2026-09-01

48V 100Ah Telecom Battery: Specifications, Sizing and Selection

Battery ESS48V Telecom BatterySizing Guide

A 48V 100Ah telecom battery is the most commonly specified backup block in the industry — and the most commonly mis-sized. This guide covers what the specification actually means, how to size a bank to your site, and what to settle before placing an order.

What "48V 100Ah" actually means

The name describes two things. 48V is the system voltage the battery is built to work in — a LiFePO4 pack for this duty is 16 cells in series, giving a nominal 51.2V, which sits inside the operating range of a nominal 48V telecom DC system. 100Ah is the charge the pack can deliver.

Multiply them and you get the energy: 51.2V x 100Ah = 5.12 kWh per module. That single number is what determines backup hours, so it is the one to compare between quotations — not the amp-hour figure alone.

Specifications worth reading

Key specifications for a 48V 100Ah LiFePO4 telecom battery
Parameter	Typical value	Why it matters
Nominal voltage	51.2V (16S LiFePO4)	Must sit inside your rectifier's 48V system window
Rated capacity	100 Ah	With voltage, sets the stored energy
Stored energy	5.12 kWh per module	The number that converts directly to runtime
Cycle life	6,000+ cycles at 80% DoD	Drives the replacement interval, not the warranty wording
Communication	RS485 / CAN, SNMP optional	Determines whether the battery can report into your NMS
Certification	IEC 62619, UN38.3, CE	Check the certificate covers the exact model supplied

Sizing to your site

Work backwards from the outage you need to survive. Take the site's DC load in watts, multiply by the required backup hours, and that is the energy you need to deliver — then divide by what one module can actually give you.

A worked example: a site drawing 500 W that must ride out 8 hours needs 4,000 Wh of deliverable energy. One 5.12 kWh module at 80% depth of discharge delivers about 4.1 kWh, so a single module covers it — with a little margin. The same site specified for 12 hours needs 6 kWh, which means two modules in parallel.

The detail that catches people out is deliverable energy rather than nameplate energy. Derate for depth of discharge, for ageing (a pack at end of life holds less than when new) and for temperature. Our runtime guide walks through the calculation properly.

Expanding beyond one module

Modules are connected in parallel to increase capacity — two 100Ah modules give 200Ah at the same voltage, three give 300Ah, and so on. Before specifying, confirm three things with your supplier: the maximum number of modules that can be paralleled, whether the BMS handles balancing across the parallel bank, and how the bank reports state of charge as a single figure rather than as separate modules.

The BMS interface is a specification, not an accessory

If the battery cannot talk to your monitoring system, every health check becomes a site visit. Decide early whether you need RS485 or CAN for a local controller, or SNMP for the battery to appear directly in your NMS over IP. Retrofitting this decision later is far more painful than specifying it up front.

Before you order: a short checklist

Site DC load in watts, and the backup hours actually required
Whether the existing rectifier or UPS stays, and its charge profile
Communication protocol your monitoring system expects
Ambient temperature range at the site, including worst case
Certifications required in your market, and whether they cover the exact model
Space and weight limits in the cabinet or shelter

Our 48V LiFePO4 telecom battery series spans 50-200Ah with smart BMS on RS485 and CAN, and SNMP where the battery needs to report into an operator's network management system. For a real deployment of 48V 100Ah packs with SNMP reporting, see the Pakistan three-site case study.

FAQ

Is a 48V battery the same as a 51.2V battery?

For telecom purposes, yes. Sixteen LiFePO4 cells at 3.2V nominal give 51.2V, which operates inside a nominal 48V system. Suppliers quote both figures for the same pack; 48V is the system voltage, 51.2V is the pack's nominal voltage.

How many hours will a 48V 100Ah battery give me?

Divide the usable energy by your load. Usable energy is 5.12 kWh x depth of discharge x derating for age and temperature — at 80% DoD that is roughly 4.1 kWh, which is about 8 hours at 500 W. See the runtime calculation guide for the full method.

Can I put several 48V 100Ah modules in parallel?

Yes, capacity adds while voltage stays the same. Confirm the maximum parallel count with your supplier, and check that the BMS balances across the whole bank and reports one state of charge for the bank rather than per module.

Do I need SNMP, or is RS485 enough?

RS485 is fine where a local controller or data logger sits next to the battery. Choose SNMP when the battery needs to be polled and send traps to a network management system over IP, alongside the rest of the site equipment.