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.
Trace
Appliances
230V appliances
| Appliance | kWh per year | Ah per day |
|---|---|---|
| Fridge | ||
| Freezer | ||
12V lights
| Number | |
|---|---|
| Power | W |
| Current | |
| Hours per day | |
| Ah per day |
12V appliances
| Appliance | Current (A) | Hours per day | Ah per day |
|---|---|---|---|
230V equipment
| Appliance | Power (W) | Hours per day | Ah per day |
|---|---|---|---|
Totals
| Daily consumption | |
| Charge for storage | |
| Total to be generated each day |
Generators
Alternator
| Charging rate | A |
| Running to charge batteries (summer) | |
| Running to charge batteries (winter) | |
| Running to replace consumption (summer) | |
| Running to replace consumption (winter) |
Solar panels
| Nominal total power | W |
| 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 capacity | Ah |
| Days with no engine | |
| Summer solar panel efficiency | % |
| Winter solar panel efficiency | % |
| Summer daylight hours | |
| Winter daylight hours |