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When a site owner asks us, “I have a plot beside the national highway; can a few Scharge chargers go there?”, the answer always begins with a question in return: what is the power supply like there?
The charger is the part the driver sees. The part that decides whether the charger can run lies underground and inside the electrical cabinet. The second round of signing at the Signing Ceremony on 09/09/2026 was about exactly that part.
The document defines a “charging station” as an assembly
The Memorandum of Understanding between SPT Group (Saigon Postel) and XECO, which we witnessed, has the full title of cooperation on investment in chargers and low-voltage infrastructure for the Scharge Project network. The two parts sit side by side in the title itself.
The document's definitions section defines a charging station as an assembly of chargers, electrical cabinets, a metering system and auxiliary low-voltage infrastructure, installed at a rest stop or a satellite charging point and connected to the Scharge app platform. The scope of low-voltage infrastructure is stated clearly: electrical cabinets, cables, connection works and a transformer substation where needed.
In other words, buying the charger is only one part of the job. We go through the remaining parts.
Layer 1: power supply and transformer substation
A 160 kW DC fast charger running at full power draws a very large amount of electricity. If each household uses about 3 kW at peak time, one such charger equals more than fifty households switching on at the same moment. At a site with several chargers, the area's existing low-voltage line usually cannot carry the load.
So the first task in a survey is to check the power capacity available at the site and the distance to the medium-voltage grid. Any site that falls short must plan for its own transformer substation. This is the most time-consuming item, because it involves grid-connection procedures with the power sector. In the Scharge Project, SPT Group supports the procedures for the electricity operation licence and for electricity purchase and sale. We handle the site's local legal matters.
For rest areas on roads, regulation QCVN 43:2024/BGTVT has placed the transformer substation and backup power among the mandatory items, together with the requirement that at least 10% of parking spaces have charging, with a deadline of 01/01/2027. We wrote about this context in our survey notes from the Ho Chi Minh City – Đà Lạt expressway.
Layer 2: electrical cabinets, cables and connection
From the transformer substation or the low-voltage connection point, electricity passes through the distribution cabinet and then along underground cables to each charger. The electrical cabinet houses the switching and protection devices: overcurrent, leakage, lightning protection. The Scharge charger has its own layers of protection inside, but protection at the cabinet is the first barrier for the whole station.
Cables are chosen according to load current and route length. The farther a charger sits from the cabinet, the larger the cable and the greater the losses. That is why site layout and electrical layout must be done at the same time. In the division of roles in the Scharge Project, we are in charge of design and of the works on the land, while the energy technical requirements come from DTH Holdings and Coro Energy. The two sets of drawings must match before the first metre of cable trench is dug.
Layer 3: a separate meter and a management boundary
The Strategic Cooperation Agreement for the Scharge Project records a principle we consider important for every site owner: the energy infrastructure at a site is designed according to the site's tier, with a management boundary, a connection point and a separate meter.
Put simply: the charging station's electricity is measured separately from that of the eatery, guesthouse or workshop next door. Who used how much and who pays how much is clear from the meter. Inside the charger, the metering for each charging session reaches accuracy class 1. These two levels of metering are the basis for transparent reconciliation between the parties and for a correct invoice for the driver.
Layer 4: solar power and storage
At sites with a suitable roof and layout, a solar power system and a battery energy storage system (BESS) are added. In the Scharge Project, this part belongs to Coro Energy, the existing joint-venture partner of DTH Holdings, which takes part in investment according to the scope of each project.
Storage has a role few people notice: peak shaving. When many vehicles charge at once, the storage battery discharges to help, so the power that must be drawn from the grid is lower. Under the agreement, the solar and storage systems are connected to the energy management and operations platform developed by DTH Holdings for metering, monitoring and reporting. This platform connects to the Scharge Platform according to the data standard issued by SPT Group.
Where XECO comes in: stating the scope clearly
We want to state the scope clearly, because this is where things are easily overread.
Under the Memorandum of Understanding, XECO supplies and invests in charger equipment together with low-voltage infrastructure: equipment, installation, warranty and technical maintenance. XECO does not operate the app and does not manage charging sessions or payment. Those parts belong to the Scharge Platform of SPT Group.
XECO is one of the charging-equipment suppliers being considered to participate according to the needs of each project. The selection of suppliers, the scope of supply and the volume of work are considered separately for each project by DTH Holdings together with SPT Group and the parties, based on technical requirements, investment efficiency and commercial terms. The Memorandum states no figure for capital, equipment prices or sharing ratios.
A separate plan for each site cluster
The document records the principle: each site cluster has its own plan, drawn up on the basis of a field survey. We do exactly that. Before discussing the number of chargers, the survey team looks at five things:
- The power capacity available and the distance to the medium-voltage grid.
- The position of the electrical cabinet, the cable route and the connection point.
- Whether the roof and the site can take solar power and storage.
- Vehicle entry and exit, waiting bays and fire safety distances.
- The traffic volume and the types of vehicle travelling the route.
The full seven factors for choosing a location are in the article what a good charging site looks like.
Frequently asked questions about installing Scharge chargers
My site only has a household power supply; can chargers be placed there?
Regular AC chargers of 7–14 kW may suit a small power supply. DC fast chargers almost always need a sufficiently large three-phase supply, and in many cases a dedicated transformer substation. The survey will give the exact answer.
Who invests in the power infrastructure?
It depends on the form of cooperation for each site cluster. The 09/09 documents set out the forms under consideration, while the specific structure is in the detailed agreements signed later. The three forms for site owners are in the article three ways into charging infrastructure.
Is installing solar power mandatory?
No. Solar power and storage are planned for sites with a suitable roof, layout and load profile.
How long does it take from the survey to a running charger?
It depends mainly on the power supply. A site with capacity already available is quick. A site that needs a transformer substation follows the timeline of the grid-connection procedures. We do not give a general figure because it would be wrong for most cases.
Why we tell the story of what is underground
Drivers do not need to know where the electrical cabinet is. They need only one thing: plug in and get power as strong as the charger states, even when other vehicles are charging alongside, even at ten o'clock on a rainy night. That does not come from the charger. It comes from a transformer substation that is large enough, a cable with enough cross-section, a meter that measures correctly and a storage unit that discharges at the right moment.
Only when the part below ground is done properly can the part above ground keep its promise to people on the road.
Site owners who would like a survey are invited to send information to hi@cdrestop.com or call 0981 107 900. The course of the ceremony is in the 09/09 news report.
See the charging station deployment process on the Scharge partnership page.