Engineering methodology and editorial policy
Every figure on this site traces to a standard, a manufacturer document or cell-count arithmetic. This page states how the audit is performed, how the guides are written and kept current, and where the limits of what VOLT48 claims lie.
What the compatibility audit determines
The audit documents twelve points of a −48 V DC plant from data the customer captures on site: photographs of the module label and of the whole shelf, the controller menu readings and the site count. Each point is recorded against a reference value and the sheet is signed. It states which lithium architecture — 15S or 16S — fits the plant as documented, with the voltage arithmetic shown, and which controller parameters must change before a battery is energised.
Where the reference values come from
Three sources only. The service window of −40.5 V to −57.0 V is the normal service range of ETSI EN 300 132-2. Module output ranges, factory defaults and controller parameter names are the manufacturer's published values for the specific model. Cell voltages are arithmetic: cells in series multiplied by the per-cell voltage the battery datasheet declares. Where a value is not published, the sheet records it as read on site rather than estimated.
What the audit does not do
It does not certify a product, does not replace the battery datasheet or the controller manual, and does not approve a design. It establishes, in writing, what is installed and what has to change. Commissioning is a separate, priced step that follows the sheet parameter by parameter.
The twelve points, and how each is read
| Point | How it is determined | Reference |
|---|---|---|
| 01 Rectifier module part number | The number printed on the module, not the brand on the cabinet. | e.g. 241115.105 · APR48 · R48-2900U |
| 02 Controller model and firmware version | A condition of entry, not a detail. Below the minimum version, the settings you need are simply not available. | Read it in the controller display menu |
| 03 Output voltage range of the module | The adjustable minimum and maximum the module can actually deliver. | 43.5–57.6 V on a Flatpack2 48/2000 HE |
| 04 Charge profile | Float and equalize at the same value. Lithium is not equalized. | Typically 52–55 V, from the battery datasheet |
| 05 Temperature compensation | Disabled. Sensor selection set to None — not merely unplugged. | Compensation sensor = None |
| 06 Plant thermal runaway management | Off. Thermal protection belongs to the BMS, which measures cells directly. | BTRM off |
| 07 String capacity | Module amp-hours × number of modules, entered in the controller. | 4 × 100 Ah → 400 |
| 08 Charge current limit | Enabled and set. A plant sized for VRLA will otherwise push more current than the pack wants. | 0.1C to 0.5C depending on the battery |
| 09 Low-voltage disconnect | At least 0.5 V above the battery's own disconnect, so the BMS is not what opens first. | ≥ battery LVD + 0.5 V · practical floor 38 V |
| 10 Rectifier walk-in and default voltage | Soft start enabled, so a plant returning after a long outage does not slam full current into a cold bank. | Walk-in enabled · module default voltage set |
| 11 Communications and alarm mapping | Protocol, cabling and BMS version. Without this there is no state of charge or state of health in the controller, and monitoring cannot be sold. | RS485/Modbus · CAN on the rectifier bus |
| 12 Mechanical fit | Rack height in U, frame depth, terminal type and torque, cable cross-section, breaker. | Confirmed per site, from the shelf photo |
| Point | Recorded during the audit |
|---|---|
| 01 Rectifier module part number | Read from the module label |
| 02 Controller model and firmware version | Read from the controller display menu |
| 03 Output voltage range of the module | From the module datasheet |
| 04 Charge profile | Float = equalize, per battery datasheet |
| 05 Temperature compensation | Sensor selection = None |
| 06 Plant thermal runaway management | Off — protection belongs to the BMS |
| 07 String capacity | Modules × Ah, entered in the controller |
| 08 Charge current limit | Set per battery, 0.1–0.5C |
| 09 Low-voltage disconnect | ≥ battery disconnect + 0.5 V |
| 10 Rectifier walk-in and default voltage | Soft start enabled |
| 11 Communications and alarm mapping | Protocol, cabling, BMS version |
| 12 Mechanical fit | From the shelf photo |
How the technical guides are written
Guides answer one question each, with the direct answer first. Every guide carries its publication date and its last update; the update date changes only when the text changes. Guides end with the limits of what they cover and the sources they rely on. Standards and regulations are cited by title and, where a stable public URL exists, linked; documents without a public URL — datasheets, controller manuals — are cited by title only. No link is invented.
Authorship and review
Content is published under the VOLT48 engineering desk, the company's technical function, and is not attributed to a named individual by decision of the company. A technical review date is shown on a guide only when a review has actually taken place. Reader corrections are checked against the sources above before a guide is changed.
Independence
VOLT48 is an independent supplier. It is not an authorised distributor of, nor affiliated with, Eltek, Vertiv, Emerson, Huawei, Delta, Eaton, Mean Well or ZTE. Manufacturer names and part numbers appear on this site solely to identify the equipment for which VOLT48 sources parts and performs audits. No product carrying VOLT48's name is described as certified, approved or compliant; what VOLT48 verifies per shipment is that the supplied model has a UN 38.3 test summary and IEC 62619 documentation bearing that exact model number.
Corrections
If a figure on this site is wrong, write to the address in the footer with the page and the source that contradicts it. Corrections are applied to the page and reflected in its update date.
Sources
- ETSI EN 300 132-2 — Power supply interface at the input of ICT equipment; Part 2: −48 V DC (normal service range −40.5 V to −57.0 V)
- IEC 62619:2022 — Safety requirements for secondary lithium cells and batteries for use in industrial applications (IEC Webstore)
- UN Manual of Tests and Criteria, sub-section 38.3 — lithium metal and lithium-ion cells and batteries (UNECE) (no public URL — cite by title)
- IATA — Lithium Battery Guidance Document (current DGR edition)