SKU: 89091535474

Blue Sea 300A Black Mini m-Series 4 Position (OFF/1/2/1+2) Battery Selector Switch

Sale price$64.80 Regular price$72.00
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Ships within 48 hours · Estimated delivery Jul 15 - Jul 20

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Description

Blue Sea 300A Black Mini m-Series 4 Position (OFF/1/2/1+2) Battery Selector SwitchCompact High Current Battery Selection for Dual Bank Systems The Blue Sea m Series Battery Switch offers a professional solution for managing two isolated battery banks in marine, RV, and automotive applications. As a 4 position selector switch, it allows you to draw power from Battery 1, Battery 2, or both simultaneously, while also providing a complete disconnect (OFF) for safety and storage. Engineered for systems requiring high power handling in a

Compact High-Current Battery Selection for Dual Bank Systems

The Blue Sea m-Series Battery Switch offers a professional solution for managing two isolated battery banks in marine, RV, and automotive applications. As a 4-position selector switch, it allows you to draw power from Battery 1, Battery 2, or both simultaneously, while also providing a complete disconnect (OFF) for safety and storage. Engineered for systems requiring high power handling in a small footprint, this switch is ideal for switching battery banks to all loads or combining them for emergency starting.

Whether you are outfitting a small boat with an outboard motor, setting up a dual battery system in a 4WD, or managing power in a camper trailer, the m-Series provides the reliability needed for critical electrical connections. Its compact design solves the problem of limited mounting space without compromising on amperage capacity.

Complete Control Over Two Battery Banks

This selector battery switch simplifies power management by allowing you to choose which battery bank powers your engine or house loads. The "1+2" position combines both banks, effectively paralleling them to provide extra cranking amps during emergency starting situations or to charge both banks simultaneously from a single charging source. This flexibility is essential for ensuring you always have a backup power source available if your primary starting battery is depleted.

Safe Switching with Make-Before-Break Technology

Protecting your vehicle's sensitive electronics and charging components is paramount. This unit features a make-before-break contact design, which allows you to switch between battery banks (e.g., from 1 to 2) while the engine is running without interrupting power flow. This feature prevents potentially damaging voltage spikes that can harm alternators and sensitive navigation or communication equipment, ensuring seamless operation during use.

High-Current Performance and Compatibility

Despite its mini form factor, the m-Series is built to handle significant electrical loads. It is rated for 300A continuous current, making it suitable for most marine and automotive DC circuits up to 32V. For short bursts, such as engine cranking, it can withstand up to 900A for 30 seconds. The switch utilises 3/8"-16 (approx. M10) tinned copper studs that provide maximum conductivity and corrosion resistance. These terminals are capable of accepting heavy-duty ring terminals and cables up to 4/0 AWG (approx. 120mm²), ensuring minimal voltage drop even in high-demand setups.

Flexible Installation Options

Installation in tight spaces is made easier with versatile mounting configurations. The switch can be surface mounted, front panel mounted, or rear panel mounted, accommodating various dashboard and locker layouts. It fits standard mounting holes (accepts #10 screws or approx. M5) and includes a snap-on rear cover to insulate terminals, adding an extra layer of safety against accidental short circuits.

  • 4-Position Selector: OFF, 1, 2, and 1+2 for versatile battery management
  • High Current Rating: 300A continuous, 500A intermittent (5 min), 900A cranking (30 sec)
  • Ignition Protected: Safe for installation aboard petrol-powered boats
  • Make-Before-Break: Safely switch between banks without stopping power flow
  • Heavy-Duty Terminals: 3/8"-16 (approx. M10) studs accept up to 4/0 AWG (approx. 120mm²) cables
  • Water Resistant: IP66 rating ensures durability in damp marine environments

Reliable Power Management for Your Next Adventure

Ensure your electrical system is safe, efficient, and versatile with the Blue Sea m-Series Battery Switch. Whether you need to isolate a starting battery or combine banks for a jump start, this switch delivers professional-grade performance.

Secure your power system today with this industry-leading battery selector switch.

Shipping Notes
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
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SKU: 89091535474

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Product Reviews
A
Amazon Customer
Pawtucket, US
★★★★★ 5
Mag-Safe Magnetic
Great product! The MagSafe compatibility is perfect—it snaps right on instantly. I prefer this over the wireless charging mounts because those always seem to overheat my phone on long trips. This is lightweight, stable, and the all-black aesthetic blends right into the Tesla screen frame. 10/10 for any Tesla owner.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 15, 2026
S
SuperBanker
Dallas, US
★★★★★ 4
Perfect Little Mount for Tesla Drivers
I like that this Tesla phone mount snaps onto the back of the screen cleanly and holds my iPhone with a strong MagSafe grip. It keeps the phone right where I need it without blocking the view, and the adjustable angle makes navigation super easy to see while driving. I do not like that it can wobble a tiny bit on rough roads, and the magnet isn’t as strong if you’re using a thicker case. Overall, a great accessory that makes the Model 3/Y setup even more convenient!
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Reviewed in the United States on November 14, 2025
P
photogirl5
Chelsea, US
★★★★★ 5
Tesla MagSafe mount for phone
Very cool phone mount that I hadn’t thought to purchase until I saw it as an option on Vine. Easy to install using the included adhesive strips pre-attached to the mount. It has a nice firm grip on the MagSafe for the phone and the mount itself sticks very well to the back of the Tesla screen with no issues. It is in the perfect location in the dashboard area as it doesn’t block any view or buttons. No negative aspects to my experience with this product.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 21, 2025
J
J. Youm
Charlottesville, US
★★★★★ 4
Arm can be positioned in many ways, but doesn't grip as hard and the phone rattles in rough roads
I liked how this product looked in the picture so I ordered it. But when I installed it, I found out that it doesn't have the same amount of "grip power" because you have to turn a little knob on the side to tighten the grip and it's not that easy to do compared to other screw type phone mounts that have bigger screws. The magnet was slightly weaker than my existing phone holder but it was adequately strong. It was good to see how one could position the phone in different positions due to the way the arm is designed to be moved and adjusted. But the one biggest thing I didn't like is how the phone kept on shaking/rattling when I drove over rough roads. The metal arm is quite thin and although it's metal and not plastic, due to the thinness of the material, it was easily rattled and made the phone rattle a lot in return. Over smooth roads this won't be a big problem though. I wasn't quite satisfied with this, although it's adequately good enough.
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Reviewed in the United States on October 3, 2025
A
Verified Purchase
Amazon junkie
Battle Creek, US
★★★★★ 5
The search is over…
Style: 15W Charger
I have purchased so many mounts, but this one is perfect. It is easy to remove and apply to the screen. I don’t have to worry about damaging the screen with adhesive. The magnet is strong, and as a result, the phone is very stable. The most important benefit for me is the multiple viewing positions. The vertical placement and height are prefect. This is a quality product.
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Reviewed in the United States on February 17, 2026

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