Savings
What solar monitoring numbers should SA homeowners watch?
Watch daily/weekly self-use kWh, grid import kWh, battery throughput, and export (if any) against your tariff diary — not only a green “everything OK” icon. A system that looks online can still waste money via wrong CT polarity, grid-charge at peak TOU, or a wallbox emptying the pack. Ten minutes a week on the app beats a nasty bill surprise.
Updated 27 October 2026 · Illustrative ranges — not a formal quote, credit decision or legal advice.
Answer first: Monitoring is bill literacy, not a gadget hobby. If you cannot see whether midday PV became household self-use, battery charge, or curtailed surplus, you cannot judge the quote’s savings promise.
Weekly scoreboard (save these screenshots)
| Metric | Why it matters on an SA bill |
|---|---|
| PV yield (kWh) | Catch soiling, shade, or string faults early vs the commissioning estimate |
| Self-consumption / self-use | This is usually where the rand lives when export credits are modest |
| Grid import (kWh and timing) | Evening peaks and TOU blocks decide whether the battery earned its keep |
| Grid export | Confirm zero-export settings or that credits match the bi-directional statement |
| Battery SoC cycles / throughput | Spot accidental 100% DoD habits that stress warranty |
| Grid-charge kWh | Resilience tool — expensive if it runs every sunny afternoon “just in case” |
Pair the app with prepaid tokens or the municipal PDF. Apps lie in rand terms when fixed charges dominate — fixed charges · prepaid.
Red flags that need an electrician, not a reboot
- Sunny day, near-zero PV, inverter “online.”
- Battery never charges from PV but grid-charges happily (CT / mode fault).
- Export arrows while you are on a zero-export instruction.
- Essentials drop in Stage though SoC shows 40%+ (wiring / priority / trip).
Related diagnostics: fault codes · zero-export · usable kWh.
TOU and Cape Town-style patterns
If you are on residential TOU, screenshot the evening window weekly. A battery that sits full at 16:00 and still imports at peak is mis-modeled — Cape Town TOU · grid-charge desk.
Handover pack should include login ownership
Plant accounts must sit in your email, not only the installer’s. When the company changes hands, you still need the history for warranty and resale — selling with solar · warranty checks.
Build a simple homeowner dashboard habit
Pick one weekday evening and one Sunday morning. In five minutes record: yesterday’s PV kWh, self-use %, grid import kWh, highest evening import window, battery min SoC overnight, and any export. Drop the notes in the same phone album as your token receipts. After four weeks you will see whether the quote’s “R1 xxx/month” story is landing.
If self-use stays low while PV is high, you are curtailing or exporting on weak credits — redirect geyser / pool / EV or plan the next battery module — export vs self-use · zero-export · expand later.
Winter vs summer baselines
Do not panic in July because daily PV fell 30–50% versus December — that is often normal Highveld / Cape seasonality. Panic when winter import spikes and battery throughput collapses while SoC sits full at midday (mode or CT problem), or when one string dies versus the commissioning file — winter production · degradation.
EV and heat-pump noise in the data
A 7.4 kW wallbox session looks like a “bad solar day” if you only watch grid import. Tag EV and heat-pump hours in your notes so you do not blame the array for controllable loads. Ideally the charger schedule prefers solar surplus windows — charge from solar · heat pump payback.
What to send the installer when something is wrong
- Three screenshots: PV/day, battery SoC curve, grid import/export.
- Photo of the inverter fault/event log.
- Whether Stage was active and which circuits stayed up.
- Your tariff code and whether you intended zero-export.
That pack beats “the app feels wrong.” Related: fault codes · choose installer.
Privacy and guest access
Give the installer technician access, not ownership of the primary login. Remove ex-staff accounts when companies change. For Airbnb / guesthouse stacks, keep monitoring on the owner account so guests cannot rewrite modes — Airbnb solar.
Fixed charges will not appear in the inverter app
Remember: municipal fixed / capacity / network-access lines sit on the bill PDF, not in the hybrid portal. A “perfect” self-use week can still disappoint if you migrated onto a steeper fixed charge with SSEG — reconcile both documents monthly — fixed charges · metro tariffs.
Illustrative weekly review script (10 minutes)
- Open yesterday and the last 7 days in the portal.
- Note PV total vs a clear-sky neighbour expectation or your commissioning estimate.
- Check whether evening grid import fell on nights the battery discharged.
- Confirm export is ~0 if you are zero-export instructed.
- Glance at grid-charge kWh — unexplained afternoon grid-charge is a mode bug until proven otherwise.
- Photograph any fault codes; clear only after logging them.
If import barely moved after commissioning, the problem is usually CT placement, tariff assumption, or loads still peaking off-sun — not “panels are fake.” Related: read a quote · AC vs DC CT notes.
Sharing data with a second opinion
When you seek a second installer opinion, export CSV / monthly PDFs rather than WhatsApp screen recordings alone. Clean data shortens arguments about whether the array underproduces or the household simply runs the pool pump at 18:00 — pool pump · monthly savings.
Commissioning baselines worth freezing on day one
- Installer yield estimate (monthly or annual kWh) with weather assumptions named.
- Screenshot of correct CT orientation test (big load on, import arrow correct).
- Essentials circuit list that stayed up in the Stage simulation.
- Min SoC / DoD / grid-charge windows as left on the day of handover.
- Tariff code the savings sheet used — compare to your actual bill header.
Without baselines, “underperforming” is a feeling. With them, it is a ticket the installer can action — choose installer · DoD · check a quote.
If you finance via a bond further advance or energy loan, lenders may also want proof the plant operates — keep the same album tidy — bond / finance.
When good monitoring saves a warranty fight
Capacity fade and sudden step-losses look different on a chart. Weekly SoC and throughput history help the SA claims desk see misuse versus a defective module. Export the log before you reset anything after a fault — claim steps · warranty checks · battery lifespan.
Owner habit: if you only open the app when the lights flicker, you will miss the quiet bill leaks. A recurring Friday reminder beats heroics after a nasty statement — pair it with the token or PDF bill the same day.
Weekly 10-minute audit
- Self-use % vs export kWh — export should be leftovers.
- Battery throughput vs Stage nights — empty at 16:00 is a settings smell.
- Import during sunny midday — timers or phantom loads.
- One underperforming string vs its twin — dirt, shade, or damage.
- Grid-charge kWh on expensive blocks — turn it off unless a Stage calendar justifies it.
Related: grid charge · self-use · bill still high.
Quick questions
Is the inverter LED enough?
No. LEDs do not show tariff timing, CT mistakes or silent curtailment. Use the app / portal weekly.
How long should I keep screenshots?
At least twelve months through a full winter/summer cycle, plus any claim or SSEG query period.
Can monitoring prove a bad quote?
It can show delivery vs promise. Keep the original savings sheet and compare monthly import reduction, not only PV yield.