Matching the system to the need.
WHAT TO ESTABLISH FIRST
Which circuits the system will supply.
WHY CIRCUITS RATHER THAN THE WHOLE PREMISES
Backing up everything is unaffordable for most businesses.
WHAT TO CALCULATE
The total watts of those circuits: this sizes the inverter
The units consumed during a typical outage: this sizes the batteries
HOW TO CALCULATE UNITS NEEDED
Watts of the backed-up load, multiplied by hours required, divided by a thousand.
WHAT TO ADD FOR LEAD-ACID
Substantially more capacity, because only part is usable.
WHAT TO ADD FOR LOSSES
An allowance for conversion inefficiency.
WHY
Some energy is lost turning stored power into mains-style output.
WHAT INVERTER RATING TO CHOOSE
Above your simultaneous load, with headroom for starting currents.
WHAT TO CHECK ABOUT THE OUTPUT
Whether it is a pure sine wave.
WHY THAT MATTERS
Modified waveforms damage or misbehave with sensitive equipment, including some computers and medical devices.
WHAT TO SPECIFY
Pure sine wave, for anything with electronics.
WHAT CHARGING CAPACITY TO CHECK
How quickly the system recharges when grid power returns.
WHY
If grid supply is brief, slow charging means the batteries never fill.
WHAT TO MATCH
Charge rate to your actual supply pattern.
WHAT TO PLAN FOR
Adding capacity later.
