The Solar & Inverter Dictionary

An inverter converts DC electricity (from batteries and solar panels) into AC electricity (what your appliances use). When you see "3.5kVA inverter", the kVA number is the maximum load it can power at any moment. Hybrid inverters — the type we install — also manage solar charging, battery charging from the grid, and priority switching between grid, solar, and battery automatically.

The battery bank stores energy so you can use it when the sun isn't shining or NEPA is off. Battery capacity is measured in kWh (kilowatt-hours) — the total energy it can hold. A 15kWh battery can, in theory, power a 1,500W load for 10 hours. In practice, you also factor in depth of discharge (DoD) and round-trip efficiency. We exclusively use LiFePO4 lithium batteries.

PV stands for photovoltaic — the technology that converts sunlight directly into electricity. Panels are rated in watts peak (Wp) — the output at ideal laboratory conditions (25°C, 1,000 W/m² irradiance). In real Nigerian conditions, a 620W panel produces roughly 500–560W at peak. To estimate daily output: multiply panel wattage × peak sun hours (Abuja ≈ 4.0–5.5 hrs/day depending on season). 4 panels × 620W × 4hrs = ~9.9kWh/day.

A transfer switch allows you to manually or automatically switch a circuit between two power sources — typically between the inverter output and direct NEPA. A manual bypass is useful for servicing: you can isolate the inverter for maintenance while keeping appliances running on direct grid power. An automatic transfer switch (ATS) is what hybrid inverters use internally to switch between grid, solar, and battery in milliseconds — fast enough that most appliances never notice the changeover. Some large installations have a separate external ATS panel for generator integration.

Tubular (lead-acid): Cheap upfront. Dies in 2–3 years. Only 50% usable capacity (you can only discharge to 50% before damaging the cells). Needs water top-ups every 1–2 months. Releases hydrogen gas — requires ventilation. Real 10-year cost: 3–4 replacements = ₦3.6M–₦4.8M. Lithium (LiFePO4): Higher upfront cost. Lasts 15–20 years. 90–95% usable capacity. Zero maintenance. No gases. Real 10-year cost: one purchase. The maths strongly favours lithium for anyone planning to stay in their home or office for more than 3 years.

Lithium Iron Phosphate — the specific lithium chemistry we use in all our installations. Compared to other lithium types (NMC, NCA used in phones/laptops/EVs), LiFePO4 is thermally stable — it does not overheat or catch fire under normal or abuse conditions. It trades some energy density for safety and longevity. 8,000–10,000 cycles vs. 500–1,000 for lead-acid. This is why we offer a 5-year warranty — the chemistry earns it.

One cycle = one full charge and discharge. A battery rated for 8,000 cycles at 90% DoD will complete 8,000 full cycles before its capacity drops below 80% of original. At one cycle per day, that's over 21 years. Real-world usage is typically less than one full cycle per day (especially if NEPA is present some of the time), so the actual lifespan is often longer. Always check what depth of discharge the cycle count is rated at — a "3,000 cycle" battery rated at 100% DoD is worse than a "5,000 cycle" battery rated at 80% DoD.

The percentage of battery capacity you actually use before recharging. A 15kWh battery used to 90% DoD gives you 13.5kWh of usable energy per cycle. At 50% DoD, the same battery gives only 7.5kWh. This is why lithium batteries provide nearly twice the practical energy of an equivalent-sized tubular battery, even if the label says the same kWh. We discharge our LiFePO4 batteries to 90–95% DoD regularly — the chemistry handles it without degradation.

The BMS is the electronics built into every quality LiFePO4 battery pack. It monitors each individual cell's voltage, temperature, and state of charge in real time, and takes protective action if anything goes out of range: it will disconnect the battery if a cell overcharges, over-discharges, overheats, or draws too much current. A BMS is why lithium batteries are safe and long-lived — without it, a lithium battery is genuinely dangerous. When evaluating batteries, ask whether the BMS is active balancing (moves energy between cells to keep them equal) or passive balancing (bleeds off excess from high cells). Active balancing is superior and extends pack life significantly.

These are the two most confused terms in solar. kVA is about instantaneous power capacity — how much load the system can handle right now. kWh is about stored energy — how long the system can run. Example: a 6kVA inverter can power up to 6,000VA of appliances simultaneously. A 15kWh battery holds enough energy to power those appliances for ~2.5 hours. You need both figures to properly size a system — kVA alone tells you nothing about runtime, and kWh alone tells you nothing about whether your appliances will even turn on.

kW (kilowatt) is a rate — power being consumed or produced right now. kWh (kilowatt-hour) is an amount — energy consumed or stored over time. A 1kW appliance running for 3 hours uses 3kWh. Your NEPA bill charges you in kWh. Your battery is sized in kWh. Your inverter and solar panels are rated in kW (or kVA). A simple way to remember: kW is the speed, kWh is the distance.

kVA is how inverters are rated — it's the apparent power the inverter can deliver. For resistive loads (bulbs, heaters, kettles), kVA ≈ kW. For inductive loads (motors, ACs, pumps, fridges), the actual usable power in kW is lower than the kVA figure due to power factor. A typical power factor is 0.8, so a 6kVA inverter delivers about 4.8kW to motor loads. This is why we always ask about your AC and motor appliances before recommending an inverter — an undersized kVA rating is the #1 cause of inverter overload trips.

A kilowatt is 1,000 watts. It's the unit for measuring power — the rate of energy use or generation at any instant. Your inverter's output capacity is measured in kW (or kVA). Solar panels are rated in watts peak (Wp) — a 620W panel is 0.62kW. Your fridge draws perhaps 80–180W. Your AC draws 700–1,500W. Add up all the appliances you want to run simultaneously to find the peak kW demand — that determines your minimum inverter size.

A kilowatt-hour is the energy used by a 1kW appliance running for one hour. Your NEPA meter counts kWh. Your battery's capacity is in kWh. To calculate your daily consumption: for each appliance, multiply watts × hours used per day ÷ 1000. A 100W TV running 8hrs = 0.8kWh/day. A 1,100W inverter AC running 6hrs = 6.6kWh/day. Sum these up for your total daily kWh — this is the number that determines what battery size you need.

An older unit still printed on many batteries — especially tubular lead-acid. It measures charge capacity at a specific voltage. To convert to kWh: kWh = (Ah × Volts) ÷ 1,000. A 200Ah 48V battery holds 9.6kWh. The catch: lead-acid Ah ratings are quoted at a 20-hour discharge rate (C20). Discharge it faster — as inverters typically do — and the usable capacity is 20–30% less than the label suggests. LiFePO4 batteries are far less affected by discharge rate, which is another reason the kWh comparison between battery types favours lithium more than the headline numbers suggest.

Power factor (PF) is the ratio of real power (kW — what actually does work) to apparent power (kVA — what the inverter sees). For purely resistive loads like bulbs, heaters, and kettles, PF = 1.0. For inductive loads with motors — ACs, fridges, pumps, washing machines — PF is typically 0.7–0.85. This is why a "5kVA inverter" does not mean "5kW for every appliance." A 1.5HP AC draws about 1,200W of real power but presents 1,400–1,600VA of apparent load on startup. Ignoring power factor when sizing an inverter is the single most common sizing mistake.

A hybrid system connects to the grid and has solar panels and batteries. The inverter intelligently decides where to source power in real time: solar first (free), then battery (stored solar), then grid (NEPA or generator) as a last resort. When solar is producing more than you are consuming, the excess charges your batteries. This is the configuration we install in virtually every home and office — it gives you the lowest electricity cost and the most resilience because you are never fully dependent on any single source.

An off-grid system has no connection to NEPA at all. It runs entirely on solar and battery. These are sized for the worst-case scenario — multiple consecutive cloudy days with no sun — which means they require significantly larger battery banks and more panels than a hybrid system of equivalent capacity. Off-grid is the right choice for remote locations where grid connection is unavailable or prohibitively expensive. For most urban and peri-urban Nigerians, hybrid is more cost-effective because NEPA — even unreliable — still provides a free top-up on poor solar days.

A grid-tied system has solar panels but no battery storage. It feeds excess solar power directly into the grid (and in markets with net metering, you get credited for it). In Nigeria, this is the least common residential configuration because it provides zero backup — when NEPA cuts, the system shuts down entirely as a safety measure (anti-islanding). Grid-tied makes sense for businesses that run during the day and want to reduce their NEPA bills, but have a generator for backup rather than relying on batteries.

Peak Sun Hours is the number of hours per day that solar irradiance averages 1,000 W/m² — the standard test condition for panel ratings. Abuja averages 4.0–5.5 PSH depending on season (dry season is higher, rainy season lower). Lagos and coastal cities average 3.8–4.5 PSH. To estimate daily solar generation: multiply total panel wattage (kWp) by local PSH. A 4kWp array in Abuja with 4.0 PSH generates roughly 16kWh/day before losses. We use 4.0 PSH as our conservative planning figure — this means real performance in dry season will typically exceed our estimates.

Installing more solar panel capacity (kWp) than the inverter's rated MPPT input is called oversizing or clipping. It sounds wasteful, but it is often deliberate. Panels only hit their rated output for a few hours around solar noon on a clear day. For most of the morning, evening, and on cloudy days, the array operates well below the inverter's MPPT limit. Oversizing by 20–40% means the system hits near-maximum charging output over a longer window each day — your battery fills faster. The slight clipping at peak noon is a worthwhile trade-off. We commonly install 4–5kWp of panels on a 3.5kVA hybrid inverter.

A string is a series of solar panels wired positive-to-negative in sequence. Each panel's voltage adds to the next, while the current stays the same. A string of 4 panels × 49V each = ~196V string voltage. Strings are then connected in parallel to increase current. Your inverter's MPPT input has a maximum voltage limit (e.g. 500V) — exceed it and you destroy the controller. String design is a calculation, not a guess. All Tinitop systems are string-designed before a single wire is run.

Maximum Power Point Tracking. The algorithm in your inverter's solar charger that continuously adjusts the electrical operating point of the solar panels to extract maximum power as conditions change (clouds, temperature, angle of sun). A good MPPT controller recovers 10–30% more energy than a basic PWM (Pulse Width Modulation) charger. All Tinitop hybrid inverters include dual MPPT — two independent trackers so you can have panels on different roof orientations without them pulling each other down.

Undersized wiring is a fire hazard and causes voltage drop that reduces system efficiency. The key rules: DC battery cables carry very high current at low voltage — a 48V system drawing 100A needs thick cable (16–35mm²). AC output cables carry lower current at 240V and are easier to size. Solar string cables use MC4-rated 4mm² or 6mm² DC cable. We size all cables to carry 125% of expected maximum current with less than 1% voltage drop. Never let an installer run thin "any cable" for battery connections — this is how inverter fires start.

Open Circuit Voltage is the voltage a solar panel produces when it is in full sunlight but not connected to any load. It is the highest voltage the panel can produce. You will see it on every panel's spec sheet (e.g. Voc = 49.2V for a typical 620W panel). This number matters when wiring panels in series — a string of 4 panels has a Voc of 4 × 49.2V = 196.8V. Your inverter's solar input must be rated above this figure, or you will damage the MPPT controller the moment the sun comes out on a cold morning (when Voc is at its peak).

Solar panels lose efficiency as they heat up. The temperature coefficient (typically around −0.35% per °C) tells you how much output drops for every degree above the lab test temperature of 25°C. On a hot Nigerian afternoon, a panel on a metal roof can reach 65–70°C — that is 40–45°C above the test point, meaning roughly 14–16% less output than the rated wattage. This is why Abuja's practical peak sun hours are closer to 4.0hrs than the theoretical 5.5hrs in summer — heat is always eating into your numbers.

No inverter converts energy at 100%. A quality hybrid inverter runs at 93–97% efficiency — meaning for every 100W drawn from the battery, 93–97W reaches your appliances; 3–7W is lost as heat. This efficiency curve also drops at very low loads (running a single bulb from a 6kVA inverter is inefficient). When sizing a system, we factor in round-trip efficiency: energy in from solar → stored in battery → out through inverter. The combined efficiency of a good LiFePO4 + hybrid inverter system is typically 88–92%.

Earthing connects the metal chassis of your inverter, battery enclosures, and panel frames to a physical earth rod driven into the ground. It serves two purposes: safety (gives fault current a safe path to earth instead of through a person) and surge protection (provides a return path for lightning-induced transients). An unearthed solar system is a live hazard — if any insulation fails, the entire metal chassis becomes live. Proper earthing is not optional; it is required by the Nigerian Electricity Supply and Installation Standards (NESIS) and is part of every Tinitop installation.

A surge protection device on the DC solar cable side clamps voltage spikes caused by nearby lightning strikes before they reach the MPPT input of your inverter. Nigeria has one of the highest lightning strike densities in the world — particularly in the middle belt and south. A rooftop panel array is essentially a large antenna during a thunderstorm. A ₦15,000–₦25,000 DC SPD at the combiner box can protect a ₦1.5M+ inverter. We recommend it for any panel mounted on a rooftop or structure taller than the surrounding buildings.

The duration of a loan — how many months you have to repay. Longer tenor = lower monthly payment but more total interest paid. Shorter tenor = higher monthly payment but less total interest. For our 6-month flat-rate plan, the total interest is lower than for the 24–48 month reducing-balance plans. If you can afford the higher monthly payment of a shorter tenor, it is almost always cheaper overall.

The upfront deposit you pay when using a reducing-balance loan plan. Our 24, 36, and 48-month plans require 20% equity — you pay 20% of the system cost upfront, and we finance the remaining 80%. Equity reduces the lender's risk and reduces your loan principal, which lowers your monthly payments. It also means you have immediate ownership stake in the system.

A loan repayment method where interest is calculated on the remaining loan balance each month, not the original amount. As you make repayments, the principal reduces, so each month's interest charge also reduces. This results in lower total interest paid compared to a flat-rate loan of the same tenor and interest rate. Our 24, 36, and 48-month plans use reducing balance — suitable for customers who want long-term financing with fair interest treatment.