Blue Sea Systems 3003 500A Battery Selector Switch with AFD
- Brand:
- Blue Sea Systems
- Part no:
- 3003
Image: Fisheries Supply
Where to buy
Specifications
- Continuous rating
- 500 A
- Alternator field disconnect
- Yes
- Ignition protection
- SAE J1171
The Blue Sea Systems 3003 is a four-position battery selector switch rated at 500 amps continuous, with 700A intermittent for 5 minutes and 1600A cranking for 30 seconds when used with 4/0 cable. It also has an alternator field disconnect. The case is rated IP66 and the switch is ignition protected to SAE J1171. Tin-plated copper studs take multiple cables up to 4/0, and the case mounts on a surface or a rear panel. It fits Perko and Guest low amperage hole patterns.
Our take
The 3003's alternator field disconnect protects the alternator diodes if the selector is turned to OFF with the engine running. Its 500A continuous rating holds only with 4/0 cable, so size your cabling to match.
From our buying guide
Perko says its selector switches can be switched between 1, ALL and 2 with the engine running, and that they let you put batteries in parallel for emergency starting. Battle Born advises against that connection with its LiFePO4 batteries.
Check before you buy:
- Its continuous and 5-minute ratings suit your system. Perko rates its medium-duty 8501 at 250 A continuous.
- It has an alternator field disconnect if you need one. Perko says its AFD models protect non-unitized alternators if the switch is turned OFF with the engine running.
- If it's going in a gasoline engine space, the maker lists it as ignition protected.