Load shedding is the defining constraint for solar in Zimbabwe. Not how much sun you get — that's generous year-round. The question is: when the grid disappears for 4, 8, 12, or 18 hours a day, how much stored energy do you need to keep your house running?
Get this wrong and you're sitting in the dark at 9 PM wondering why your "solar system" died two hours into the evening. Get it right and load shedding becomes background noise — something that happens to other people.
The Stages: What You're Actually Dealing With
Load shedding in Zimbabwe follows a rough staging system. The higher the stage, the more hours per day the grid is off.
| Stage | Hours Off | Typical Windows | What It Feels Like |
|---|---|---|---|
| Stage 2 | 4 hrs/day | 06:00–08:00, 18:00–20:00 | Annoying. Morning and evening gaps. |
| Stage 4 | 8 hrs/day | 05:00–09:00, 17:00–21:00 | Serious. Covers both peak usage windows. |
| Stage 6 | 12 hrs/day | 04:00–10:00, 16:00–22:00 | Half the day without power. |
| Stage 8 | 18 hrs/day | 00:00–06:00, 08:00–14:00, 16:00–22:00 | Grid is a bonus, not a baseline. |
These windows shift. Your area might get different times on different days. The hours-per-day total is what matters for battery sizing — not the exact schedule. Size for the total outage hours, and you're covered regardless of when the cuts land.
The critical pattern: load shedding hits hardest during the hours when you actually use electricity. Morning routines (06:00–09:00) and evening living (17:00–22:00) are exactly when the grid disappears. Solar panels produce power during the middle of the day — but you need it at the edges. That gap is what your battery fills.
What Your Battery Actually Needs to Cover
Your battery doesn't need to power your entire daily consumption. It only needs to cover the hours when both the grid is off and your panels aren't producing.
This breaks into three scenarios:
Daytime outages (panels producing)
If load shedding falls between 09:00 and 15:00, your panels are generating. The battery barely gets touched — solar handles the load directly. This is the easy scenario.
Evening outages (no panels, no grid)
This is the hard one. From sunset (~17:30) until the grid comes back, you're running purely on stored energy. Every watt comes from the battery. Evening is also when you're running the most: lights, TV, cooking, fridge, phone charging, Wi-Fi.
Overnight and early morning
If the grid is off from midnight to 06:00, your fridge, security lights, and router are drawing from the battery. The loads are lighter than evening, but the hours are long.
Sizing the Battery: Stage by Stage
Here's what a typical 4-person Zimbabwe household needs at each stage. We're using real numbers from the SolMate sizing engine: 48V LiFePO4 batteries at 5.12 kWh each, 80% depth of discharge, 95% round-trip efficiency.
The Essential Load Budget
First, establish what you're powering during outages. Not everything — just the loads that matter.
| Appliance | Power Draw | Hours Used During Outage | Energy |
|---|---|---|---|
| LED lights (6 rooms) | 60W | Full outage duration | Varies |
| Fridge/freezer | 100W average | Runs continuously | Varies |
| TV + decoder | 120W | 3–4 evening hours | 0.36–0.48 kWh |
| Wi-Fi router | 15W | Full outage duration | Varies |
| Phone charging (3 phones) | 45W | 2 hours | 0.09 kWh |
| Laptop | 60W | 2 hours | 0.12 kWh |
The always-on loads (fridge, lights, router) draw about 175W combined. Per hour, that's 0.175 kWh. The evening cluster (TV, phones, laptop) adds roughly 0.6 kWh over the evening.
Stage 2: 4 Hours Off
Outage pattern: 06:00–08:00 (morning) + 18:00–20:00 (evening)
The morning block is mostly covered by panels starting to produce from ~07:00. The evening block is the real demand: 2 hours of lights, TV, fridge, and router.
| What | Calculation | Energy |
|---|---|---|
| Evening essentials (2 hrs) | 175W × 2h + evening cluster | ~1.0 kWh |
| Morning gap (1 hr before panels kick in) | 175W × 1h | ~0.2 kWh |
| Total battery draw | ~1.2 kWh |
Battery recommendation: 1 × 5.12 kWh battery (usable: ~3.9 kWh). You'll use about 30% of it. Plenty of headroom.
Inverter: 3 kVA handles this comfortably.
System cost: $800–1,400
At Stage 2, solar is almost overkill. But the system pays for itself in grid savings and scales if load shedding worsens.
Stage 4: 8 Hours Off
Outage pattern: 05:00–09:00 (morning) + 17:00–21:00 (evening)
Now it gets real. The evening block is 4 hours — your entire evening from dusk through dinner and prime time. The morning block starts before sunrise and extends past the time panels begin producing meaningfully.
| What | Calculation | Energy |
|---|---|---|
| Evening essentials (4 hrs) | 175W × 4h + evening cluster | ~1.3 kWh |
| Morning gap (2 hrs before panels help) | 175W × 2h | ~0.35 kWh |
| Microwave (reheating dinner) | 1,200W × 10 min | ~0.2 kWh |
| Total battery draw | ~1.9 kWh |
Battery recommendation: 1 × 5.12 kWh battery (usable: ~3.9 kWh). About 50% utilised. Still comfortable, and the extra capacity covers nights when you use more than average.
Inverter: 3–5 kVA depending on whether you're running a microwave or kettle.
System cost: $1,200–2,000
This is the sweet spot for most Zimbabwe households. Stage 4 is common enough that the system gets daily use, and the payback from displaced grid electricity is meaningful.
Stage 6: 12 Hours Off
Outage pattern: 04:00–10:00 (morning) + 16:00–22:00 (evening)
Half the day without power. The evening block now starts at 4 PM — before sunset — and runs until 10 PM. The morning block starts at 4 AM and runs until 10 AM, eating into your peak solar window.
| What | Calculation | Energy |
|---|---|---|
| Evening essentials (6 hrs) | 175W × 6h + evening cluster | ~1.7 kWh |
| Morning (3 hrs before meaningful solar) | 175W × 3h | ~0.5 kWh |
| Cooking (microwave + kettle if you dare) | ~0.5 kWh | |
| Total battery draw | ~2.7 kWh |
Battery recommendation: 1 × 5.12 kWh battery (usable: ~3.9 kWh). About 70% utilised. This works, but there's less margin for error. If you're running a chest freezer or multiple TVs, consider 2 batteries.
Inverter: 5 kVA. At this stage, the loads stack higher in the evening and you need the headroom for simultaneous appliances.
System cost: $1,800–2,800
At Stage 6, your panels only have about 6 hours of production (10:00–16:00) to recharge the battery for 12 hours of outage. Make sure your panel array is large enough to fully recharge by afternoon. An undersized panel array is the hidden failure mode at this stage — the battery might be fine, but if it never fully charges, you start each evening a little shorter.
Stage 8: 18 Hours Off
Outage pattern: 00:00–06:00, 08:00–14:00, 16:00–22:00
The grid is on for 6 hours a day. Solar + battery isn't backup anymore — it's your primary power source.
| What | Calculation | Energy |
|---|---|---|
| Evening (6 hrs, 16:00–22:00) | 175W × 6h + evening cluster | ~1.7 kWh |
| Overnight (6 hrs, 00:00–06:00) | 120W × 6h (fridge, lights, router) | ~0.7 kWh |
| Midday gap (08:00–14:00, panels help) | ~50% covered by panels | ~0.5 kWh net |
| Cooking, extras | ~0.5 kWh | |
| Total battery draw | ~3.4 kWh |
Battery recommendation: 2 × 5.12 kWh batteries (usable: ~7.7 kWh). About 44% utilised across both. This gives you genuine 2-day autonomy for the loads that matter.
Inverter: 5 kVA minimum. Consider 8 kVA if you have a borehole pump or heavy loads.
Panel array: Size for the full daily load, not just the battery shortfall. You need enough panel capacity to both run the house during the limited solar window and fully recharge two batteries.
System cost: $2,800–4,500
At Stage 8, you're essentially running an off-grid system that occasionally gets a grid bonus. Size accordingly.
The Summary Table
| Stage | Hours Off | Battery Draw | Batteries (48V, 5.12 kWh) | Inverter | Price Range |
|---|---|---|---|---|---|
| Stage 2 | 4 hrs | ~1.2 kWh | 1 | 3 kVA | $800–1,400 |
| Stage 4 | 8 hrs | ~1.9 kWh | 1 | 3–5 kVA | $1,200–2,000 |
| Stage 6 | 12 hrs | ~2.7 kWh | 1–2 | 5 kVA | $1,800–2,800 |
| Stage 8 | 18 hrs | ~3.4 kWh | 2 | 5–8 kVA | $2,800–4,500 |
These estimates assume essential loads only — lights, fridge, TV, router, phones. If you're running a borehole pump, electric geyser, or kettle from battery, the numbers go up significantly. See the heavy loads section below.
Heavy Loads Change Everything
The table above covers a household running essentials. The moment you add heavy appliances, the battery math shifts dramatically.
| Heavy Load | Daily Energy | Impact on Battery |
|---|---|---|
| Electric kettle (3–4 boils/day) | +2.0 kWh | Nearly doubles essential battery draw |
| Electric geyser (150L) | +6.0 kWh | More than triples the battery requirement |
| Borehole pump (1.1 kW, 1 hr) | +1.1 kWh | Moderate, but surge demands a larger inverter |
| Electric stove (1.5 hrs/day) | +4.0 kWh | Requires 8+ kVA inverter and extra batteries |
A household at Stage 4 running essentials needs ~1.9 kWh from the battery. Add a kettle and a geyser, and that jumps to ~9.9 kWh — requiring 3 batteries instead of 1, and an 8 kVA inverter instead of 3.
The Smart Approach: Move Heavy Loads Off-Battery
Instead of buying a bigger battery to run everything, move the heavy loads to times when they don't touch the battery:
-
Kettle — Switch to a gas stovetop kettle or an LPG portable burner. This single change saves ~2 kWh/day and is the highest-impact optimisation for any solar household in Zimbabwe.
-
Geyser — Set a timer for 10:00–13:00 so it heats on live solar production. The water stays hot through the evening. Never heat your geyser from battery.
-
Borehole pump — Run it between 10:00–14:00 during peak solar into an elevated storage tank. Gravity feeds the house the rest of the day.
-
Iron, washing machine, vacuum — Schedule between 10:00–14:00 during peak solar hours. These appliances are fine on solar — it's running them from battery that's expensive.
Moving your kettle to gas and your geyser to a solar timer saves roughly 8 kWh/day. That's the equivalent of adding 2 extra batteries to your system — except it costs $30 for a timer and $40 for a gas burner instead of $1,100+ for batteries.
Why 48V LiFePO4 and Nothing Else
Every battery recommendation in this guide assumes 48V LiFePO4 (lithium iron phosphate). There's a reason for that.
Lead-acid batteries are cheaper upfront ($150–250 for a 100Ah 12V unit) but only tolerate 50% depth of discharge (vs 80% for LiFePO4), last 2–4 years instead of 10–12, weigh 3× more, and need ventilation due to hydrogen off-gassing. Over 10 years, lead-acid costs 2–3× more than lithium when you factor in replacements.
48V systems are more efficient than 12V or 24V. Higher voltage means lower current for the same power, which means thinner cables, less heat, less loss, and better inverter efficiency. Every serious inverter in the Zimbabwe market (Deye, SRNE, Growatt, Sunsynk) is built for 48V.
The standard unit — 51.2V nominal, 100Ah, 5.12 kWh — is what every calculation in this guide is based on. It's the default in the SolMate sizing engine because it's what the market has standardised on.
The Recharge Window Matters as Much as the Battery
A common mistake: buying enough battery for the evening but not enough panels to recharge it by afternoon. Your battery is only as useful as your ability to fill it back up before the next outage.
How Many Panels to Recharge Your Battery
The recharge window depends on your load-shedding stage. At Stage 2, you might have 8+ hours of good solar. At Stage 8, the effective recharge window shrinks to 4–5 hours (because some solar hours coincide with outage periods when the house is also drawing power).
| Stage | Effective Recharge Window | Panel Array to Recharge 1 Battery | Panel Array to Recharge 2 Batteries |
|---|---|---|---|
| Stage 2 | ~8 hours | 2–3 × 430W panels | 4–5 × 430W panels |
| Stage 4 | ~6 hours | 3–4 × 430W panels | 5–6 × 430W panels |
| Stage 6 | ~5 hours | 4–5 × 430W panels | 6–8 × 430W panels |
| Stage 8 | ~4 hours | 5–6 × 430W panels | 8–10 × 430W panels |
These assume Harare-area peak sun hours (~5.8 annual average) and account for system efficiency losses (~22% from temperature, inverter, wiring, dust, and mismatch).
At Stage 6 and above, panel array sizing becomes the constraint — not battery capacity. If your panels can't fully recharge the battery during the shortened solar window, you'll start each evening with less stored energy than the night before. After 2–3 days, the battery never reaches full charge and your usable capacity shrinks.
What Load Shedding Stage Should You Size For?
This is the real question. Do you size for your current stage, or plan ahead?
Size for one stage above your current reality. If you're currently experiencing Stage 4, size your battery for Stage 6. Here's why:
- Load shedding severity fluctuates. A Stage 4 area can jump to Stage 6 during peak demand months (June–August when heaters are running).
- Battery capacity degrades over time. After 5 years, a LiFePO4 battery retains about 90% of its original capacity. The extra headroom covers this.
- The cost difference between 1 and 2 batteries is $550–790 per unit. That's far cheaper than retrofitting later when you need to rewire and potentially upgrade your inverter.
The exception: If you're at Stage 8, you're already sizing for near-off-grid operation. The only step up from here is a fully off-grid system with 2–3 days of autonomy and a generator backup.
Generator Backup: When to Keep the Diesel
Solar + battery handles Stage 2–6 without breaking a sweat. At Stage 8, a generator becomes a legitimate backup consideration — not as your primary power source, but as insurance for the 2–3 worst weeks of the year.
A small diesel generator (3–5 kVA) costs $400–700 and can recharge your batteries in an emergency. Running it for 2 hours charges about 3–4 kWh into the battery — enough to cover an evening. At $1.50/litre diesel and 1.5L/hour consumption, that's $4.50 per emergency charge.
The solar system handles 95% of the year. The generator handles the 5% when consecutive overcast days coincide with heavy load shedding. This hybrid approach costs less than doubling your battery bank for edge cases.
Configure Your Load Shedding in SolMate
SolMate's sizing calculator includes load-shedding awareness. Set your stage (or define custom outage windows), and the tool adjusts battery recommendations to match your actual grid availability.
Size Your System
Calculate the right panels, batteries, and inverter for your home.
The settings page lets you configure your exact load-shedding pattern — choose a preset stage or define custom time blocks. Your daily planner then shows which hours you're on grid, on solar, or on battery.
Settings
Personalise your location, usage, and system preferences.
Key Takeaways
- Battery sizing depends on your load-shedding stage, not just your daily kWh. A Stage 2 household needs ~1.2 kWh from battery; Stage 8 needs ~3.4 kWh (essentials only).
- Evening outages are the critical window. That's when your loads are highest and your panels produce nothing. Size your battery for the evening, not the full day.
- Heavy loads (kettle, geyser, stove) change the math dramatically. Move them to solar hours with timers, or switch to gas. This is the single biggest cost saver.
- Panel array sizing matters as much as battery capacity. At Stage 6+, the recharge window shrinks. Undersized panels mean the battery never fully charges.
- Size one stage above your current reality. Load shedding fluctuates, and the cost of an extra battery now is far less than retrofitting later.
- 48V LiFePO4 is the only sensible choice for daily cycling. Lead-acid can't handle the depth of discharge load shedding demands.