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Technical notes
Notes on sizing, testing and maintaining batteries and UPS, written by our engineers.
- 01
What is a BESS?
A plain-English primer on battery energy storage systems.
A plain-English primer on battery energy storage systems.
- 02
Battery testing explained
Load-bank vs. impedance testing, and when each one matters.
Load-bank vs. impedance testing, and when each one matters.
- 03
Sizing a UPS
The four numbers you need before anyone quotes you a UPS.
The four numbers you need before anyone quotes you a UPS.
- 04
What is a battery?
A long read on why batteries are everywhere, how they age, and how to specify one properly.
A long read on why batteries are everywhere, how they age, and how to specify one properly.
- 05
What is a UPS?
Online, line interactive, and offline topologies compared.
Online, line interactive, and offline topologies compared.
- 06
What is a rectifier?
DC power systems for telecom and substations, explained.
DC power systems for telecom and substations, explained.
- 07
What is an inverter?
Grid tied, hybrid, off grid, and bidirectional, compared.
Grid tied, hybrid, off grid, and bidirectional, compared.
- 08
What is a power conversion system?
The bidirectional converter that makes a battery useful.
The bidirectional converter that makes a battery useful.
- 09
VRLA vs lithium
Life, cycles, footprint, and cost per usable kilowatt hour.
Life, cycles, footprint, and cost per usable kilowatt hour.
- 10
AGM vs GEL
Two sealed lead acid types that are not interchangeable.
Two sealed lead acid types that are not interchangeable.
- 11
Battery lifespan and replacement
What shortens life, and how to plan replacement in advance.
What shortens life, and how to plan replacement in advance.
- 12
Battery room safety
Ventilation, temperature, clearances, and lithium measures.
Ventilation, temperature, clearances, and lithium measures.
- 13
How to size a BESS
From interval data to installed kWh, with a worked example.
From interval data to installed kWh, with a worked example.
- 14
UPS, BESS, or generator?
Transfer time, duration, cost, and how they combine.
Transfer time, duration, cost, and how they combine.
- 15
How often to test batteries
Intervals for impedance, capacity, and thermal checks.
Intervals for impedance, capacity, and thermal checks.
- 16
What is a portable power station
Capacity, run time, safety, and how it differs from a UPS.
Capacity, run time, safety, and how it differs from a UPS.
- 17
Battery chemistries compared
One table: life, cycles, usable depth, temperature and best duty.
One table: life, cycles, usable depth, temperature and best duty.
- 18
UPS topologies compared
Offline, line interactive, online and modular, side by side.
Offline, line interactive, online and modular, side by side.
- 19
BESS use cases compared
Peak shaving, backup, self consumption, grid services, EV support.
Peak shaving, backup, self consumption, grid services, EV support.
- 20
Battery disposal and recycling
Collection, transport, records and what an auditor will ask for.
Collection, transport, records and what an auditor will ask for.
- 21
Reading a battery test report
What the numbers prove, what downtime it takes, when to replace.
What the numbers prove, what downtime it takes, when to replace.
- 22
Sizing a substation battery
IEEE 485 step by step, with a worked 110 V example.
IEEE 485 step by step, with a worked 110 V example.