Charging and storage belong in the same design

The connection is the constraint

A charging site is sized by its peak, but it is billed and connected by its capacity. A location with a modest connection can still deliver high power to a vehicle — briefly — if there is somewhere to draw the difference from. That somewhere is storage.

Treating the battery as an accessory bolted on afterwards produces the worst of both: an installation that costs more, occupies more space and still cannot deliver peak power reliably, because the two systems were specified against different assumptions.

What changes when they are designed together

When charging and storage are one architecture rather than two products sharing a forecourt, several things stop being problems:

• The power conversion stage can be shared instead of duplicated, which removes a conversion step and its losses.
• Peak demand is served from the battery, so the grid connection is sized for average draw rather than worst case.
• Thermal management is designed once, for a known combined load, rather than twice for two enclosures that end up next to each other.
• The control system has one view of the site, so it can decide what to charge, what to discharge and when — rather than two controllers negotiating.

It is a systems problem, not a product choice

None of this is an argument for a particular product. It is an argument for deciding the architecture before selecting the equipment, because the architecture is what determines whether the equipment can do the job.

The practical version: work out the site's real duty cycle first — how many vehicles, at what power, at which times — then size the connection and the storage against it, and choose the charger last. Doing it the other way round is how forecourts end up with capacity they cannot use.