Many people ask how much power they need.
This is something that can only be answered by analyzing your situation.
It will depend on which appliances you use, do you use them at same moment, weather conditions, ….
If you have airco’s and summer is very hot, no need to say you will use a lot more energy.
Also there is a big difference in quality and efficiency of appliances. An inverter heat pump airco from Daikin will pull much less energy than a standard Qlima airco.

Some basic calculation need-to-knows.

  • Volt x Ampere = Watt. For example 220 Volts, 10 Amperes will result in 2.200 Watts.
  • If you have Wh or KWh it indicates how many power you can draw in 1 hour. So if you have a 1000Wh battery, and you pull 1000W (for example your microwave oven) it will run for 1 hour.
  • Some type of batteries such as AGM batteries (car batteries) can only be used from 100 % till 50 %. So if you have a car battery 80 Ah you have total power 12.8 V x 80 Ah = 1.024 Watt, but you can only use 50 % so 512 Whr. So in this case the microwave can run for 30 minutes.
  • Lithium ION, LiFePo4 batteries can be use fully. So a Lithium Car Battery same power, you are able to run your microwave for 1 hour.
  • Sealed, AGM, Acid batteries can be charged let’s say 250 times. A lithium ION battery can be charged 500 to 800 times. A LiFePO4 battery between 3000 and 6500 cycles.

Let’s take a current question “Can I run this appliance eg coffee machine with for example a 3 KWh battery” as example.
There are 3 things to consider.

  • Appliances sometimes at startup require more power. For example an airco system when switching on will pull for a very short time much more power. Therefore you can count on the inverters “Surge Power”. Surge Power is the power that can be delivered for a couple of seconds.
  • Let’s take the example of the coffee machine. I have in my car an Nespresso Machine. It pulls when heating up 1.100 Watts. In my car I have an Goal Zero 3KWh battery with 1500 Watts continuous power.
    So in theory I can run the coffee machina 3000 Wh / 1100 Watts = 2 hrs 43 minutes.
    BUT it will only draw 1.100 during warm up and this is for 15 to 20 seconds. Afterwards it goes to 140 Watts during making of coffee. So in real life I can make a lot of coffees with my battery.

Current Setup – Example

I will use my own situation as example.

I live in a 465 m2 home (5000 square ft) and my average consumption is 6000 KWh per year, which is 16.5 KWh per day. As we have a night / day meter I know my consumption is more or less 4 KWh during night and 12.5 KWh during day.
Heating is on gas, but we use Airconditioning during summer and sometimes we use it to heat.
Cooking is also electric (induction), 4 airfryers and traditional oven.

Solar Panels and Batteries

To date I have 12 solar Panels 380 Watts peak each attached to a 5KW Hybrid SolarEdge X1.
This produces depending on weather between 9 KWh (cloudy and rain) till over 30 KWh per day.
Due to the quality of the BEEL panels they peak a little over 400 Watts.

There is also a TRIPLE battery connected 6KWh and 2 1.5 KWh batteries.
For now the batteries are used as backup in case of grid loss. In my case this should be sufficient because at night I use the batteries and during the day my panels produce enough power to fully charge the battery and provide electricity for normal use.

Future upgrades

More solar panels & batteries

First of all I am planning to add more TRIPLE batteries. Probably 2 extra batteries till 18KWh batteries.

Carport to extend my garden house

I will install a 6 by 7 meter carport with more or less 24 panels with a separate Hybrid Convert SolarEdge X3 10KW.
This will produce between 20 KWh and 60 KWh per day.


60 KWh is enough to produce enough energy for my EV.
It will be a Ford F-150 Lightning with 150KWh battery and bidirectional connections. The F150 is able to provide electricity to the grid as well.

The panels will be place on a wooden Carport, similar to my actual garden house.

Heat Pump Boiler

For heating I will install a heat pump boiler producing warm water for house hold and for heating.
At that time I will be completely independent.
The water is from ground. I have a 12 meter deep system to get ground water.

Alternative Solutions

Portable Solutions (Solar Power Generators)

There are now a lot of mobile solutions which are ideal RV, tiny houses, camping or in case if you rent a house and you don’t want or if you are not allowed to make modifications.

These are portable Batteries with integrates inverter and MPPT solar charger.
They can go from small systems like 300 watts and weighing 2 kg till very big ones with 25KWh battery.
The large ones can delivery 7KW of continuous power.

Example Delta 1300

Example : EcoFlow Delta 1300. 1280 Ah battery, 1800 Watts output

Feasibility Off-grid

Off grid typeTechnical FeasibilityLegal Feasibility (BE)
ElectricityEasy, average investment 1 EURO per Watt including batteries. Cost over 10 yrs 0,1 EUR per watt vs 0,27 EUR per watt from provider. The bigger the installation, the lower the price per watt.In most European Countries it is mandatory to have a subscription
HeatingThere are several ways. Heat Pump Systems are the most efficient solutions in combination with solar powerRelated to electricity but no mandatory subscription
WaterUsing grond water pump power by solar or wind energy. Needs conversion of installation.
Recommendation to use Active Carbon Water Filters
No mandatory subscription but installation needs to be approved.


Beel pure black shingled 380 Watt panel

Inverters Battery Kit 12KWh