--- product_id: 8376872 title: "Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e" brand: "blue sea systems" price: "Β£40.29" currency: GBP in_stock: true reviews_count: 13 category: "Blue Sea Systems" url: https://www.desertcart.co.uk/products/8376872-blue-sea-systems-e-series-battery-switch-single-circuit-on store_origin: GB region: United Kingdom --- # Tactile switch for no-light use 325A heavy-duty current rating Compact & versatile mounting Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e **Brand:** blue sea systems **Price:** Β£40.29 **Availability:** βœ… In Stock ## Summary > πŸ”΄ Switch smart, power strong β€” never miss a beat on the water or road! ## Quick Answers - **What is this?** Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e by blue sea systems - **How much does it cost?** Β£40.29 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/8376872-blue-sea-systems-e-series-battery-switch-single-circuit-on) ## Best For - blue sea systems enthusiasts ## Why This Product - Trusted blue sea systems brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Engine Room Ready:** Ignition protected for safe installation even in gasoline engine compartments. - β€’ **Operate Blindfolded:** Tactile textured knob lets you switch on/off easily in low or no light conditions. - β€’ **Power Through with Confidence:** Handles up to 325 amps for robust marine and RV power management. - β€’ **Fits Anywhere, Installs Everywhere:** Compact design with multiple mounting options for tight or tricky spaces. - β€’ **Secure Connections, Zero Resistance:** One-piece tin-plated copper studs accept multiple cables and ensure minimal power loss. ## Overview The Blue Sea Systems 9003E e-Series Single Circuit Battery Switch is a compact, ignition-protected rotary switch rated for 32V DC and 325A continuous current. Designed for marine and RV applications, it offers versatile mounting options, tactile controls for low-light operation, and robust copper studs that accept multiple cables for secure, low-resistance connections. Ideal for isolating or combining battery banks, it ensures reliable power management in tight spaces and harsh environments. ## Description The Blue Sea Systems 9003E e-Series battery switch provides simple and reliable single circuit power control for marine electrical systems. Designed to turn one battery bank on or off, it helps isolate electrical loads during maintenance or storage. Its compact footprint allows installation in tight spaces, while flexible mounting options support both surface and rear panel configurations. The switch is ignition protected for safe use in gasoline powered boat engine rooms. Tin plated copper terminal studs are designed to accept multiple cable connections and provide secure, low resistance contact. A textured knob and face enable operation in low light conditions. This model does not include an alternator field disconnect. Review: High quality disconnect - Solid item, does as expected. The product seems top quality. Used as a battery disconnect for a camper, I used it in a modular battery box and it's sits super tight using a 3 5/8 hole saw. I used out door sealant to waterproof around the hole. Review: Solved battery trickle problem, strong with nice flush mount - The switch was a breeze to install, feels very solid, and I expect it to last a long time. I'm sure this is a little over-kill for my single marine battery, but I'm willing to pay an extra twenty bucks for peace of mind. This switch has a very high threshold for the load of amps that occur upon starting the engine, and it's size and weight imply that I won't be replacing it any time soon. The ability to flush-mount it worked great and keeps it looking professional. Regarding my specific setup: I have a standard marine battery running to a 120hp Yamaha outboard. For the last couple seasons I have had an issue with the battery dying if I didn't use the boat for several weeks. Physically disconnecting the battery terminals after using the boat solved the problem, but it wasn't the most user-friendly solution for the rest of the family. The issue suggests a larger trickle from the battery than there should be, but it's not worth my time or money to figure out what device is pulling current even when the key is off. So the solution was to get a simple switch that does the same thing as physically disconnecting from the terminals. It's worked great so far; no battery drain after leaving the boat for a month. Originally I intended to mount it below the dashboard, but I ended up taking more simple route and mounted it closer to the battery in one of the compartments under a back seat. I used a 3 5/8" hole saw to cut through the plastic wall of the seat, about halfway up from the floor. Then I pushed the switch into the hole, marked the four locations of the bolts, drilled four small holes, and mounted the switch with four nuts and bolts. NOTE, I needed the following extra materials to install the switch: 1. 3 5/8" hole saw (not needed unless flush-mounting, and you could use a different tool too) 2. Four bolts and nuts (at least 3.5" in length, I forget the diameter) 3. Wire and crimp-connectors to extend the wire from the battery to where I mounted the switch, remember that you only need to extend the positive (+) cable to the switch) ## Features - SINGLE CIRCUIT CONTROL: Turns one battery bank on or off; isolates power during maintenance or storage - COMPACT DESIGN: Small footprint supports installation in tight spaces; flexible placement options - FLEXIBLE MOUNTING: Surface or rear panel mounting supports multiple installation configurations - DURABLE CONNECTIONS: Tin plated copper studs accept multiple cables; support secure high torque connections - LOW LIGHT OPERATION: Textured knob and face allow operation by feel in low visibility conditions ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B000MMC914 | | Actuator Type | Rotary | | Best Sellers Rank | #8,787 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #2 in Boat Battery Switches | | Brand | Blue Sea Systems | | Brand Name | Blue Sea Systems | | Circuit Type | 1-way | | Color | Red | | Compatible Devices | Boats | | Compatible with Vehicle Type | Boat | | Connectivity Protocol | X-10 | | Connector Type | Idc | | Contact Material | Tinned Copper | | Contact Type | Normally Open | | Control Method | Touch | | Control Type | ON/OFF | | Controller Type | Boat | | Current Rating | 350 Amps | | Customer Reviews | 4.8 out of 5 stars 717 Reviews | | Global Trade Identification Number | 00632085900359 | | Included Components | e-Series On Off Battery Switch | | International Protection Rating | IP66 | | Item Dimensions | 2.9 x 6.38 x 8.63 inches | | Item Type Name | BATTERY SWITCH ON/OFF | | Item Weight | 0.59 Kilograms | | Lower Temperature Rating | 1 Degrees Celsius | | Manufacturer | Blue Sea Systems | | Material Type | Plastic | | Model | 9003e | | Mounting Type | Panel Mount, Surface Mount | | Number of Items | 1 | | Number of Positions | 2 | | Operating Voltage | 48 Volts (DC) | | Operation Mode | ON-OFF | | Part Number | 9003e-BSS | | Smart Home Compatibility | Not Smart Home Compatible | | Switch Type | Rotary | | Terminal | Spdt | | UPC | 632085900359 | | Unit Count | 1.0 Count | | Upper Temperature Rating | 1 Degrees Fahrenheit | | Warranty Description | Limited Lifetime Warranty | | Wattage | 16800 watts | ## Product Details - **Brand:** Blue Sea Systems - **Connector Type:** Idc - **Contact Type:** Normally Open - **Current Rating:** 1 Microamps - **Item dimensions L x W x H:** 2.9 x 6.38 x 8.63 inches - **Material:** Metal - **Operating Voltage:** 48 Volts - **Operation Mode:** ON-OFF-ON - **Switch Type:** Temperature Switch - **Terminal:** Spdt ## Images ![Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e - Image 1](https://m.media-amazon.com/images/I/81oD4fs1tCL.jpg) ![Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e - Image 2](https://m.media-amazon.com/images/I/71z8utETJ2L.jpg) ![Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e - Image 3](https://m.media-amazon.com/images/I/51tvx4OvJML.jpg) ![Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e - Image 4](https://m.media-amazon.com/images/I/51zM3e8DqxL.jpg) ![Blue Sea Systems e-Series Battery Switch Single Circuit, On/ Off, 48V DC, 350 A, Red, 9003e - Image 5](https://m.media-amazon.com/images/I/41Br+QfuncL.jpg) ## Available Options This product comes in different **Pattern, Style** options. ## Questions & Answers **Q: I'm considering using this as a battery isolator for a winch on my Jeep. Can it handle the current? and what are the physical dimensions?** A: Your winch maker will list amperage for various amounts of load. Also switches will show three amperages they can tolerate for different amounts of time. So this switch is rated for 350 amps "continuous" (ie on for hours or permanently) 600 amps "intermittent" (for five minutes according to specs), and 1,200 amps "cranking"/peak for 30 seconds. OK so my SmittyBilt 9500 XRC Generation 3 winch has the following draws: 80 amps pulling zero lbs (winding rope in), 160 amps pulling 2,000 lbs, 220 amps pulling 4,000 lbs, 280 amps pulling 6,000, 340 amps pulling 8,000 lbs, and 385 amps pulling maximum of 9,500 lbs. H20 smitty and Second Gen XRC smitty use about 10% more amps. Also you "should" have a safety margin of 20%, ie no more than 80%. Now that means switch is ok continious running my winch are 2/3 of max load, and switch is fine running extreme max of winch load five minutes, five minutes rest, five minutes run, etc. BUT if you are anywhere over 50% of winch capacity/load you are going to run winch five minutes and rest the winch for five minutes anyway. so if your numbers are like mine you are ok. Check your winch makers specs on their website. Look until you find all numbers for the range of loads since the basic single amperage number they will list will be about 60% of max. I would say 90% of up to 12,000 lb winches are ok with this switch. But that presupposes you have at least read up on winching and know that you will damage your winch if you pull at max for more than four or five minutes. goodluck. PS blue sea's web page lists the contentious, intermittent five minutes and peak 20 seconds for all its switches. The other red "m" model is 300 continuous, this "E" is 350 continuous, and the gray one is 600, 900,1750 **Q: where can I get wiring instructions with diagram?** A: You tube has a few I found helpful. **Q: Package says it’s compatible with up to 4/0 awg. my batter bank is 200a lithium tuning through 2/0 awg wire to my bus bar. will this switch work?** A: It is compatible with any wire that fits the terminals. AWG 4, 2, or 0. The important thing is the current and voltage. At 48 volts this switch should be good at 233 amps continuously. Here is my complete review: Fabulous switch. I have mine on my golf car and switch between two 48 volt battery banks; It is specified at Continuous rating: 350A, Maximum voltage: 32V DC. Doing the math: Power = Current x Voltage. Thus, 350 x 32 = 11,200 Watts that this switch can handle. So, 11,200 / 48 = 233 Amps continuous ... at 48 volts this switch should be good at 233 amps continuously. see less **Q: What is alternator field disconnect vs the regular product without AFD? Looking to use on a camp trailer.** A: You do not need afd on a trailer, only on a vehicle with an alternator such as a motorhome or boat. It protects the alternator diodes upon disconnect. ## Customer Reviews ### ⭐⭐⭐⭐⭐ High quality disconnect *by L***R on April 26, 2026* Solid item, does as expected. The product seems top quality. Used as a battery disconnect for a camper, I used it in a modular battery box and it's sits super tight using a 3 5/8 hole saw. I used out door sealant to waterproof around the hole. ### ⭐⭐⭐⭐⭐ Solved battery trickle problem, strong with nice flush mount *by N***Y on May 11, 2014* The switch was a breeze to install, feels very solid, and I expect it to last a long time. I'm sure this is a little over-kill for my single marine battery, but I'm willing to pay an extra twenty bucks for peace of mind. This switch has a very high threshold for the load of amps that occur upon starting the engine, and it's size and weight imply that I won't be replacing it any time soon. The ability to flush-mount it worked great and keeps it looking professional. Regarding my specific setup: I have a standard marine battery running to a 120hp Yamaha outboard. For the last couple seasons I have had an issue with the battery dying if I didn't use the boat for several weeks. Physically disconnecting the battery terminals after using the boat solved the problem, but it wasn't the most user-friendly solution for the rest of the family. The issue suggests a larger trickle from the battery than there should be, but it's not worth my time or money to figure out what device is pulling current even when the key is off. So the solution was to get a simple switch that does the same thing as physically disconnecting from the terminals. It's worked great so far; no battery drain after leaving the boat for a month. Originally I intended to mount it below the dashboard, but I ended up taking more simple route and mounted it closer to the battery in one of the compartments under a back seat. I used a 3 5/8" hole saw to cut through the plastic wall of the seat, about halfway up from the floor. Then I pushed the switch into the hole, marked the four locations of the bolts, drilled four small holes, and mounted the switch with four nuts and bolts. NOTE, I needed the following extra materials to install the switch: 1. 3 5/8" hole saw (not needed unless flush-mounting, and you could use a different tool too) 2. Four bolts and nuts (at least 3.5" in length, I forget the diameter) 3. Wire and crimp-connectors to extend the wire from the battery to where I mounted the switch, remember that you only need to extend the positive (+) cable to the switch) ### ⭐⭐⭐⭐⭐ Blue Sea Systems 9003e Battery Disconnect Switch On/Off Type *by S***N on January 5, 2014* The Blue Sea Systems 9003e battery disconnect switch is very high quality with a solid feel and tough plastic housing. I ordered this switch for my electric golf cart. The voltage rating of the switch exactly matches my 48 volt system and far above the 200 amp maximum of the golf cart. I don't expect to be switching off the power while current is flowing, but good to know that the switch is capable of handling anything that the golf cart can produce. I mounted the switch from the rear with only the round face exposed for a more professional look; The minimum hole size is 3 5/8" to accept the round part of the switch; had to borrow this large size hole saw from a contractor. The studs on the back are 3/8" diameter and easy to access. The only thing that could be better is if it came with a non-metallic cover plate for the back to protect against accidental contact with the studs; This is not an issue for those who are surface mounting the switch. All golf carts should come with a maintenance switch like this. I can now be assured that there are no parasitic current draws on the battery pack when not in use. You just have to remember to turn it back on when charging or when you want to use the cart! ## Frequently Bought Together - Blue Sea Systems 9003E e-Series Battery Switch, On/Off, Red - Blue Sea Systems 5026 ST Blade Fuse Block 12 Circuit with Ground and Cover - 16 Gauge Marine Wire 16 AWG Marine Grade Wire Include 16AWG 120FT Red & 120FT Black,16 Gauge Tinned Copper Electrical Cable for Boat Automotive Speakers Lighting Solar Outdoor RV Camper Trailer --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.uk/products/8376872-blue-sea-systems-e-series-battery-switch-single-circuit-on](https://www.desertcart.co.uk/products/8376872-blue-sea-systems-e-series-battery-switch-single-circuit-on) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-05-31*