The patent-pending XEYAR architecture lets a 100 A standard service drive up to 720 kW of EV charging — avoiding 6–18 months of utility upgrade work. Here's how the shared DC bus actually works, and why it changes the deployment math for fleet depots, retail sites, and corridor hubs.
Most DC fast-charging projects don't die because the chargers are too expensive. They die because the utility upgrade quote comes back at six figures and an 18-month timeline — and the project economics never come back from that.
The standard playbook for putting four 180 kW DC fast chargers at a site is to call the utility, ask for 800 amps of new service, and start writing checks. The transformer needs upsizing. The service entrance needs rebuilding. There's a queue. There's a contractor. There's a permit cycle. And the numbers stop making sense long before the chargers turn on.
The XEYAR battery-buffered architecture changes the question. Instead of asking the grid to deliver peak charging power on demand, it asks the grid to deliver average charging power continuously, and uses an on-site battery to handle the peaks. The result: a 100 A standard commercial service can drive a 720 kW cluster of DC fast chargers without a panel upgrade.
Here's how the architecture works, why the math is favorable, and where the limits are.
A 180 kW DC fast charger draws roughly 220 amps at 480V three-phase when it's running at full output. Four of them, simultaneously, draw close to 880 amps. That's a service entrance most retail sites, fleet depots, and small commercial properties simply don't have — and getting one means a transformer upgrade from the utility, a new service drop, panel work, and inspections. Industry timelines for that work commonly run 6 to 18 months in the United States, and capital costs frequently exceed $100,000 before any chargers are installed.
The deeper issue: those four chargers are almost never running at full output simultaneously. Real-world utilization at most retail and fleet sites looks more like one or two ports active at a time, with peak coincidence below 50% even at busy hours. So the upgraded service spends most of its life delivering a fraction of its capacity — you pay for the peak you almost never hit.
XEYAR replaces the “every charger pulls from the grid directly” topology with a shared DC bus and a stationary battery in between. The grid feeds the battery at a steady, modest rate. The battery feeds the chargers at whatever burst rate they need.
In a typical four-port XEYAR cluster, the configuration looks like this:
Aggregate dispense capacity: up to 720 kW peak, all from a service that would normally support a single Level 2 line.
The economics work because EV charging energy is — over the course of a day — modest. A single 180 kW charger session typically delivers 30 to 60 kWh and lasts 15 to 25 minutes. A site that handles, say, 60 sessions in a 24-hour day delivers around 2,000 kWh. A 100 A 480V three-phase service can pull roughly 80 kW continuously, which is 1,920 kWh over 24 hours.
The arithmetic is close enough that battery sizing becomes the operational lever rather than service sizing. A larger battery handles longer peaks; a smaller battery handles shorter ones. The grid input stays the same.
Three things shift in a way that matters:
Standard 100 A 480V services are routine work for any commercial electrician. There's no transformer upgrade, no service drop redesign, no utility engineering review. Permits move at the speed of any other commercial electrical job — weeks, not quarters.
The battery pack is not free, but it's a known, depreciable line item with a five-to-fifteen-year service life depending on chemistry. The avoided utility upgrade is a non-depreciable sunk cost that varies wildly by site. Trading a variable-cost upgrade for a fixed-cost battery makes financial models more predictable, which makes financing easier.
In most US commercial tariffs, demand charges are billed on the highest 15-minute interval of grid draw in the billing period. A direct-grid 720 kW cluster sets that peak the first time anyone uses it. A XEYAR cluster never sees that peak at the meter — the battery absorbs it. Demand charges drop to whatever the steady grid input is.
XEYAR is not a free lunch. Three constraints matter:
| Constraint | What it means |
|---|---|
| Sustained throughput | If a site's daily energy demand exceeds what the grid input can refill in 24 hours, the battery slowly depletes. XEYAR is for peak-shaving, not for sites that genuinely need 800 amps of continuous draw. |
| Battery footprint | The battery cabinet is real hardware that needs a pad, ventilation, and code-compliant siting. It's roughly the size of a utility transformer. |
| Round-trip efficiency | Energy in → battery → vehicle has a small efficiency penalty (typically 5–10%) versus direct grid → vehicle. For most sites the avoided demand charges more than offset this; for industrial sites with already-low demand charges, the math tightens. |
The architecture shines for sites where utility upgrades are slow, expensive, or politically blocked — which describes most retail, hospitality, and small-to-mid fleet depots in North America today.
Three diagnostic questions cut through most of the noise:
The thing we keep telling buyers: don't size for peak power. Size for daily energy. The peak is what you build the architecture around — not what you build the service around.
— MÖTEN evfc Engineering team
The full XEYAR product page covers cabinet specifications, supported configurations, and the four typical site profiles. For pricing on battery-buffered clusters specifically, the Battery Buffered product page has the current configurations. For sites where a utility upgrade is unavoidable but you want to phase it, the DC Fast Chargers page covers conventional grid-tied configurations as well.
If you want a sanity-check on whether your specific site is a XEYAR candidate, our engineering team will look at your service capacity, expected utilization, and tariff for free — send the site address and we'll come back with a yes/no in two business days.
Send us your service capacity, expected sessions, and tariff structure. We'll tell you in two business days whether battery-buffered makes sense — or whether a conventional grid-tied build is the better answer.