Perko Medium Duty Battery Selector Switch, 6-32V, 250A Continuous, Alternator Field Disconnect, Key Lock
Got questions? Ask an expert!
Know someone who needs this?
Share it with your crew or mechanic.
Overview
The Perko 8504DP is a medium duty battery selector switch with a key lock and alternator field disconnect for 6 to 32 VDC marine electrical systems. It is rated for 250 amps continuous load and 360 amps intermittent load, so it fits the kind of battery management setup found on many small to mid-size boats with separate start and house batteries.
This switch gives you OFF, 1, ALL, and 2 battery selection in one surface-mount body. That layout lets you isolate one bank, combine both banks for emergency starting, or route charging and onboard loads the way your system is wired. The ignition-protected housing also makes it suitable for gasoline engine room installations when the rest of the system is wired correctly.
Key features
- 4-position selector with OFF, 1, ALL, and 2 battery settings
- Make-before-break action between 1, ALL, and 2, so switching between those positions can be done with the engine running
- Rated for 6 to 32 VDC systems used with alternators and generators
- 250 amp continuous rating and 360 amp intermittent rating for battery selection and emergency parallel use
- Ignition-protected construction for installations in gasoline engine spaces
- Alternator field disconnect circuit for systems that use non-unitized alternators
- Key lock secures the switch in the OFF position
- Polycarbonate body with brass terminals, 5/16 inch terminal studs, 5-1/4 inch diameter, and 2-5/8 inch depth
Installation and setup
This switch is built for surface mounting and works best where the cable run can stay short and service access at the rear is still practical. The 5-1/4 inch body diameter and 2-5/8 inch depth are worth checking before replacing an older switch in a tight battery compartment, console, or machinery space.
The terminals use 5/16 inch studs, which suits common marine battery cable lugs. On boats that use larger battery cables, rear clearance matters as much as the panel cutout area because the cable bend radius can take up more room than the switch body itself.
Compatibility and fit
This model makes sense on boats that carry two batteries and need clear battery selection at the helm, in a battery locker, or near the engine space. It fits common layouts where one battery is reserved for engine starting and the second bank supports house loads, and it also works in twin-engine systems that use selector switches to manage battery choice at each engine.
The alternator field disconnect feature is relevant on systems with non-unitized alternators. In that setup, the field circuit is routed through the F1 and F2 terminals to reduce the chance of alternator damage if the switch is turned to OFF with the engine running. On unitized alternators with a built-in regulator, that field disconnect circuit is not used.
Shipping
We ship worldwide from the United States. Rates are calculated at checkout based on destination and package weight. Some items include free shipping, which will show automatically. Not every product is eligible for international shipping; checkout will confirm eligibility. We do not ship to PO Boxes except through USPS, and not all packages qualify.
Processing and dispatch
Most orders are verified, packed, and handed to the carrier within 1 to 2 business days. Some products may need extra handling time or ship directly from the manufacturer. For certain international orders, inventory transfers between warehouses may add time. If any delay is expected, we will let you know the dispatch date.
Delivery and tracking
Deliveries are handled by trusted carriers such as USPS, UPS, FedEx, and DHL. Estimated arrival times appear at checkout and depend on your location and the service you choose. These are estimates and can be affected by customs or carrier disruptions. A shipping confirmation with a tracking link is emailed when your order ships, and tracking may take up to 24 hours to update. You can also view tracking in your account.
Duties, taxes, and support
International customers are responsible for any customs duties, taxes, and fees charged by the destination country. If these charges are refused and a shipment returns to us, the carrier’s return cost and any re-entry customs fees will be deducted from the refund. If your order is late or you need help, contact cs@qualityboatparts.com and we will assist you.
Quality Boat Parts is a reseller. Many items include a manufacturer’s warranty, and all warranty service is handled directly by the manufacturer. We do not manage or administer warranty claims on behalf of customers.
Warranty terms, coverage, and duration are set by each manufacturer. Issues involving defects, repairs, or replacements must be addressed with the manufacturer’s support team. When available, the warranty period is listed on the product page. If it is not shown, contact us or the manufacturer for details before purchasing.
To start a claim, the customer must contact the manufacturer and follow their process. Keep your proof of purchase and original packaging, and register the product if the manufacturer requires it, as these are often needed for warranty service.
We are happy to help you find the right contact or documentation, but we cannot decide outcomes or intervene in claim resolutions. For guidance, email cs@qualityboatparts.com.