounting, DC protection, cables, then accessories.

Shop solar panel brands

Browse panels by brand, then compare wattage, size, and spec limits.

CNBM Solar JA Solar Jinko Solar Longi Solar Seraphim Solar
Pick a watt range first, then filter by size and stock.

Step 1, set your daily kWh target

  • Use your bill, a meter, or your kWh estimate.
  • Write your average kWh per day.
  • If you use batteries, note night use from 17:00 to 08:00.
A clear kWh target keeps the panel count realistic.

Step 2, estimate array size and panel count

Array size estimate

Array kW = (Daily kWh ÷ Peak Sun Hours) × 1.2
  • The 1.2 factor covers heat, wiring, dirt, and conversion loss.
  • Add margin for winter and cloudy weeks.

Panel count estimate

Panels = Array kW ÷ (Panel watts ÷ 1000)
  • Example: 550W panel = 0.55 kW.
  • Round up, then confirm roof fit and inverter limits.

Step 3, confirm roof space and layout

  • Measure clear roof areas, then mark shade zones.
  • Leave space for walkways, vents, and parapets.
  • North-facing gives strong yearly output in South Africa.
  • East and west spreads output across the day.
Shade on one panel reduces the full string output.

Step 4, check VOC and MPPT limits

Your inverter has PV limits. Your string must stay inside those limits in summer and winter. Cold mornings raise VOC.

Check these inverter specs

  • MPPT voltage range.
  • Max PV open circuit voltage.
  • Max PV input current per MPPT.
  • Number of MPPTs and strings per MPPT.

Check these panel specs

  • VOC and VMP.
  • ISC and IMP.
  • Connector type and cable length.
Keep margin below inverter max PV voltage. Avoid strings built on the limit.

How to compare panels

  • Wattage and size, based on roof fit.
  • Efficiency, when roof space is tight.
  • Warranty terms for product and performance.
  • Cell type, N-type, mono PERC, bifacial.
  • Mechanical strength for wind and hail.
Choose roof fit and inverter limits first. Then compare price per watt.

Common mistakes

  • Buying panels before checking inverter PV limits.
  • Building strings too long and hitting PV over-voltage.
  • Ignoring roof shade and future tree growth.
  • Skipping DC isolators, fuses or breakers, and surge protection.
  • Using the wrong mounts for tile, IBR, or corrugated roofs.

Get a quick sizing check

  • Your city or area.
  • Your roof type and usable roof space.
  • Your target kWh per day.
  • Your inverter model, or planned inverter size.
  • Your backup hours target, if you use batteries.
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Solar panels FAQ

How many solar panels do I need?

Start with your kWh per day target and your location sun hours. Use the Solar Calculator, then confirm roof space and inverter PV limits.

What panel wattage is best for my roof?

Higher watt panels reduce panel count, but each panel is larger. Choose the best fit for roof space and layout first.

What is VOC and why does it matter?

VOC is the panel open circuit voltage. String VOC rises in cold weather. Your string must stay below inverter max PV voltage.

Series vs parallel, what is better?

Series increases voltage, parallel increases current. Most string inverters use series strings inside MPPT voltage limits.

Do I need DC protection for solar panels?

Yes. Use the correct DC isolator, fuses or breakers, and surge protection, based on your system design and voltage.

Do panels work on cloudy days?

Output drops on cloudy days. Plan with margin for winter and bad weather, especially if you rely on batteries at night.

Which roof direction works best in South Africa?

North-facing gives the best yearly output. East-west layouts support morning and afternoon loads and spread production.

What details should I send for a sizing check?

Send your city, roof type, roof space, target kWh per day, inverter model, and whether you use batteries.