Why Identical 120 kW Chargers Quote at Different Prices

Two suppliers answer the same specification for a 120 kW site. One total sits well below the other, and both quote sheets list the same headline power, the same connector count, the same protocol. The gap is not a pricing mistake and it is rarely a discount. It is a difference in what was built into the unit, and in what was left for the buyer to pay later. Finding it means reading the quote as a set of decisions rather than as a number.

Two kinds of difference, and only one of them appears on the invoice

The first difference is capital: the hardware, the enclosure, the cable assembly, the metering, whatever is included in the delivered price. It is visible, it is negotiated, and it is the number everyone compares. The second difference is running cost: conversion efficiency, standby draw, software and connectivity fees after the first year, transaction charges, cable and module replacement. It is largely invisible at the point of purchase and it accumulates for as long as the site operates.

A lower capital figure is only a better deal if the running difference over the service life stays below it. That comparison is straightforward once both sides are expressed in the same unit — annual running delta multiplied by expected service years, set against the capital delta. What makes it difficult in practice is that the running side is rarely quoted at all, which is why the cheaper unit so often turns out to be the more expensive one at year three rather than at year one.

Where the difference usually sits

Across the quotes that land on a procurement desk, the variance concentrates in the same places. None of them is hidden deliberately in most cases; they are simply items a supplier chooses to describe in a sentence rather than in a line item.

Where the money moves	How it appears on a quote	How to verify it
Power modules	Not itemised; described as "modular"	Ask for module count, rating and part number
Cable assembly	Length and cooling method omitted	Ask for length, cooling type and mating-cycle figure
Enclosure and protection	IP and IK quoted, corrosion treatment not	Ask for coating specification and condensation control
Metering	"Energy meter included"	Ask for accuracy class and certificate reference
Payment and software	First year bundled, renewal terms absent	Ask for the year-two schedule in writing
Approvals	Logo on the brochure, holder unnamed	Ask for the certificate holder and report number
Service and spares	Warranty period stated, exclusions not	Ask which parts are excluded and what a spare kit costs

The same power figure can be built three different ways

A 120 kW rating says nothing about how that power is produced inside the cabinet. It can come from a small number of large modules or a larger number of smaller ones, and the two are not equivalent in service. Fewer, larger modules usually mean lower cost per kilowatt and a simpler bill of materials. More, smaller modules usually mean finer granularity when one fails, because a single fault removes a smaller share of the total output.

The same logic applies to how the rating is shared between connectors. A unit that divides its output evenly between two connectors behaves differently from one that gives priority to the first vehicle and throttles the second, and both are sold under the same headline number. For a site where vehicles stay for an hour or more, the difference in throughput is often larger than the difference in purchase price. This is the point at which a specification conversation turns into a site design conversation, which is why output per connector and sharing behaviour belong alongside the 120 kW and 180 kW DC charging station selection rather than after it.

There is a third variable that rarely appears in either quote: whether the modules can be replaced on site. A unit built around field-swappable modules carries a different cost structure in year four than one that has to travel back to a service centre, and the difference does not show up until the first failure. Asking for the spare-part price at the quotation stage is the only reliable way to price that risk before it becomes an invoice.

The lines that are often missing from the total

A delivered price and an installed price are different things, and the gap between them is where budgets tend to break. The usual omissions are consistent: freight and insurance, unloading and lifting, civil works and foundations, commissioning, and operator training. Whether each of these sits with the supplier or with the buyer depends entirely on the trade term, and a total quoted on one term compared against a total quoted on another is not a comparison at all.

There is also a category of cost that appears in neither the equipment price nor the installation price: what the site needs in order to accept the load. Transformer capacity, cable runs, protection devices and metering arrangements are site-side items, and on constrained sites they can weigh more than the equipment itself. A supplier quoting equipment only is answering the question that was asked, not the question the project actually faces.

Converting the gap into a figure you can defend

The useful comparison is not total against total, but cost per unit of energy delivered. Take the annual running difference between two options — efficiency loss at the site's actual load profile, standby consumption, software and connectivity fees, transaction charges, expected cable and module replacement — and divide it by the energy the site expects to deliver in a year. The result is an addition to every kWh sold, and it can be compared directly against the capital difference spread over the same period.

Two things follow from this. A site with low throughput will find that running costs matter less than capital, because there is little energy over which to spread them. A site with high throughput finds the opposite: the running difference compounds on every session, and a small per-kWh penalty becomes the dominant number. The same pair of quotes can therefore be correctly decided in opposite directions at two different sites, which is why a price comparison without a utilisation assumption is not a decision.

When the lower quote is the right answer

It is worth saying plainly that the cheaper unit is sometimes the correct choice. Where throughput is low, where the equipment sits on a site with a short remaining lease, where the requirement is a modest AC installation rather than a DC fast charging station, or where a second phase of capacity is already funded and expected, paying for long-life hardware can be paying for capacity the site may not need. In those cases the relevant question is not whether the unit will last a decade, but whether it will do the job for the period the site actually needs it.

The distinction that matters is between a lower specification chosen deliberately and a lower specification discovered later. The first is a design decision with a known trade-off. The second is a cost that was moved off the quote sheet and into the operating budget without anyone agreeing to it. Only the second one is a problem, and it is the one the verification questions in the table above are designed to expose.

A comparison routine that holds up in review

Five steps are enough to make the comparison defensible, and each one produces a document rather than an opinion.

For sites where uptime is measured contractually, the same routine extends to service terms and availability commitments, which is why the commercial comparison is usually reviewed together with the public fast charging solution design rather than in isolation. Where the project spans several sites, the equipment comparison is best run once as a template and then applied identically, so that the differences reported are differences between suppliers and not between the questions asked. Specification sheets and dimension drawings for the equipment types discussed here are usually available through the technical document library.

What the gap actually tells you

A price difference between two compliant-looking offers is information, not a verdict. It says that something in the two offers is not the same, and the only question worth asking is which item that is and who pays for it over the life of the site. Once the difference is traced to a named component or a named clause, it stops being a negotiation about price and becomes a decision about specification — which is a decision the buyer can actually make, and defend afterwards.