3kW Off Grid Solar System In Kenya

Munene Kasina asked me a question about his system through email.

He wanted to run his farm completly off grid because there are no power lines available.

The farm under construction

These are the loads Munene wants to power:

  • 2 Fridges: 250W x 8hours x 2 fridges = 2000Wh
  • 2 TV’s: 150W x 4hours x 2tv’s = 1200Wh
  • 2 Laptops: 50W x 8h x 2laptops = 800Wh
  • 12 LED Lights: 5W x 8h x 12 lights = 480wh
  • Inverter idle draw: 25W x 24h = 600Wh

We have a total daily power consumption of 5080Wh.

Munene’s farm is located in Kenya with the following sunhours:

Sunhours in Nairobi Kenya
Sunhours in Nairobi Kenya

I then used my off grid solar calculator to determine how many batteries he needs to run this system. Using the following metrics:

  • 48V battery
  • 1 day of autonomy (budget constraints)
  • 4 sunhours (worst case scenario)

We need a 48V 134Ah lithium battery and 1300Watts of solar panels to support the loads with one day of autonomy.

Munene has chosen a 3kW Growatt hybrid inverter (SPF-3000 TL HMV-48).

Here is the diagram of the system:

Schematic of the 3kW system

We can see that the solar panels are wired in a 2S2P configuration, this means 2 panels in series and then in parallel.

From there it goes into a DC breaker and there is a SPD (surge protection device) that’s installed if there is an over-voltage from a lightning strike. This will protect the inverter from over-voltage.

We can see that we have an AC breaker in the same box, according to European and united states electrical regulations, these need to be separated. But this could be legal in Kenya. The installation was done by a company, so i assume they know what they are doing.

The DC solar power goes into the hybrid inverter’s MPPT input. Cables then go into the battery and AC out goes to a change over switch. I’m not sure what the change over switch does, But i assume it turns off the AC power. It then goes into an AC breaker before going to the consumer unit.

The system upon completion:

3kW Growatt inverter + 5kWh lithium battery

4 pieces 435W solar panels are used in a 2S2P configuration. They are monocrystalline from Jinko for a total of 1740Watts.

Solar panels on the roof

If you have questions about the system, feel free to ask them in the comments below so we can get a discussion going.

Leave a Comment