How to Run a Whole House on Solar in Khartoum

You are not looking for a backup system. You are looking for the whole thing: the fridge, the fans, the lights, the water pump and the phones, running because you built the supply yourself rather than because the grid happened to be on. That is a different purchase from a UPS, and it turns on a row most people never read.

Here is the short version. An off-grid house is sized by three numbers, and only one of them is the one buyers ask about. The first is surge - what the inverter will carry for a few seconds while a fridge compressor or a pump motor starts. Across our Felicity range that row reads 2×rated for 5 seconds on the IVPS, IVPM, IVEM, IVBM and IVCM families, 2×rated for 10 seconds on the IVAM, IVGM and smaller T-REX hybrids, and 1.5×rated for 10 seconds on the large three-phase machines. The second is battery energy, because in a house with no grid the evening is paid for entirely out of the pack. The third is charge current, because whatever you took out overnight has to go back in tomorrow. Get the surge wrong and the system trips; get the battery wrong and it dies at 2 a.m.; get the charging wrong and it never fully recovers.

We are an authorised Felicity Solar distributor and we supply Sudan, including Khartoum, Omdurman, Port Sudan, Kassala and Nyala. Send us a list of what you actually need to run - not a wattage guess, just the appliances - and we will size it against the published rows: WhatsApp +971 4 255 0887, +971 4 255 0887, or sales@felicitysolar.me.

Why the fridge decides the inverter, not the total

Add up the labels on everything in the house and you get a number. That number is almost never the number that trips the inverter. Anything with a motor in it - a fridge compressor, a freezer, a water pump, a washing machine, an air cooler - draws far more current in the instant it starts than it does while it runs. It lasts a moment. It is also the moment your system either carries the load or shuts down and beeps.

This is why the surge row exists, and why an inverter that looks comfortably oversized on paper can still refuse to start a pump. The manufacturer publishes two things: how far above the rating the machine will go, and for how long. Both halves matter. Twice the rating for five seconds is a real promise; twice the rating with no time attached would be marketing.

What the surge row says across the Felicity range

Read it against the machine's own rating and it becomes a purchase decision. The IVPS10048 states 8 kW rated output power and 10 kVA rated apparent output power, and carries double that for five seconds. The IVEM8048-II states 8 kW and 8 kVA on the same terms. The IVEM5048 is a 5 kW machine, and the IVEM12048-11 a 12 kW one. Twenty-seven listings also carry an explicit motor start capable: yes row - every IVPS, IVPM, IVEM, IVBM and IVCM listing in the range - which is the manufacturer saying out loud what the surge figure implies.

What happens when you ask for more than it has

The interesting part is that these machines do not simply trip. They publish a ladder, and the ladder tells you how the system will behave on a bad afternoon rather than how it behaves on a good one.

The IVPS5048 states an overload trip time of 10 seconds above 105% load and 5 seconds above 150%. The IVEM8048-II publishes four steps instead of two: 10.5 s above 105%, 7.5 s above 120%, 5.5 s above 150% and 0.2 s above 200%. That last figure is the one worth understanding. A brief 200% draw - a motor starting - is inside the surge window. A sustained 200% draw is a fault, and the machine disconnects in two tenths of a second rather than cooking itself. Both behaviours come from the same row.

How much battery does a house with no grid actually need?

We are not going to hand you a kilowatt-hour figure for "a house in Khartoum", because a house is not a unit of measurement. What we can do is give you the arithmetic and the pack sizes, so you can do it honestly in ten minutes.

Write down each thing you need to run after dark, its wattage from its own label, and the hours it runs. Multiply and add. That total, in watt-hours, is what has to come out of the battery every night, and in a house with no grid there is no second source to quietly cover the difference. Then add the daytime load that the panels will not be covering directly.

Two rows on that table are worth more than the headline capacity. Depth of discharge tells you how much of the nameplate energy you are actually allowed to use - above 95% across these packs, which is why a lithium pack of a given size does more work than a lead-acid one of the same size. And cycle life is where the wear is counted: 6,000 cycles is a number of charge-and-discharge rounds, not a number of years, so a house that empties the pack every single night uses it up faster than one that half-empties it. Every one of these packs carries a built-in smart BMS with a breaker and a fuse, and reports over CAN and RS485 to the inverter.

Putting back tomorrow what you took out tonight

An off-grid house lives or dies on this and almost nobody checks it before buying. If the bank is deep and the charger is small, you will start every evening from a pack that never got full.

On the solar side, the IVEM5048 states a maximum solar charging current of 100 A and a maximum PV input power of 6 kW. The IVEM6048-II states 120 A of solar charging and 7.5 kW of PV. The IVEM8048-II states 150 A. The IVEM12048-11 states 240 A. The IVPM7548 combines 120 A of solar charging with 60 A of utility charging. The IVBM10048P1G1 states 200 A of solar charging and a maximum AC charge current of 200 A.

Against the batteries: the FLA48200 states a recommended charge and discharge current of 120 A and a peak of 150 A for 15 seconds; the FLA48300 a peak of 200 A for 15 seconds; the FLA48400TG1 a maximum continuous 200 to 250 A and a peak of 300 A for 15 seconds. Match the charger to the pack, not to the brochure.

Heat is a published row, not a complaint

Khartoum and Omdurman are hot, and heat is on the specification sheet in two separate places that people tend to merge into one.

On the inverter, the operating temperature range is the ambient air the box is allowed to sit in. Every IVPS and IVPM listing states 0 to 40 °C. The IVEM5048 states 0 to 55 °C, the IVEM8048-II -10 to 50 °C, both IVBM models 0 to 50 °C, and the IVAM range -40 to 60 °C with derating above 45 °C. A 40 °C machine is not a bad machine, but it belongs in the coolest ventilated room you have, not in a closed store cupboard against a west wall.

On the battery, there are two ranges and they are different from each other. The FLA packs state a charging temperature range of 0 to 55 °C and a discharging range of -20 to 55 °C, and the FLA48400TG1 additionally names 20 to 30 °C as its optimal operating temperature. A pack living permanently at the top of its range is inside its rating and is still not where it does its best work.

Where the box goes, and the mistake that dust makes

One more row before you drill anything: the IP rating. The IVPS, IVPM, IVEM and IVCM families are IP21, and the FLA and LPB battery packs publish a protection degree of IP21 as well. That first digit - the 2 - means the enclosure is not dust-protected. In a dusty city that is not a detail, and it is the single most common avoidable mistake in an off-grid install. The IVAM and IVBM inverters are IP65, as are the FLB wall packs. We have written the whole rating table up in the guide on indoor and outdoor ratings, and it is worth five minutes before the installer arrives.

A shopping order that works

Start with the biggest motor in the house and pick an inverter whose rating plus its surge row covers it comfortably - the IVEM8048-II and the IVPS10048 are the usual answers for a full house, with the IVEM5048 for a smaller one. Then size the pack from the watt-hours you wrote down, using the FLA48300 or FLA48400TG1 as building blocks. Then check the charge current at both ends. Then decide where the boxes live, using the IP rating rather than the free wall. The whole range is on the inverters page and the batteries page, and we will do the arithmetic with you if you send the appliance list.