Log in
Article search:

Electrical audit calculator

This is an interactive version of the spreadsheet devised by Nick Cooke to track your boat's electricity usage. You'll find it useful to read his notes.

In the future we hope to give you the ability to save and load your calculations, but for the meantime, please remember to print out the completed calculator if you might want to refer to it again.

Appliances

230V appliances

AppliancekWh per yearAh per day
Fridge
Freezer

12V lights

Number
PowerW
Current
Hours per day
Ah per day

12V appliances

ApplianceCurrent (A)Hours per dayAh per day

230V equipment

AppliancePower (W)Hours per dayAh per day

Totals

Daily consumption
Charge for storage
Total to be generated each day

Generators

Alternator

Charging rateA
Running to charge batteries (summer)
Running to charge batteries (winter)
Running to replace consumption (summer)
Running to replace consumption (winter)

Solar panels

Nominal total powerW
Power delivered (summer average)
Power delivered (winter average)

Batteries

Batteries installed
Storage required
Batteries required

Results

The boat can be left with the fridge and freezer on for:

In summer:
In winter:

Advanced

Inverter efficiency%
Battery efficiency%
Minimum battery charge%
Battery capacityAh
Days with no engine
Summer solar panel efficiency%
Winter solar panel efficiency%
Summer daylight hours
Winter daylight hours