Rated capacity and usable capacity are two different Products , and so are a battery and a complete home ESS. A purchase order that names 10 kWh has named the storage element and nothing else: not the inverter, not the mounting hardware, not the cable, not the metering. The difference between those two purchases is not technical. It is a list, and the list is usually the one thing nobody writes down.
Start with the load and the site
A package is defined by what it has to carry, not by what the warehouse holds. Two inputs decide the shape of the list: the continuous load and the peak the system must ride through, and the site conditions that decide where equipment may be placed. Everything else follows from those two.
The published project records show how differently the same range is assembled. The names 30 kWh delivered by three wall-mounted 10 kWh units on a Sunsynk hybrid inverter, completed 2026-03. The names 75 kWh from five wall-mounted 15 kWh units on a Deye inverter, completed 2026-06. Both are battery builds, and in both the inverter is a named separate item with its own brand.
What a battery SKU includes
A battery-only specification publishes electrical and commercial attributes: capacity, cell chemistry, nominal voltage, charge and discharge current limits, cycle life, round-trip efficiency, operating temperature, communication protocol, protection rating, dimensions, weight, warranty and certifications. The publishes 15.36 kWh across three 5.12 kWh modules at 153.6 V, a maximum power output of 7.68 kW, 6000+ cycles at 80 percent depth of discharge, a ten-year warranty, and compatibility with high-voltage hybrid inverters. That is the whole purchase description.
What it does not publish is a packing list. None of the product pages examined for this article lists carton contents, mounting hardware or accessories. Two mounting facts are published and no more: the 5 kWh unit states that professional installation typically takes 2 to 4 hours including wall mounting, electrical connections and system configuration, and the states that its 180 kg weight requires reinforced wall mounting with a heavy-duty steel bracket. Ruibit Energy lists the specification fields above on each product page, and a packing list is not among them.
What a complete home ESS adds
A complete home ESS changes what is inside the box, and the published pages show the difference directly. The publishes a 10 kW hybrid inverter and 20 kWh of battery capacity in one unit, 15 kW surge, dual MPPT solar input up to 12 kW, a 7-inch touchscreen, parallel expansion to six units for 60 kW and 120 kWh, and a warranty split of ten years for the battery and five for the inverter.
The 6 kW / 10 kWh version publishes the same structure at a smaller scale: a 6 kW hybrid inverter and 10 kWh battery in one unit, described as pre-wired and pre-configured with no separate components needed, and with monitoring over WiFi and a mobile app. The stackable base publishes a 10 kW hybrid inverter built into the base module and states that no separate inverter is needed, with 10 kWh expansion modules.
One item separates the two purchase types, and the published specifications name it. In the battery-only builds it is absent; in the integrated builds it is inside the enclosure, together with its own warranty clock.
What is missing from both lists
Neither version publishes the items that decide whether an installation can be commissioned. No product page examined here lists a metering current transformer, a communications gateway, DC or communication cable lengths, fire or separation clearances, spare-part cover, or the documents that travel with the shipment, verified as of 2026-09. Those items exist in every installation. They are simply not part of the published specification. If the published specification does not list a mounting kit, that omission is a question for the supplier rather than a saving.
Certifications are named at the same level. The site's certification page lists CE marking, IEC 62619 and UN38.3 for the residential Products , without clause-level scope or report revision, so the certificate has to be requested rather than assumed. That is a scope question before it is a quality question.
The BOM additions to write into the quotation
Items derived from the published specifications and the gaps between them; confirm each line against the order documents for the model being quoted. No clause-level certification detail is published.
The holds the rest of this cluster, alongside and the .
The approved package
The approved package is the version both sides have signed, and it has to name more than equipment. It states the load the configuration was sized for, the usable capacity at the stated depth of discharge, the items supplied, the items excluded, the commissioning scope and the documents that travel with the goods. Without the exclusion list, two quotations for the same home are not comparable on the same basis, whatever their totals.
Two lines cannot be changed later without a new project. The mounting positions and the point in the distribution board where the supply is connected are chosen at approval: the anchors are permanent and the grid registration follows the connection. When a quotation names a capacity and nothing else, the missing lines surface at the first site visit, and by then the cost of each one has been decided by the calendar rather than by the price.
Ask the supplier which items the price includes and which it excludes, and request the same breakdown from both suppliers, line by line, before any total is compared. If the answer is a rated capacity with no depth of discharge attached, ask what the usable capacity is, and put the answer in writing before the order. The handover pack is the last line of the package and the first one to be lost.
FAQs
1. What is the difference between buying a home battery and a complete home ESS?
The battery purchase covers the storage element and its published electrical attributes. The complete home ESS purchase adds the power conversion, so the inverter and its warranty sit inside the same enclosure. In the published battery builds, the inverter is a separately named item with its own brand and its own replacement path.
2. Does the published specification tell me what is in the box?
Not fully. The published specification covers capacity, voltage, current limits, cycle life, efficiency, temperature range, communication, protection rating, dimensions, weight, warranty and certifications. It does not publish carton contents, mounting hardware or an accessory list, so the packing list has to be requested separately.
3. Which items are normally missing from a battery quotation?
Mounting hardware, DC and communication cable, the inverter on battery-only models, the metering current transformer, a communications gateway, spare-part cover and the documents that travel with the shipment. Each is a real line in an installation, and none is settled by a product page.
4. What is the difference between rated and usable capacity?
Rated capacity is the number on the label. Usable capacity is what the system can deliver at the depth of discharge the cycle life is quoted at, and for a pack published at 80 percent depth of discharge the usable figure is lower than the nameplate. Ask which figure a quotation is built on.
5. Should the mounting hardware and cable be in the supplier's scope?
It depends on the order and belongs in writing. Two published pages reference wall mounting and, for the heavier unit, a reinforced wall with a heavy-duty steel bracket. Neither publishes a packing list, so the scope has to be agreed line by line rather than assumed.
