Installation
Sizing a transformer for a Luna Nova run
Need to pick the right Solaris transformer for a new install, or diagnose whether an existing transformer is undersized.
Size the transformer to 80 % of nameplate, account for voltage drop, and pick the tap that lands the far fixture at 11.5 V or above. Worked examples for Solaris 150 / 300 / 600.
Tools you will need
- Voltage-drop calculator
- Site plan with fixture count + run lengths
Steps
- 1
Add up the connected load
Sum the wattage of every fixture and lamp on the run. For housing-only fixtures (MR16/G4), use the rated wattage of the lamp you plan to install — not the housing's max wattage.
- 2
Apply the 80 % rule
Pick a transformer with nameplate output at least 1.25× the connected load. A 240 W load needs the Solaris 300, not the Solaris 150 at maximum. This buffer keeps the transformer cool and gives you headroom to add fixtures later.
- 3
Plan the runs and the wire gauge
Group fixtures into runs of similar wattage and similar distance from the transformer. Hub wiring (separate run per zone) outperforms daisy-chain because voltage drop resets at the hub. Use 12 AWG for runs under 100 ft, 10 AWG for longer.
- 4
Pick the tap by far-fixture voltage
For each run, calculate the voltage at the farthest fixture. Aim for 11.5–12 V at that fixture. If the calc shows < 11.5 V, move to the 13 V or 14 V tap until the far fixture lands in range.
- 5
Validate at night-walk
Energize the system and measure voltage at the first and last fixture of every run. If you're within 0.5 V of each other and both above 11.5 V, you're done. If not, return to step 4 and re-tap.