I personally don’t install a lot of these, and so wouldn’t call myself a sonnen expert, but I know they are a premium battery. And with add-ons can provide a lot of functionality.
They have great lifetime specifications and a great warranty.
I like the fact they are so modular, and offer a good range of system sizes in 2kWh blocks I believe.
The output power, is a little small for a large house, but fine for smaller economic users, and for backup especially this is a bit of a let down. People have a lot of electrical appliances nowadays.
It comes down to the individual customers wants and needs as to whether this battery is ideal for them.
But for many people it is a great option. And definitely fills a all in one niche for smaller modular batteries.
The Tesla for example only comes in the one size, and so excludes the range of people looking for something smaller.