I suspect you also have a large system on the roof.
On sunny days with clouds, the yield fluctuates enormously during the day. This does not matter with a large system because you still stay above the base load. With a small balcony power plant, I could imagine that without a storage unit you would fluctuate between consumption and surplus during the day, thereby increasing the number of cycles.
It depends on when charging can take place. If it happens during the day, e.g., on [HO]-days, the car itself acts as a storage. This is of course optimal because the electricity is used when it is generated and fewer conversion losses occur. The number of cycles for the storage decreases as a result.
If one regularly arrives home only in the evening and drains the fully charged storage again, the number of cycles would increase instead. While this has a positive effect on the calculation for or against the storage, overall the total consumption is higher due to the additional conversion losses.
I currently mostly charge my hybrid on [HO] days as well. With storage, I could charge in the evening, and my wife could use it on my [HO] days. With two electric vehicles/hybrids, however, it does not matter, because then charging can be done on weekends or on [HO] days. It’s all very individual, and the demand will also change within the amortization period of photovoltaic systems/storages.
For example, I already assume that we will eventually operate both vehicles electrically. Possibly, a third vehicle from the child will be added for a while as well.
The number of cycles results from the usage profile. Of course, future plans and price developments can be anticipated in the usage profile; I consider that crystal ball gazing.
Our e-car is used by 3 people - it is the preferred vehicle for trips up to 100km. To ensure that everyone can leave at any time, charging takes place at home when one gets out. This is not cost-optimized, but it maximizes spontaneous availability and avoids additional coordination. The number of cycles of the home storage has decreased significantly since we have had the e-vehicle.