Experiences with Caterva Sun battery storage

do you happen to have a link for the software exchange of the charging management? I can hardly find anything here in the forum. Thanks in advance!

Links are not allowed here and yes, the forum is a bit difficult. Take a look through the "big" threads about the storage, you will find the corresponding references there.

Hello everyone,

thank you very much for the previous assessments of the Caterva-Sonne. I have dealt with it and made the following calculation:

Purchase price of the Caterva-Sonne €36,888 gross (easier to calculate) Electricity demand with heat pump power 10,000 kwh per year. Own photovoltaic system with 5kwp, so about 5,000 kwh of own production. That means we can produce almost half of the electricity ourselves. Costs around €6,000 for the photovoltaic system, making about €42,000 investment all inclusive.

For the 20 years I receive €1,000 per year, so €20,000. I only have to pay for 5,000 kwh per year, so about €1,500 per year. That is another €30,000 for 20 years.

Simple calculation: €42,000 investment (Caterva + photovoltaic system) + €30,000 electricity (from the grid at about 27.5 cents per kwh) - €20,000 premium from Caterva (€1,000 per year) = €52,000 for 20 years of electricity with Caterva

Now the calculation without Caterva €6,000 investment for photovoltaic + €41,250 electricity demand (7,500 kwh x 27.5 cents x 20 years with 2,500 kwh own consumption) - €6,000 feed-in tariff (2,500 kwh x €0.12 x 20 years) = €41,250 for 20 years with photovoltaic system without battery storage -> Somehow it doesn’t quite add up.

Or am I missing something?

Sure, if you calculate the electricity price per year with +3% and so on, you can make the numbers look good. Actually, this only makes sense for large electricity consumers or commercial customers who can then calculate it net and have various depreciation options. A farm or a hotel should be able to generate a profit over 20 years with it.

Purchase price of the Caterva-Sonne €36,888 gross (easier to calculate)


Without off-grid system, a Caterva Sonne costs €27,500 net, i.e. €32,725 including VAT

Electricity demand with heat pump electricity 10,000 kwh per year.

Own photovoltaic system with 5kwp, i.e. approx. 5000 kwh own generation.

That means we can generate almost half of the electricity ourselves.

Costs approx. €6,000 for the photovoltaic system, making approx. €42,000 investment all inclusive.

Investment €38,725 according to my calculation

For 20 years I receive €1,000 per year, i.e. €20,000.

If gross, then please everything, so €1,190 equals €23,800

I only have to pay for 5000 kwh per year, approx. €1,500 per year.

That is another €30,000 for 20 years.

Without price increase, I consider unlikely.

Simple calculation:

€42,000 investment (Caterva + photovoltaic system) €38,725

+ €30,000 electricity (purchased from the grid at approx. 27.5 cents per kwh)

- €20,000 premium from Caterva (€1,000 per year) €23,800

= €52,000 for 20 years electricity with Caterva €44,925


Now the calculation without Caterva

€6,000 investment for photovoltaic

+ €41,250 electricity demand (€7,500 kwh x 27.5 cents x 20 years with 2,500 kwh own consumption)


Based on experience, own consumption for photovoltaic systems is between 25 and 30 %


5000 kWh production results in 1500 kWh self-consumption

8500 kWh * 27.5 cents * 20 years equals €51,000


- €6,000 feed-in tariff (2,500 kwh x €0.12 x 20 years)

€8,400 feed-in tariff

= €41,250 for 20 years with photovoltaic system without electricity storage

-> Somehow that doesn’t quite add up.??

Remaining €48,600 compared to €44,925


Electricity price increase 2016 at Bayernwerk 14%, naive to believe that the electricity price stays constant.

But every percentage point worsens your calculation.

Optimal would of course be to size the photovoltaic system larger.

Anyone expecting an increase in electricity prices should also take into account the interest-free loan from catavera as well as maintenance costs, repairs, and risk of insolvency.