Audit lithium compatibility
We document the rectifier, controller, firmware and output range of your −48 V plant and deliver a signed twelve-point sheet stating which lithium architecture fits and which parameters must change.
Request an auditLithium compatibility for −48 V DC plants, documented before you buy the battery.
VOLT48 is an independent −48 V DC specialist. We read your rectifier, controller, firmware and output range, then sign a sheet stating which lithium architecture your plant accepts and what has to change.
−40.5 V−57.0 V
−54.0 V 15S at full charge, inside the range
−57.6 V 16S at full charge, 0.6 V outside
Full charge at 3.60 V per cell. Whether your plant accepts either one is what the audit determines.
Plants and equipment we serve
- Eltek
- Vertiv
- Emerson
- Delta
- Huawei
- Eaton
- Mean Well
- ZTE
VOLT48 is an independent supplier. It is not an authorised distributor of, nor affiliated with, the manufacturers named above. All trademarks belong to their respective owners and are used here only to identify the equipment we source parts for.
15S versus 16S
A 51.2 V battery is not a 48 V battery
Telecom equipment on a −48 V bus is specified to a normal service range of −40.5 V to −57.0 V. Cell count decides whether a lithium pack stays inside that window at full charge.
| Parameter | 15S | 16S |
|---|---|---|
| Cells in series | 15 | 16 |
| Nominal voltage (3.20 V per cell) | 48.0 V | 51.2 V |
| Full charge at 3.60 V per cell | 15 × 3.60 V = 54.0 V | 16 × 3.60 V = 57.6 V |
| Upper limit of the service range | −57.0 V | −57.0 V |
| Margin to that limit | 3.0 V inside | 0.6 V above |
| Orientation | Within the window | Above the window |
Indicative result. Actual compatibility also depends on the rectifier, controller, firmware, charge profile, temperature compensation, low-voltage disconnect and BMS.
Three ways in
Extend what is viable. Replace only when the engineering requires it.
Every enquiry lands in one of three places. Each has a defined deliverable, a stated lead time and a written scope.
Find a module or controller
Nine product families and 28 designations, current and legacy — Eltek, Vertiv/Emerson, Huawei, Delta, Eaton, ZTE. Send the number printed on the label; the quotation states condition, lead time and warranty.
Search the catalogueDesign or replace a DC plant
When the audit shows the plant has reached the end of its serviceable life: rectifier systems, shelves, controllers and DC distribution sized to your load and growth, from qualified manufacturers.
Describe the site
The deliverable
What the signed sheet looks like
Twelve points, documented per site and signed. The sample below shows the structure only — every value is read from your equipment during the audit.
VOLT48
Lithium compatibility sheet
Sample — not a site verdict
SiteSample site · one −48 V plant
| 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 |
Architecture that fitsDetermined per site — 15S or 16S, with the arithmetic shown
Signed by the VOLT48 engineering desk
USD 450 per site · free for the first ten accounts
Request the audit How the twelve points are determined
Catalogue
Find your module by brand, model or part number
Nine families, 28 designations. Every card carries the identifier printed on the unit — that number is what we quote against.
Eltek Flatpack2 48V Rectifier Modules
241115.105 · 241119.105
Active
Eltek Flatpack S & Legacy Flatpack Modules
Flatpack S 48/1800
Legacy
Huawei R4850G2 & R4875G1 Rectifier Modules
R4850G2 · R4875G1
Active
Vertiv NetSure & Emerson R48 Rectifier Modules
R48-2900U · R48-3200
Mixed
Delta ESR 48V Rectifier Modules
ESR-48/56 · ESR-48/56AC
Active
Eaton APR48 Rectifier Modules
APR48-3G · APR48-ES
Legacy
ZTE ZXDU & ZXD Rectifier Modules
ZXD2400 · ZXD3000
Mixed
DC Plant Controllers & Monitoring Units
Eltek Smartpack / Smartpack2
Mixed
48V LiFePO4 Telecom Lithium Batteries
48 V LiFePO4 50Ah · 15S
Active
No family matches. Send the number anyway — most legacy 48 V plants are still sourceable.
Technical centre
All guides
Engineering guides, with the arithmetic shown
Direct answers to the questions asked before a lithium purchase or a legacy part search. Dated, sourced and reviewed under a published methodology.
-
Can I put a 51.2 V rack battery in my −48 V telecom plant?
The honest answer is: probably not without validating it first — and the reason is arithmetic, not commercial preference.
Updated -
Is the Eltek Flatpack2 discontinued?
No. And the reason so many people believe otherwise is worth understanding, because the same mistake makes buyers replace plants that did not need replacing.
Updated -
Does my controller need a firmware update before a lithium retrofit?
This is the question that decides whether a site is a two-hour job or a project, and it is almost never asked before the battery is ordered.
Updated -
What float voltage do I set for lithium on a Flatpack2?
The parameter list is short. Getting it wrong is what turns a lithium retrofit into a warranty argument.
Updated -
How do I identify my 48 V DC plant?
Everyone photographs the module. Almost nobody photographs the controller — and the controller is what decides what you are allowed to install next.
Updated -
What paperwork does a telecom lithium battery need to ship?
Two documents and one rule. The documents are routine; the rule is the one that quietly rewrites your warranty process.
Updated
Methodology
From a structured form to a powered site, in four steps
Everything starts from data you can capture with a phone. No site visit is required for the audit.
Remote audit
You complete the audit form — or send a part number and a photo of the label for spares.
Signed sheet
You receive the twelve-point compatibility sheet, signed — or the quotation with condition, committed lead time, price and warranty.
Hardware to order
New or genuine new-old-stock from a qualified manufacturer, with pre-shipment inspection against the datasheet and the warranty stated in writing.
Guided commissioning
Parameter-by-parameter guidance for your technicians or local contractor, with communications validated so the bank can be monitored from day one.
San José, CA to Dubai
From San José, California to Dubai — a career in telecom and data centre DC power
The company
Fifteen years in 48 V DC power, now operating from Dubai
The experience behind VOLT48 began in San José, California, managing 48 V DC rectifier systems for cellular towers and repeaters — Delta/Ericsson, Eltek-Valere and Mean Well equipment across the United States and Latin America. The task was always the same: keep critical infrastructure energised.
VOLT48 applies that experience from Dubai to the GCC, the wider Middle East and Africa, India and Latin America. Our position is straightforward: we extend the assets that remain technically viable, and we recommend replacement only when the engineering requires it.
- 15+ years field experience
- 48 V DC specialist
- Legacy & end-of-life plants
- China & Taiwan sourcing
Contact
Email
sales@volt48.com
Describe the site. You will have a technical answer within one business day.
Replacement module, full DC plant, lithium retrofit or a project quotation — send the details and we respond with scope, lead time and price stated in writing.
Phone / WhatsApp
—Based in
Dubai, UAE — serving GCC, MEA, India & Latin America