ElectricalCapacityDC
Calculating DCDirect current Electrical Capacity
Summary
Calculating DC (direct current) load for the DC primary system is an activity in determining the capacity of the boat'sSecond house bank of DC batteries. Over estimating the numbers to provide comfort in the individual calculations is not recommended. It is better to add spare capacity calculations directly to the house bank specifications.[1][2]
AAmpere (amp), SI unit of electrical current link to a spreadsheet is provided.
DC Load
Download spreadsheet: Microsoft Office xlsx | Libre/Open Office ods
| ITEM | NUMBER | AMPS | AMPS TOTAL | HOURS PER DAY | DUTY CYCLE | AMP HOURS |
|---|---|---|---|---|---|---|
| FIXED LOADS | ||||||
| Cabins | ||||||
| Electronic Equipment | ||||||
| Radio Transmitter | 1 | 0.0 | 0.0 | 2.0 | 8%percent | 0.0 |
| SSB | 1 | 0.0 | 0.0 | 1.0 | 4% | 0.0 |
| Ventilation | ||||||
| Forward Cabin | 10 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Aft Cabin | 2 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Heads | 2 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Galley | 1 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Pilot House | 2 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Salon | 2 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Instruments | ||||||
| Alarm System (stnby) | 0 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Autopilot | 0 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Depth Sounder | 1 | 0.0 | 0.0 | 24.0 | 100% | 0.0 |
| Radar | 1 | 0.0 | 0.0 | 24.0 | 100% | 0.0 |
| GPSGlobal Positioning System | 1 | 0.0 | 0.0 | 24.0 | 100% | 0.0 |
| SubTotal | 0.0 | |||||
| Machinery | ||||||
| Navigation Lights | 1 | 5.0 | 5.0 | 24.0 | 100% | 5.0 |
| Bilge Blowers | 0 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Bilge Pumps | 0 | 0.0 | 0.0 | 1.0 | 4% | 0.0 |
| Wipers | 0 | 0.0 | 0.0 | 24.0 | 100% | 0.0 |
| Searchlight | 0 | 0.0 | 0.0 | 1.0 | 4% | 0.0 |
| Instruments | 0 | 0.0 | 0.0 | 24.0 | 100% | 0.0 |
| Ventilation - Engine | 2 | 0.0 | 0.0 | 24.0 | 100% | 0.0 |
| SubTotal | 5.0 | |||||
| Other | 0 | 0.0 | 0.0 | 0.0 | 0% | |
| SubTotal | 0.0 | |||||
| Total Fixed | 5.0 | |||||
| INTERMITTENT LOADS | ||||||
| Cabins | ||||||
| Cabin Lighting | ||||||
| Halogen 10 WWatt | 5 | 0.8 | 4.0 | 6.0 | 25% | 1.0 |
| Halogen 20 W | 32 | 1.6 | 51.2 | 6.0 | 25% | 12.8 |
| Halogen 35 W | 0 | 2.9 | 0.0 | 6.0 | 25% | 0.0 |
| 3 LEDLight emitting diode Reading Light | 0 | 0.03 | 0.0 | 3.0 | 13% | 0.0 |
| 6 LED Reading Light | 0 | 0.06 | 0.0 | 3.0 | 13% | 0.0 |
| 9 LED Reading Light | 10 | 0.09 | 0.9 | 3.0 | 13% | 0.1 |
| 10 W Fluorescent | 0 | 0.80 | 0.0 | 6.0 | 25% | 0.0 |
| 13 W Fluorescent | 0 | 0.80 | 0.0 | 6.0 | 25% | 0.0 |
| 15 W Fluorescent | 0 | 1.20 | 0.0 | 6.0 | 25% | 0.0 |
| 18 W Fluorescent | 0 | 1.50 | 0.0 | 6.0 | 25% | 0.0 |
| 20 W Fluorescent | 0 | 1.60 | 0.0 | 6.0 | 25% | 0.0 |
| 26 W Fluorescent | 0 | 2.10 | 0.0 | 6.0 | 25% | 0.0 |
| SubTotal Lights | 13.9 | |||||
| Cigarette Lighter | 0 | 0.0 | 0.0 | 1.0 | 4% | 0.0 |
| Electronic Equipment | ||||||
| SW Receiver | 1 | 0.0 | 0.0 | 1.0 | 4% | 0.0 |
| Stereo - Saloon | 1 | 8.3 | 8.3 | 12.0 | 50% | 4.2 |
| Stereo - Dinette | 1 | 8.3 | 8.3 | 12.0 | 50% | 4.2 |
| Stereo - Main Cabin | 1 | 8.3 | 8.3 | 4.0 | 17% | 1.4 |
| Microwave | 0 | 68.0 | 0.0 | 0.0 | 0% | 0.0 |
| SubTotal Equipment | 9.7 | |||||
| Machinery | ||||||
| Trim Tabs | 0 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Horn | 1 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Anchor Windlass | 0 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Winches | 0 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Fresh water Pumps | 1 | 0.0 | 0.0 | 2.0 | 8% | 0.0 |
| Air Conditioner | 1 | 0.0 | 0.0 | 0.0 | 0% | 0.0 |
| Furnace - Diesel | 1 | 7.5 | 7.5 | 7.0 | 29% | 2.2 |
| Refrigeration | ||||||
| Cold Plate | 1 | 35.0 | 35.0 | 2.0 | 8% | 2.9 |
| Constant Cycling | 0 | 7.0 | 0.0 | 8.0 | 33% | 0.0 |
| Sewage Pump | 1 | 0.0 | 0.0 | 2.0 | 8% | 0.0 |
| SubTotal Machinery | 5.1 | |||||
See also ElectricalCapacityAC.