Loads
Can I run a borehole pump on solar in South Africa?
Yes, with a proper load study. Many domestic boreholes use 0.75–2.2 kW motors with high start surge. Daytime pumping into a JoJo under PV is the clean tariff win (avoiding 320–470 c-class imports). Running the same pump from a lean Stage battery without surge headroom is how hybrids fault. Soft-starters, VSDs, pressure bands and “pump off essentials” are the usual design answers — not a bigger brochure battery alone.
Updated 27 October 2026 · Illustrative ranges — not a formal quote or legal advice.
Tariff maths before the motor sticker
A 1.5 kW borehole that runs two hours uses 3 kWh. At ~400 c retail that is ~R12 per cycle; six cycles a week is ~R72/week if grid-imported. Move pumping into sun hours and you attack that line directly. Exporting the same 3 kWh at ~150 c credit is only ~R4.50 — another self-use > export story. Fixed municipal charges still print either way — metro tariffs · self-consume vs export.
Surge, not only running watts
Direct-on-line single-phase motors can demand several times running current at start. A hybrid that “has 5 kW continuous” may still trip on LRA when the fridge compressor coincides. Ask the borehole contractor for motor kW, start method and measured amps. Soft-starters and VSDs cut the punch; pressure switches with wide bands stop short-cycling. Three-phase supplies change the conversation — phase guide · inverter sizing.
Day tank / JoJo strategy
Pumping to storage under PV, then gravity-feeding or using a small pressure pump, decouples household water from Stage slots. Farms and peri-urban plots that already live on tanks should put solar-aligned refill on the brief before upsizing lithium for “borehole through Stage 4.” Livestock and irrigation schedules need honest seasonal hours — farm solar.
Backup-board policy
Default for lean urban essentials boards: borehole off backup. Exceptions: medical water needs, livestock, or large hybrids with documented surge budget and usable kWh. Never discover the borehole contactor on essentials during the first long slot when the ONT dies mid-pump — essentials · backup sizing · runtime.
Generator hybrids and changeovers
Some smallholdings keep a generator for deep multi-day autonomy. Changeover/ATS design, earthing and CoC rules still apply — amateur neutrals kill equipment. If the generator is only for the borehole starter, ask whether a VSD + daytime PV tank fill retires that diesel habit — changeover / ATS · generator vs hybrid.
Worked sketch
Plot uses 4 m³/day; pump delivers 2 m³/h at 1.5 kW → 3 h × 1.5 kW = 4.5 kWh/day. Sun-aligned refill under a 6 kWp hybrid with tank storage avoids ~R54/day at 400 c on heavy weeks. Sizing the battery to run the same pump for a 4-hour Stage without a tank can demand large surge headroom and kWh for little monthly rand — usually the wrong order.
Owner checklist
- Motor kW, start method and measured amps on the brief.
- Day tank / pressure strategy decided before battery upsize.
- Pump circuit marked on or off essentials in the single-line.
- Coincidence loads (geyser, pool) staggered in sun hours.
- CoC / changeover documented if generator remains.
Single-phase vs three-phase boreholes
Many suburban plots run single-phase 0.75–1.5 kW pumps; smallholdings often step to three-phase 2.2 kW+. Three-phase hybrids distribute surge better but cost more and need matching supply. Do not quote a single-phase 5 kW hybrid against a three-phase borehole without an electrician’s phase plan — phase guide.
Cable length, head (metres) and pipe friction change real watts. A pump labelled 1.1 kW on a deep Highveld borehole with long delivery can draw differently from a shallow coastal well. Demand a pump curve and recent amp reading, not only the rusted nameplate.
Water security vs bill cut — rank them
- Tank storage sized for your longest realistic outage + dry-spell buffer.
- Sun-aligned refill with VSD/soft-start.
- Hybrid surge rating checked against measured start.
- Only then battery kWh for pump-on-backup (if ever).
Farms mixing irrigation timers with domestic tanks should separate circuits so a pivot cannot sink the house essentials board — farm solar · commercial.
Owner field test
- Clamp meter on start and run.
- Fill times for each tank logged on a sunny Saturday under PV-only.
- Stage simulation with pump locked out — confirm house essentials survive.
- One-page SOP for farm staff: when not to override the timer.
Docs: read a quote · earthing · SPD.
JoJo sizing sketch and dirty-power footnotes
If the house uses 1 m³/day and you want two Stage-free days of buffer, start around a 2–2.5 m³ tank before fancy electronics. Livestock and irrigation multiply that fast. Float switches that chatter create pump short-cycles — wide hysteresis saves both the motor and the hybrid. SPDs and correct earthing on long rural runs are not optional theatre when lightning walks the Highveld — SPD · earthing.
Generator + hybrid sites need a documented changeover so the borehole starter cannot backfeed. Label dual supply. File the CoC with the pump VSD settings printed — the next technician will thank you — ATS · CoC.
Bill reminder: every sun-aligned m³ avoids retail kWh. At 400 c, 4.5 kWh/day of pumping is ~R1 800/month if it had been grid-imported on heavy weeks — worth more than chasing export credits at ~150 c. Rank self-use, then storage, then Stage pump rights.
Seasonal yield and livestock peaks
December irrigation and August frost protection change pump hours. Size PV and tanks for the season that actually stresses you, not the average brochure month. Livestock water peaks can force a generator fallback even with a handsome hybrid — write that fallback before the first dry heatwave. Keep a mechanical bypass so a failed VSD does not strand animals. Revisit amp readings yearly as bearings wear and heads change.
Self-use still leads the rand story: sun-aligned pumping against 320–470 c-class imports beats thin export credits every week you remember to leave the timer alone.
Print the owner checklist, paste your real tariff cents beside it, and refuse any quote that cannot show the same arithmetic with your bill as the input. Solar News 24 pages are education — confirm every figure on the live municipal or Eskom PDF and on the installer datasheet before you pay a deposit. When in doubt, prioritise daytime self-use against retail rates, then Stage essentials hours, then export credits.
- Tariff name and date on the brief.
- Flexible loads listed with sun-hour plans.
- Essentials board drawn with watts.
- Usable battery kWh and hybrid backup kW stated.
- SSEG / CoC / meter responsibilities named.
- Portal access and a loaded test before final payment.
Soft-start and hybrid continuous kW
Motor start current can trip undersized hybrids even when steady-state watts look fine. Ask for soft-start / VSD options and whether the pump sits on essentials. Tank storage often beats trying to pump during Stage — farm solar · inverter size · essentials.
Start surge is the silent killer
A pump that draws 1.5 kW running can surge several times that at start. Soft-start, pressure switches and dedicated contactors matter more than a brochure “borehole ready” badge — overload lessons · inverter size · essentials.
Daytime fill vs Stage backup
Fill JoJo tanks on PV surplus; keep the pressure pump off the essentials board unless life-safety needs water during Stage. Related: export vs self-use · Stage strategy · farm solar.
Quote lines
- Nameplate + measured start amps.
- Soft-start / VFD option priced Incl. VAT.
- Which board feeds the pump.
- Whether the hybrid can auto-shed it on Stage.
Desk checklist before you put a borehole on solar
Re-open the live metro tariff PDF, the OEM warranty sheet and your last twelve months of kWh before you compare Incl. VAT totals. Screenshot export-limit and SoC settings at handover so the next technician inherits facts, not folklore — read a quote · fixed charges · 2026/27 tariffs · metro tariffs hub · monitoring · SSEG · red flags.
Quick questions
Will solar run my borehole during load shedding?
Only if the pump is on a backed-up circuit and the hybrid was sized for running watts plus start surge. Most lean Stage boards leave boreholes off.
Is a VSD worth it?
Often yes for surge control and softer starts on hybrid backups; ask the pump tech and electrician together, not in separate WhatsApp threads.